the ecology, behavior, and conservation of a west …

ORNITOLOGIA NEOTROPICAL 17: 105–146, 2006© The Neotropical Ornithological Society

THE ECOLOGY, BEHAVIOR, AND CONSERVATION OF A WEST INDIAN CORVID, THE WHITE-NECKED CROW (CORVUS

LEUCOGNAPHALUS)

James W. Wiley

U. S. Geological Survey, Reston, Virginia, USA. Email: [email protected]

Resumen. – Ecología y conservación del Cao (Corvus leucognaphalus). – El Cao anteriormente habi-taba en St. Croix, Puerto Rico y Hispaniola. Ahora sobrevive sólo en Hispaniola, donde las poblacionesdeclinan por algunas de las mismas razones responsables de su extirpación en Puerto Rico: fragmentacióny pérdida del hábitat, y tiroteo. La depredación de los huevos y pichones por el Zorzal Pardo (Margarops fus-catus) también fue una razón importante en la extirpación del Cao en Puerto Rico. Estudié el Cao en laRepública Dominicana intermitentemente entre 1974 y 2004. La especie ocupa una gama amplia de hábi-tat, incluyendo costas húmedas y bosque montano, bosque de pino, bosque de cactus, manglar pantanosoy sabana de palmeras. Su conducta vocal es compleja y diversa, al igual que la de otros cuervos. El Cao sealimenta de una amplia variedad de plantas y presas animales. Durante los periodos de alimentación, losCaos seleccionaron plantas en 76,4% de las observaciones, mientras que del total de presas ofrecidas a lospichones 51,6% fueron animales. Las áreas centrales de actividad de tres parejas reproductoras promedia-ron 9,8 + 3,7 ha, considerando que el tamaño de su territorio promedio era de 5,5 + 5,2 ha. La construc-ción de los nidos comenzó a finales de Enero. Los nidos fueron estructuras voluminosas construidas enlo alto de los árboles. El período de incubación fue de aproximadamente 18–22 días y el período de anida-ción de 35–44 días. El tamaño de la nidada fue de cuatro huevos en seis nidos y tres huevos en un nido queinspeccioné hasta el término de la anidación. De 27 huevos en esos siete nidos, 25 pichones eclosionaron y22 volaron de los mismos. La atención al nido fue más alta durante la incubación, y fue disminuyendodurante el período de anidación de los pichones. No se observó ningún tipo de depredación y sólo hubouna incidencia de ectoparasitismo en pichones. Se recomienda un programa de reintroducción del Cao aPuerto Rico como viable e importante para la supervivencia de la especie.Abstract. – The White-necked Crow (Corvus leucognaphalus) formerly inhabited St. Croix, Puerto Rico, andHispaniola. It survives only in Hispaniola, where populations are declining for some of the same reasonsprimarily responsible for its extirpation from Puerto Rico: habitat fragmentation and loss, and shooting.Egg and chick depredation by the Pearly-eyed Thrasher (Margarops fuscatus) was also important in the extir-pation of the Puerto Rico population. I studied the crow in the Dominican Republic intermittently from1974 to 2004. The species occupies a wide range of habitats, including wet coastal and montane forest,pine forest, cactus forest, mangrove swamp, and palm savanna. Its vocal behavior is complex and diverse,more like that of ravens than of crows. White-necked Crows fed on a wide variety of plant and animal mat-ter. Foraging crows selected plant materials in 76.4% of my observations, whereas animals made up 51.6%of the food items delivered to nestlings. Core activity areas of three breeding pairs averaged 9.8 + 3.7 ha,whereas their average territory size was 5.5 + 5.2 ha. Nest building began in late January. Nests were bulkystructures placed high in trees. Eggs were incubated 18–22 days and the nestling period was 35–44 days.______________

1Mailing address: Maryland Cooperative Fish and Wildlife Research Unit, 1120 Trigg Hall, University ofMaryland Eastern Shore, Princess Anne, Maryland 21853, USA. E-mail: [email protected]

105

WILEY

Clutch size was four eggs at six nests and three eggs at one nest I inspected at clutch completion. Twenty-five chicks hatched from 27 eggs at those nests, and a total of 22 fledged. Adult nest attendance was high-est during incubation, then declined through the nestling period. I observed no predation and only a mod-erate incidence of ectoparasitism of chicks. A program of reintroducing the White-necked Crow to PuertoRico is recommended as feasible and important to the survival of the species. Accepted 8 December 2005.

Key words: Behavior, breeding, conservation, corvid, Corvus leucognaphalus, Dominican Republic, ecology,extinction, extirpation, Haiti, Hispaniola, Puerto Rico, vocalization, White-necked Crow.

INTRODUCTION

The four species of West Indian corvids, allin the genus Corvus, with their raucouscalls and flocking behavior, are prominentmembers of avian communities in theAntilles. Resident and visiting naturalistshave accumulated considerable anecdotalinformation through incidental observationsof these birds, yet the basic natural historyof West Indian corvids is poorly known(Johnston 1961, Cruz 1972, Goodwin1976). With the rampant habitat alterationoccurring throughout most of the WestIndies, several corvid populations havedeclined or disappeared (Barbour 1943,Greenway 1958, Bond 1973, Goodwin 1976).The White-necked Crow (Corvus leuco-gnaphalus; Fig. 1) formerly occurred inHispaniola, Puerto Rico, and St. Croix(Fig. 2), but today survives only in Hispaniola,including Île de la Gonäve and IslaSaona. Because of its decreasing range andextirpation from entire landmasses, a mainobjective of my study was to determinewhy the crow disappeared from partsof its former range. Resolution of thequestion of the crow’s decline required abasic knowledge of its life history and behav-ioral ecology. Thus, my objectives includeddetermining the crow’s general ecology andbehavior. Finally, my objectives includedproviding managers with information toallow them to make biologically sound deci-sions for the conservation of the White-necked Crow.

STUDY AREAS

I conducted fieldwork in the DominicanRepublic in October 1974, December 1975 toJuly 1976, July and August 1978, July to Sep-tember 1982, August 1989, March to April1996, May to June 2000, June and December2001, January, March to May, and August2002, and December 2004. I watched crowsin several locations, but my major study areawas in Los Haitises, north-central DominicanRepublic, and Pedernales, southwesternDominican Republic (Fig. 3). The Haitisesregion is rugged limestone karst (“mogotes”)of Miocene origin, with narrow valleys havingdeep soils, and extensive natural hardwoodforests (Zanoni et al. 1990). Elevations at LosHaitises ranged from 250 to 360 m. The areais west of the village of Pilancón, and approx-imately 20 km northeast of Bayaguana(i.e., study area centered at 18°55’76”N,069°36’11”W). The nearest weather stationsto the Haitises study area, Bayaguana andSabana de la Mar (35 km northeast), reportedmean annual rainfalls of 181 cm and 212 cm,and mean annual temperatures of 24.5°C and25.2°C, respectively. The rainfall and tempera-tures in my Los Haitises study area probablyfall between those given for the two stations.Maximum rainfall occurs from May to Octo-ber. The karst is quite permeable, and stand-ing water is rare.

The plant community in Los Haitises isclassified as a subtropical wet forest (Hold-ridge Classification; OAS Ecological Map,Washington, DC, 1967). Characteristic trees

106

WHITE-NECKED CROW ECOLOGY AND CONSERVATION

include cupey (Clusia rosea), fourleaf buchena-via (Buchenavia capitata), West Indian mahog-any (Swietenia mahagoni), kapoktree ( (Ceiba

pentandra), masa (Tetragastris balsamifera), Amer-ican muskwood (Guarea guidonia), Spanishcedar (Cedrela odorata), bullwood (Sloanea

FIG. 1. Adult White-necked Crow at nest with late-stage chicks, Los Haitises, Dominican Republic.

FIG. 2. Recent and present distribution of the genus Corvus in the West Indies (After Olson & Hilgartner1982). † = extirpated or extinct population.

107

WILEY

berteriana), and corcho bobo (Pisonia albida);plant names follow Little & Wadsworth1964), Little et al. (1974), Zanoni et al. 1990,and USDA, NRCS (2004). The study areaconsisted of virgin forest, as well as active andabandoned small farms. Although the regionwas declared a national park (Parque NacionalLos Haitises) in 1976, clear-cutting and burn-ing for farming accelerated through 2004.Subsistence crops are mixtures of severalfruits and vegetables. Abandoned farms arequickly invaded by higuillo de hoja menuda(Piper aduncum), matchwood (Didymopanaxmorototoni), monkey’s hand (Lepianthes peltata),and sword fern (Nephrolepsis multiflora). Fur-ther descriptive information on the study areais presented by Wiley & Wiley (1981), Snyderet al. (1987), and Zanoni et al. (1990).

The Pedernales study area included thecoastal plain and low foothills east of thetown of Pedernales. The area is eroded lime-stone within the subtropical thorn woodland

life zone. The plant community of the area ishighly disturbed and represents a secondaryreplacement of more diverse past communi-ties. Porknut (Acacia macracantha) comprisesabout 50% of the cover, with Hispaniolanroyal palm (Roystonea hispaniolana), coconutpalm (Cocos nucifera), and mango (Mangiferaindica) also abundant. Other important treesand shrubs included Capparis ferruginea, Jamai-can caper (C. cynophallophora), tuna (Opuntiamoniliformis), lignum-vitae (Guajacum officinale),baitoa (Phyllostylon brasiliense), Gouane palm(Coccothrinax ekmanii), and chechen (Metopiumbrownei) (Fisher-Meerow 1983, Fisher-Meerow& Judd 1989). Annual rainfall at Pedernalesaverages 47.1 cm, with two main rainfall peri-ods, May and June, and September and Octo-ber. Annual temperature averages 27.9°C.

I examined crow nests in the wetdegraded forest in the coastal foothills southof Barahona (mean annual temperature26.7°C; mean annual rainfall 101.9 cm; wet-

FIG. 3. Hispaniola (Haiti and Dominican Republic), showing study areas and other sites mentioned intext.

108


test months May and June, and Septemberand October). The area has calcareous soilsand is within the subtropical humid forestzone, with characteristic tree species includingWest Indian mahogany, Haitian catalpa(Catalpa longissima), caracolí (Pithecellobium glau-cum), and Hispaniolan royal palm.

METHODS

I collected behavioral and ecological data bywatching crows from lookouts in tops ofemergent trees, from hilltops that offeredoverviews of crow ranges, and from blindsplaced in trees 3–12 m from five nests. Toavoid disturbing nesting crows and ensurenormal behavior at nests, I entered blindsbefore first light. If an entire day was notspent in the blind, I exited the area whencrows were known to be distant. I gathereddata on the interactions of crows and otheravian species opportunistically from lookoutsand blinds. Distances of crow and other spe-cies’ activities were estimated at 10–m incre-ments from 0–150 m, and at 25 m incrementsbeyond 150 m. Activities of crows and otherspecies were plotted on field maps of thestudy sites. Some distances were measured(e.g., particularly between nests and sites oftenvisited by crows), but most were estimated. Icharacterized crow core activity areas as thatportion of the total activity area where 80% (n= 3 pairs, 1649 activity points) of activities(foraging, loafing, pair interactions, localmovement, roosting) were observed. Sexdetermination was possible from behavior atthe three nests where most intensive observa-tions were made. Although no crows weremarked, I could often identify individualsthrough unique behavior and plumage charac-teristics.

To examine White-necked Crow popula-tion changes over a protracted period, I sur-veyed bird populations along trails throughrepresentative habitats in the Haitises (4

routes) study areas from 1974 to 2004. Threesurvey routes were 1-km long, whereas oneroute (LH # 3) was 1.4-km in length. I sam-pled bird populations in March and April,with surveys conducted during the first twohours of daylight on two consecutive days foreach route per month. I surveyed each 100 mtransect section within a 6-min samplingperiod, recording all observations per section.Surveys were suspended during rain or whenwind speed reached Beaufort 4. If rainsquallswere short, a disrupted survey was continuedwhen the squall passed and leaf drip subsided.I recorded all birds seen or heard, with noattempt to record detection distances to indi-viduals or to species under varying samplingconditions. Thus, the counts provide roughindices of abundance, but cannot be used toprovide absolute area-density figures.

To examine nest-building behavior androle of mates in nest construction, I watchedthree crow pairs from lookouts placed inemergent trees and from blinds situated intrees adjacent to nests at Los Haitises. Obser-vations were made in full-day bouts frombefore first light through last light. Determi-nation of gender of individuals was some-times possible based on courtship andcopulation behavior. More often, however, Iwas not able to determine sex of pair mem-bers and characterized the individuals as “A”and “B” during interactions. Quantification ofbuilding behavior (e.g., material delivery rates,source distance from nest) was based onbouts when the subjects were visible for theentire behavioral sequence.

Crow vocalizations were recorded on aUher 4000 IC Report tape recorder with aparabolic reflector microphone and analyzedusing Raven (ver. 1.0) sound analysis software.

I collected descriptive data on crow eggsand nestlings, using vernier calipers andspring scales to measure eggs and chicks. Fewmeasurements were taken of chicks because Iavoided disturbing nesting pairs to ensure

109

WILEY

their normal behavior during my observa-tions. The day of hatching could not be deter-mined for all chicks I examined; in thosecases, I estimated the chicks’ ages based onknown ages of nestmates and behavioralobservations made from blinds. I divided thenesting period into four stages for analyses ofbreeding behavior: incubation, and early (firstthird of nestling period), mid- (middle third),and late-nestling stages.

I evaluated diet choices of White-neckedCrows by observing food items delivered tonests, as well as observing foraging and trans-fers of food between mates. Biomass esti-mates, particularly for plant matter, are crudebecause the amount of material delivered tonests could not always be accurately deter-mined; e.g., especially regurgitated fruit pulpand smaller seeds. Because crows typicallycarried small food items to the nest in theirsublingual pouch, identification of foods wasinfrequent and then possible only whenpassed between adults or to the chicks, orwhen dropped to the ground or on the nestrim. Although not always clearly visible, cer-tain plant foods (e.g., Clusia rosea pulp) couldbe determined from the distinctive color orconsistency. I was also able to make identifi-cations by inspecting cached items or remainsat and below nests. Weights of food items aremostly best estimates, based on approximateamounts delivered. Many plant parts wereweighed, but the mass of others was esti-mated from weights taken of comparablysized, similar items. I weighed representativesof most animal species delivered to nests bycrows.

Interviews of older woodsmen were con-ducted in Puerto Rico from 1973 to 1986.Individuals were asked about their recollec-tions of crows, their past numbers and distri-bution, and natural history as part of abroader effort to determine past wildlife andhabitat characteristics in Puerto Rico.

Statistical analyses follow procedures in

Zar (1975). Standard deviations are used asthe measure of variance about the mean. Sig-nificance level was set at 0.05.

I present my results in the context of areview of reported observations pertinent tomy observations of White-necked Crows.

RELATIONSHIPS AND DESCRIPTION

The White-necked Crow is the largest ofthe four corvids in the West Indies, includingthe Cuban Crow (Corvus nasicus) of Cuba, Islade Juventud (formerly Isle of Pines), and thesouthern-most Bahama Islands, the endemicJamaican Crow (C. jamaicensis), and the PalmCrow (C. palmarum) of Hispaniola, with scat-tered, relict populations in Cuba (Fig. 2).Based on differences in voices, plumages andtarsus and bill sizes, Garrido et al. (1997) splitC. palmarum into two species: C. minutus,restricted to Cuba, where it is rare and local,and C. palmarum, endemic to Hispaniola,where it is common. Wetmore (1920, 1937)reported that Corvus pumilis, an extinct speciesintermediate in size between leucognaphalus andpalmarum, formerly inhabited Puerto Rico andthe Virgin Islands. Olson & Hillgarner (1982),however, suggested that C. pumilis could beadded under C. nasicus, although it might be alarger representative of C. palma-rum. If C.nasicus formerly occurred in Puerto Rico andthe Virgin Islands, it was presumably sympat-ric with C. leucognaphalus, thereby dispellingany consideration that C. nasicus and C.leucognaphalus are conspecific (see below).Brodkorb (1959) proposed a new species, C.wetmorei, based on fossils from New Provi-dence, but Olson & Hilgartner (1982) consid-ered C. wetmorei as a junior synonym of C.nasicus.

The White-necked Crow is a large corvid(about 50 cm in length), completely black,with a blue-purplish gloss, especially on theupper parts. Long, soft semiplume-like feath-ers cover the throat. Rictal bristles cover the

110


nostrils and are directed forward and up, as inravens (Fig. 1). Gundlach (1874) noted theseforward-directed bristles and remarked on

the similarity between Corvus nasicus and C.leucognaphalus in the structure of the nasal bris-tles. The adults have bright orange-red irides,

FIG. 4. Anxiety display of White-necked Crow, Miches, Dominican Republic, 1976. A: Perched crow,showing white bases of neck feathers. B & C: Calling with high-caw’s, and throat feathers splayed. D & E:Head down, tail splayed and flipped, and wings out from body. F & G: Leaving perch in direction ofintruder, giving high-caw’s.

111

WILEY

which Württemberg (1835) characterized asfire-red eyes. The crow’s common name isderived from the snowy-white bases of theneck feathers, visible only during displays(Fig. 4). Although C. leucognaphalus shares thisplumage characteristic with the ChihuahuanRaven (C. cryptoleucus) of southwestern NorthAmerica and Mexico, Jollie (1978) consideredthis similarity as meaningless parallelism.Baumel (1953) reported a White-neckedCrow with vestigial claws on the wings, thefirst such report for the family Corvidae.

The White-necked Crow shows moderatesexual dimorphism in size but none in plum-age. This is similar to several corvid species(e.g., Carrion Crow Corvus corone corone andHooded Crow C. c. corniz; Saino & De Ber-nardi 1994). The average sexual size dimor-phism index (D.I.; Storer 1966) of White-necked Crow specimens measured byJohnston (1961) is 7.80 + 2.37 for four mea-surements (Wing = 7.19, Tail = 4.72, Tarsus= 9.89, Culmen = 9.41). Males are signifi-cantly larger than females in each of thesemeasurements (Wing: P = 0.001, df = 20;Tail: P = 0.01, df = 17; Tarsus: P << 0.001, df= 11; Culmen: P < 0.001, df = 24; Fisher-Behrens t-test). Cuban Crows (meanD.I. = 2.47+ 0.78), Palm Crows (meanD.I. = 2.45 + 2.19),and Jamaican Crows (meanD.I. = 2.41 + 1.51)show less sexual size dimorphism than theWhite-necked Crow.

There has been substantial debate overthe relationship and taxonomy of the White-necked Crow. Johnston (1961) placed leuco-gnaphalus in a group that included the Ameri-can Crow (Corvus brachyrhynchos) and CubanCrow, and apart from a second group thatincluded the other West Indian crows. In con-trast, Goodwin (1976) and Jollie (1978) placedleucognaphalus with jamaicensis and nasicus, sepa-rate from brachyrhynchos and palmarum. Basedon results using DNA hybridization to deter-mine relationships among taxa, Monroe &Sibley (1993) similarly arranged leucognaphalus

next to nasicus, jamaicensis, and palmarum.Indeed, much earlier, leucognaphalus, jamaicensis,and nasicus were placed together in a separategenus, Microcorax (Sharpe 1877). Dorst (1947)and Brodkorb (1959) considered C. nasicus tobe a subspecies of C. leucognaphalus. Based onvocalizations, Bond (1977) suggested a rela-tionship among C. nasicus, C. leucognaphalus,and C. jamaicensis, all of which he believed tobe most closely related to C. cryptoleucus of themainland. Bond (1977) further suggested thatC. palmarum was derived from C. ossifragus(Fish Crow) and represents a later invasion ofthe Greater Antilles.

RANGE AND STATUS

The White-necked Crow formerly occurredin Hispaniola, Puerto Rico, and St. Croix. InSt. Croix, the crow is known solely fromaboriginal kitchen middens (Wetmore 1918,1925). The crow’s decline and disappearancefrom Puerto Rico is well documented. It wascommon during the earliest years of explora-tion of the island (Abbad & Lasierra 1788). Inthe last quarter of the nineteenth century,Gundlach (1874, 1878) reported the White-necked Crow could still be found in goodnumbers in interior and eastern Puerto Rico(i.e., Lares, Pajita, Utuado, Caguana), and wastold that the crow was still common in theeastern region of the island where he did notvisit. When Wetmore (1916, 1927) visitedPuerto Rico in 1911–1912, however, the crowwas almost extirpated. Wetmore encounteredthe crow in the Sierra de Luquillo, where itwas still fairly common, and learned of otherindividuals below San Sebastian, northwest-ern Puerto Rico. Wetmore (1916) observedthat the White-necked Crow could not adaptto changed conditions and he expected itwould only survive in the government forestreserve (now the Caribbean National Forest)in the Sierra de Luquillo. The last PuertoRican population of the crow did persist in

112


the Sierra de Luquillo but, unfortunately, Wet-more’s prediction for its survival there did notcome true.

My interviews with older woodsmen whohad a long familiarity with the Sierra deLuquillo area yielded a unanimous opinionthat the crow became quite rare or disap-peared from the Sierra in the 1930s or 1940s.Manolo Vázquez (age 65 years in 1976) sawabout 40 crows at Icacos Valley in 1950. Bythe late 1950s, few crows remained there(Mason 1960). Moises Parilla recalled thecrow occurred near his home in Sonadora inthe 1940s, but reported it as gone by the late1950s. The crow was last sighted in the Sierrade Luquillo in 1963 by H. A. Raffaele (Bond1973, Raffaele 1983) and Cayo Burgos (pers.com.), an area resident and former woods-man. Despite numerous, spurious reports ofWhite-necked Crows in Puerto Rico, allproved to be escaped American Crows,imported as pets (Raffaele 1983, pers. com.;pers. observ.).

The White-necked Crow formerly occur-red in large numbers throughout much ofHispaniola (see Wetmore & Swales 1931 forreview). Württemberg (1835) described flocksof hundreds of whitenecks in the early 19thcentury. Beck (1916) observed several hun-dred crows in the swamp near the mouth ofrío Bararrote on 23 November 1916. By 1927,the White-necked Crow was still consideredcommon in some areas, but was becomingrare in many regions (Wetmore & Swales1931). Dod (1978, 1992) described it asdeclining and extirpated from the larger partof its former range in the Dominican Repub-lic. She described the crow as very common inmany localities as late as 1950, but since thattime it numbers were reduced because ofhunting. Most recently, Keith et al. (2003)described the White-necked Crow as a locallycommon to uncommon resident island-wide,but by 1982 it had become rare in pine foresthabitat and at high elevations, so that now it is

only locally distributed in lowlands.Little has been reported of the crow’s

present status and distribution in Haiti.Although Wetmore & Swales (1931) encoun-tered it to 2650 m in Massif de la Selle in April1927, it has more recently been reported asuncommon above 1500 m (A. O. U. 1998).Bond (1928) found it “very common in thenorthern pine belt” of Haiti. Woods & Otten-walder (1983, 1992) recorded it from the Cita-delle region, but absent from the Morne laViste and Pic Formon–Pic Macaya regions inthe high mountains. Golding (1983) recentlyreported the White-necked Crow in north-western Haiti. Dod (1992) reported that inHaiti it “is very common around Port-au-Prince, where there are trees, and at an agri-cultural station at Damian…since the Haitiansare not allowed to have guns.” The crow wasreported as “casual” on Île de la Gonäve(A. O. U. 1998).

In the Dominican Republic, I found theWhite-necked Crow restricted mainly to largetracts of habitat, and there it was local in dis-tribution. Dod’s (1978) distribution map isdeceptive in showing the crow occurringthroughout the Dominican Republic, whereasits distribution is actually quite uneven. Areaswhere I observed substantial crow popula-tions included Los Haitises, Miches, theSamaná Peninsula, and the Sierra de Baho-ruco. Also, it was seasonally abundant on IslaSaona during the aggregated breeding ofWhite-crowned Pigeons (Patagioenas leucoceph-ala) . Nowhere did crow numbers approachthose described by early visitors.

HABITAT

Sallé (1857) and Wetmore (1916) suggestedthat the White-necked Crow requires largeexpanses of natural forest and soon disap-pears where its habitat is degraded. WhenWetmore visited Puerto Rico in 1911–1912,he found the White-necked Crow primarily in

113

WILEY

rugged forested terrain of the inland moun-tains. This may indicate a preference for thishabitat, but may also reflect the near-com-plete destruction of the island’s lowland habi-tat by the time of Wetmore’s visit.

In Hispaniola, records exist for the crow’soccurrence in several habitat types, includingpine forests (Danforth 1929, Bond 1947, Dod1978), broadleaf forests, cactus forests (Peters1917), mangrove swamps (Beck 1916, Peters1917, Abbott in Wetmore & Swales 1931,Wetmore & Swales 1931), and palm savannas(Dod 1978). I found it most often in wet for-ests, particularly the extensive tracts in LosHaitises, but also the remnant coastal rain for-est (Sabana de la Mar, Peninsula de Samaná)and degraded rain forests in the mountainsabove Miches. A small breeding population

has persisted in the dry coastal woodland insouthwestern Dominican Republic (Peder-nales). Whitenecks were also regular visitorsto the dry woodlands and agricultural areassurrounding Lago Enriquillo (particularly thewestern and northwestern shores), movingbetween the lowlands and nearby foothillsand mountains to the north. The crow wasseasonally abundant (during pigeon breedingseason) in the dry coastal forest of southeast-ern Dominican Republic and Isla Saona, butotherwise was not common there. I did notfind it to be common in the dry foothill andscrub habitats, nor in the pine forests. There,the Palm Crow was locally common, asreported by Danforth (1929), Wetmore &Swales (1931), Bond (1947), and Dod (1992).The two species are sympatric in some areas,

A

B

FIG. 5. A: Caw vocalization of White-necked Crow, Los Haitises, Dominican Republic, 1976. B: High caw,Los Haitises, Dominican Republic, 2001.

114


but the Palm Crow is the more abundant indrier sites. The White-necked Crow is appar-ently less tolerant of human activity than thePalm Crow, as I saw few White-necked Crowsaround human habitations. The exception tothat pattern was the breeding population atPedernales, where pairs nested in palmsclose to houses and active agriculturalfields. The Palm Crow often nested, roosted,and fed in palm groves about small towns(e.g., Duvergé).

VOCAL BEHAVIOR

Corvids are typically highly vocal, with a com-plex repertoire of calls; e.g., Chamberlain &Cornwell (1971) catalogued 23 distinct vocal-izations of the American Crow, each with aunique environmental and behavioral context,whereas Connor (1985) noted 18 call types inthe Common Raven (C. corax). The complexand diverse vocal behavior of the White-necked Crow is more like that of ravens thanof crows (Cherrie 1897, Danforth 1929, Wet-more & Swales 1931, Bond 1947). Madge &

Burn (1994) described its vocalizations as “Anextraordinary mixed babbling, bubbling andsquawking, very varied in content, some notesrich and sweet, others raucous andsquawked.” Gundlach (1874) noted that thevoice of the White-necked Crow was like thatof C. nasicus. Württemberg (1835) and Cherrie(1897) reported the whiteneck forming noisyflocks. Cherrie (1897) remarked that “Theirnoise can be heard a long way off when anumber are collected together. The note initself is very peculiar, and appears to be com-pounded of a half musical cackle and a whis-tling kind of laugh, but sometimes it is harshand discordant. It is one of the most strangenoises I have ever heard from any bird.” HereI describe some of the more common vocal-izations and their contexts. Chick vocalbehavior is described in the Nestlings section.

Caw. This was the most common White-necked Crow vocalization I heard (Fig. 5a).The caw was typically used in advertisementon the territory, including when the adultcrows entered or left the nest site. It was also

FIG. 6. Bubbling call of White-necked Crow, Los Haitises, Dominican Republic, 1976.

115

WILEY

used when residents chased territorial invad-ers (especially Red-tailed Hawks Buteo jamai-censis, Ridgway’s Hawks Buteo ridgwayi, TurkeyVultures Cathartes aura) or when a humanapproached the nest. On occasion I heard aretreating crow (territorial invader) give caw’sas it was pursued by territory holders. Whenan adult called with caw’s after discovering meat its nest, or in response to a territorialinvader entering the nest territory, its matequickly approached to join in the defense.

Meinertzhagen (1926) noted that Corvusbrachyrhynchos minutus “...and C. b. palmarum [=C. palmarum] are the only West Indian crowswhich ‘caw’; all others, ‘leucognaphalus, nasicus,and jamaicensis,’ babbling and chattering.”

High-caw. This vocalization was similar to theadvertisement caw, but was higher in tone,more intense, and was used in contexts ofgreater excited than more guttural caw(Fig. 5b).

Bubbling call. This is a complex call withseveral variations, but having a general pho-netic pattern of “Gollygop” (Fig. 6). It wasused in several contexts, including duets bymated pairs in flight, in greetings by pairmembers, intraspecific supplantations (byaggressors and chased birds), and whenother species (e.g., Cattle Egret Bubulcus ibis)

were chased. Bubbling calls were occasionallygiven by the chased crow in interspecificinteractions. When a foraging pair of adultcrows discovered me in a treetop lookout,they flew over my head giving bubbling vocal-izations, then landed in a nerby tree, wherethey continued to direct these calls at me asthey displayed the white base of their neckfeathers.

Week-woo call. A complex “week-woo-oo” or“week-wick-woo-oo”(Fig. 7) was given by the ter-ritory holder as it returned from evicting aterritory invader Rowley (1974) described a“Victory” call given in similar context for theAustralian Raven (Corvus coronoides).

Guk calls. These are a complex series of callswith several variations, but with the generalform of “guk - guk - guk - gu-woo” (Fig. 8), andsometimes with the bubbling “gollygop” as thefinal element. The gollygop element was some-times used alone by the chased crow in inter-specific interactions. Guk calls were used inhigh intensity intra- and inter-specific interac-tions, usually by the chaser, but occasionallyby the chased birds, too.

Weeak call. A loud, gutteral “weeak-weeak-weeah” was intermittently given by birds asthey gathered twigs for nest building.

FIG. 7. Week-woo call of White-necked Crow, Los Haitises, Dominican Republic, 1976.

116


Wag call. A gargling “wag” was given by birdsflying to their nests with building materials.

Gauch call. Adult White-necked Crows occa-sionally gave a loud, rauchous “gauch-gauch-gauch” as they left the nest after deliveringmaterials.

Hic-gu-gik-gu call. A high-intensity hic-gu-gik-gucall was given during intraspecific interactions,typically by members of territorial pairsdirected toward territory invaders, but also bysupplanted invaders.

High-low gargles. Gargles are complex vocaliza-tions consisting of alternating high-pitchedcalls and low guttural sounds, typically givenby several birds during apparent high-anxietysituations, particularly in congregations ofmany birds.

“Nah” Older chicks gave begging calls,sounding like a soft version of the caw: “nah.”

VISUAL DISPLAYS

Assertion. Low- and moderate-intensity asser-tion consisted of the crow orienting towardanother bird and calling, usually with caw’s. In

more intense assertion bouts, the crow’s bodywas held horizontal, with its neck out-stretched and neck feathers splayed. At thesetimes the white bases of the neck featherswere clearly visible.

Anxiety and excitement. In some territorialdefense bouts, one or both resident pairmembers landed next to an intruding crow.Usually the residents, but sometimes also theintruder, lowered their heads and forcefullyhammered on their perches with their bills.Leaves and vines were also plucked andshredded with the bill. Such displays of possi-ble tension were common among crows thatgathered in groups. Displays involving lower-ing the head, or “Herabstarren,” have beenreported as displacement behavior for otherspecies of Corvus, as has hammering (Poncy1938, Skead 1952, Coombs 1960, Gwinner1964, Wittenberg 1968).

Tail flipping is apparently associated withanxiety and was the most consistent displayduring assertion bouts. The tail flips were oflow amplitude and were rapidly executed. Thecrow held its head down at the plane of theback or slightly below it when the angle of theback was about 10° below horizontal. Crowsdisplaying high anxiety lowered their head far-ther and the tail was held more upright

FIG. 8. “Guk” vocalization of White-necked Crow, Los Haitises, Dominican Republic, 1976.

117

WILEY

(Fig. 4). White-necked Crows tail flipped (5–6flips) when they landed after a flight, whenthey arrived at the nest with twigs or food,when one crow “greeted” another (usually itsmate), and when a bird perched after an aerialattack during intra- and interspecific chases(including mobbing humans at the nest). Tailflips were sometimes given during vocalbouts. In high-intensity territorial interactions,crows called with high-caw’s, oriented towardthe intruder with heads down, then quicklymoved to an upright position and gave aquick tail flip. Tail flips were a downwardmovement with retrices quickly splayed so thetail was 1/4-opened. During the display, thecrow’s throat feathers are somewhat erect andthe bird’s wings are held slightly out from thebody and above the head. Palm Crows alsotail flip when aggitated but, although theyhold their body horizontal as do White-necked Crows, the tail is flipped down, ratherthan up as in the White-necked Crow. PalmCrows give individual tail flips after each cawcall element. Holyoak (1983) suggested thesetail movements in Palm Crows function asflight intentions or self-assertive movements.Tail flipping has been reported for severalother corvid species (e.g., Eurasian Rook Cor-vus frugilegus and Carrion Crow; Coombs1960). Madge & Burn (1994) reported thatthe White-necked Crow lacked the tail flickingmovement, but that the behavior is character-istic of the Palm Crow.

Alarm. When potential predators (includinghumans) approached a crow’s nest, the resi-dents exhibited a more intense version of theAssertion Display. The body and tail wereheld horizontal, with the neck outstretchedand the bird’s head held slightly below theplane of the back. The bird partially extendedand raised its wings and splayed its neckfeathers, showing the white bases. The birdgave vigorous tail flips and called with caw’s.Wetmore (1916) reported that White-necked

Crows responded to his presence by landinghigh in a tree, where they “crouched” andcalled, lifting their wings nervously.

Antagonistic display. In this display, the territoryholder leaned forward, lowered its head belowthe plane of its back, held its body horizontal,fanned its tail, hung its wings somewhat, andcalled with bubbling calls and hic-gu-gik-guvocalizations, while directing these activitiesat an intruding White-necked Crow. Some-times, however, the displaying birds weremore upright with the tail down and neckcurved down somewhat. The feathers of thebird’s head, throat, and back were elevated,and the white feather bases were clearlyexposed on the neck. Supplanted invaders, ifnot expelled from the area, sometimesresponded with similar visual and vocal dis-plays, directed at the resident birds. Johnston(1958) reported the Chihuahuan Ravenassuming a similar posture and exposing hid-den white on the neck during aggressive anddefensive behavior. Although Blake (1957)had suggested an epigamic function of theconcealed white neck feathers in the Chihua-huan Raven, Johnston (1958) was unable tofind support for this explanation in captiveand wild birds. Bowing and tail flaring havebeen reported for the Eurasian Rook duringterritorial conflicts (Coombs 1960).

Supplantation display. White-necked Crows per-formed a ritualized display after being sup-planted by another crow or other species. Thesupplanted crow moved away from the chas-ing bird and, perching, held its head below itsfeet, hung its wings down, fanned its tail, andcalled (bubbling calls). The neck was curveddownward with splayed neck feathers, show-ing their white bases. This position was some-times associated with a re-directed behaviorin which the crow hammered its perch withits bill or broke off a twig and carried it away.During more intense supplantation bouts

118


(e.g., multiple, intraspecific), the harassedcrow broke off nearby twigs for up to 1.5 min.Thereafter, the alien flew with a twig in its billand when it was 40–90 m from the aggressor,transferred the twig to its feet, dropped it inmid-flight, and flew into dense forest.

Aerial displays. White-necked Crows occasion-ally interrupted nest building to circle over thenest area while calling with caw’s. Birds soaredto heights of 50–200 m before dropping backto the forest.

Attacks on some large birds (crows, vul-tures, hawks) involved complex aerial displays.Crows chased the intruders in strong flapping,spiraling flights, sometimes to altitudes wherethe birds were barely visible to the human eye.During these ascending chases, crows calledvigorously with high-caw’s. If these chasesfailed in expelling the intruder, the crows flewabove and dove on the intruder, sometimesstriking the invader with their feet. After asuccessful eviction of an intruder from its ter-ritory, the resident flew to its nest area,frequently giving an aerial display, whereinit half raised its wings above its back in a“V,” momentarily held them stationary inthat position, dropped through the air forseveral meters, then gave a few strong flapsand repeated the display, dropping closer tothe forest canopy with each display. When thecrow was over its nest area, it lowered itslegs, elevated its wings and tail, and droppedto the nest in a series of parachuting glides.Week-woo calls were given during thedisplay. Sometimes crows descended rapidlywith wings 1/2 to 2/3 closed, varying thewing position to control their descent, directlyinto the forest. The aerial display was typicallyfollowed by perched crows calling withhigh-caw’s. Coombs (1960) described dihedralflights and glides by Eurasian Rooks andCarrion Crows, with some elements similarto the aerial display of the White-neckedCrow.

Greeting display. An incoming crow often gavea bubbling call as it approached its mate or nestsite. After landing, the pair performed amutual bowing display, with tail flips, and tailand wings partially spread. The birds thentouched bills and allopreened.

Allopreening. White-necked Crows displayedmutual allopreening between pair membersand, rarely, among other crows. This behaviorusually followed a greeting display. Thepreened individual loosened its feathers,bowed its head, and held its wings loose at itssides. The white of the neck feather bases wasvisible during allopreening. The preened birdfrequently reciprocated and preened its mate’sneck. This may be what Dod (1978, 1992)reported as courtship behavior. Kilham(1989), however, noted that other species ofCorvus clearly allopreen with neck feathersraised outside of the breeding season and out-side of a courtship context. Blake (1957)reported Chihuahuan Ravens also show theotherwise hidden white bases of the neckfeathers during courtship displays. Allopreen-ing has been reported for several species ofCorvus (e.g., Lorenz 1931, Skead 1952, Lamm1958, Coombs 1960, Gwinner 1964, Witten-berg 1968).

Twig gathering. After gathering a twig for itsnest, a White-necked Crow occasionallybowed its head down below its feet, then heldthat position for 5–15 s before flying to itsnest.

Food exchange. I observed food exchangesbetween adult crows from courtship throughthe post-fledging period. A crow (individual“A”) silently delivered the prey in its bill to itsperched mate (“B”). B sometimes performedlow intensity wing-fluttering, then quietlyreceived the prey in its bill, moved 1–10 maway after 5–20 s, and ate the prey, fed it tonestlings, or cached it nearby.

119

WILEY

FOOD, FORAGING, AND DRINKING

Depending upon season and locality, evenindividual species of crows may occupy vari-ous feeding niches; e.g., Common Raven hasbeen described as primarily a scavenger insouthwestern Virginia (Harlow et al. 1975),omnivorous in the Canary Islands (Nogales &Hernandez 1994), nest and chick predators inNorway (Byrkjedal 1987, Jacobsen & Ugelvik1992), Oregon (Littlefield 1995), and Mani-toba (Evans 1970), feeding on cereal grains insouthwestern Idaho (Engel & Young 1989),

small vertebrates in Oregon (Stiehl & Traut-wein 1991), and invertebrates (summer) andplant materials (autumn and winter) in theCanary Islands (Nogales & Hernandez 1997).Some species or populations have been con-sidered specialists (e.g., Hooded Crow, Got-mark et al. 1990), whereas others areconsidered generalists (Common Raven,Nogales & Hernandez 1994, 1997). WestIndian crows occupy broad feeding niches(Gosse 1847, Cruz 1972, Goodwin 1976,Lack 1976, Garrido & Kirkconnell 2000).White-necked Crows are omnivorous and

TABLE 1. Food items observed taken by adult White-necked Crows foraging at Los Haitises and Peder-nales, Dominican Republic, 1976, 2000, 2001, and 2002.

Items observed Number of observations Percent of observationsPlant material Hispaniolan royal palm (Roystonea hispaniolana) Cupey (Clusia rosea) Masa (Tetragastris balsamifera) Fourleaf buchenavia (Buchenavia capitata) Bullytree (Pouteria multiflora) Palo de Hierro (Ixora ferrea) Bastard redwood (Chrysophyllum argenteum) Urban's holly (Ilex riedlaei) Bulletwood (Manilkara bidentata) Rough strongwood (Bourreria succulenta) Tietongue (Coccoloba diversifolia) White pricklyash (Zanthoxylum martinicense) Unidentified plants Total plantsAnimal material Common green treesnake (Uromacer oxyrhynchus) Unidentified snakes Haitian giant anole (Anolis ricordii) Dominican giant anole (Anolis baleatus) Unidentified Anolis Unidentified frogs Nestling Bananaquit (Coereba flaveola) Nestling Plain Pigeon (Patagioenas inornata) Nestling Scaly-naped Pigeon (Patagioenas squamosa) Crustacean Snails Total animals Total items

13246228451726134133

15221351231641174

7.513.83.41.116.12.32.90.64.01.13.40.619.576.4

0.62.91.11.17.52.90.61.11.70.63.423.6

120


have been reported feeding on a variety offood types, including fruits (Beck 1916, Wet-more 1916, Wetmore & Swales 1931, Dod1978, Biaggi 1983), seeds (Wetmore 1916),grains (Dod 1978, Biaggi 1983), bird’s eggsand nestlings (Wetmore 1916; Dod 1978,1992), insects (Dod 1978, Biaggi 1983), smallreptiles (Biaggi 1983), and Eleutherodactylus

frogs (Wetmore 1916). Esquemeling (1684–1685) noted that “Their ordinary food is theflesh of wild-dogs, or the carcases of thosebeasts the buccaneers kill and throw away.”

I observed White-necked Crows feedingon all reported food categories (Tables 1 and2). Small items (e.g., invertebrates, smallamphibians) were probably more common

TABLE 2. Food items brought to nests by adult White-necked Crows, Los Haitises and Pedernales,Dominican Republic, 1976, 2001, and 2002.

Items Number of items delivered (%)

Observed delivered Remains foundPlant material Hispaniolan royal palm (Roystonea hispaniolana) Cupey (Clusia rosea) Bullytree (Pouteria multiflora) Bastard redwood (Chrysophyllum argenteum) Urban's holly (Ilex riedlaei) Coccoloba sp. Tietongue (Coccoloba diversifolia) Bulletwood (Manilkara bidentata) Smooth manjack (Cordia nitida) Camasey (Miconia sp.) Sweet acacia (Acacia farnesiana) Unidentified plants Total plantsAnimal material Common green treesnake (Uromacer oxyrhynchus) W-headed racer (Ialtris dorsalis) Unidentified snakes Haitian giant anole (Anolis ricordii) Dominican giant anole (Anolis baleatus) Unidentified Anolis Unidentified Ameiva Hispaniolan giant eleuth (Eleutherodactylus inoptalus) Unidentified frogs Nestling Bananaquit (Coereba flaveola) Nestling Patagioenas spp. Nestling passerines Columbid eggs Walking sticks (Orthoptera) Beetles Beetle larvae Total animals Total items

10 (3.5)53 (18.5)19 (6.7)4 (1.4)

—2 (0.7)

—5 (1.8)

——

4 (1.4)41 (14.4)138 (48.4)

14 (4.9)2 (1.7)3 (1.1)7 (2.5)12 (4.2)27 (9.5)1 (0.4)5 (1.8)22 (7.7)5 (1.8)5 (1.8)12 (4.2)5 (1.8)7 (2.5)12 (4.4)8 (2.8)

147 (51.6)285

12 (18.2)7 (10.6)7 (10.6)2 (3.0)3 (4.5)

—2 (3.0)1 (1.5)1 (1.5)1 (1.5)

—9 (13.6)45 (68.2)

1 (1.5)—

3 (4.5)2 (3.0)3 (4.5)2 (3.0)

—1 (1.5)4 (6.1)

————

1 (1.5)4 (6.1)

—21 (31.8)

66

121

WILEY

than I report, because they were difficult toidentify from a distance and were usuallypassed quickly to chicks before I could deter-mine identity. Like Wetmore (1916), I foundthat adult crows consumed mostly plantmaterials (76.4% of my observations of forag-ing crows; Table 1). Nevertheless, animalswere more prevalent (51.6%) amongitems delivered to nestlings, compared withmy observations of items taken by foragingcrows (χ2 = 35.07, df = 1, P < 0.0001; Table2). Although I observed carcasses (dogs,livestock) within some of the rural areaswhere crows occurred in the DominicanRepublic, no White-necked Crows wereobserved feeding on carrion. Palm Crows,however, were observed feeding at carcasses(contra Madge & Burn 1994) along with Tur-key Vultures.

Interviews of older woodsmen providedinformation on native plant species eaten byWhite-necked Crows in Puerto Rico. Severalpeople reported crows fed on the fruit of thePuerto Rican royal palm (Roystonea borinquena);other species included sierra palm (Prestoeamontana; fruit), candletree (Dacryodes excelsa,fruit), mucilage manjack (Cordia sulcata; fruit),and doncella (Byrsonima coriacea; fruit). Somewoodsmen reported finding seeds of severalplant species in and under nests, as did I.White-necked Crows, similar to some othercorvids (e.g., Common Raven; Nogales &Hernández 1994), are undoubtedly importantseed dispersal agents.

Although White-necked Crows descendedto the ground to forage on crops, in foreststhey were strictly arboreal. Non-breedingcrows formed small foraging flocks thatranged widely in search of food. Breedingpairs spent most of the day within their terri-tories and foraged primarily within thoseareas, although individuals (especially males)were unaccounted for during long periodswhen they could have been foraging else-where. Foraging crows often worked in pairs

as they systematically moved through theupper- and mid-sections of trees, where theysearched up and down the trunk andbranches investigating hiding places for prey.They were particularly active among vines,bromeliads, and orchid masses, where theyprobed for invertebrates, reptiles, andamphibians. Crows were observed to hang onthe vertical cliff faces of karst areas and probein the pock-marked face for prey while main-taining balance by flapping their wings. Crowsflew to fruit masses on Hispaniolan royalpalms, hanging on the side of the cluster, withbody horizontal or vertical (head up), andplucked fruits. Crows held hard objects (e.g.,snails, large seeds and fruits) in their feet andhammered them open with their bills. I occa-sionally saw crows hammering on deadbranches and trunks, as well as chipping awayat bark on live trees, apparently to extractinsects. On Isla Saona, I watched severalWhite-necked Crows moving systematically,but as individuals, from nest to nest in aWhite-crowned Pigeon colony, where theypreyed on the pigeon eggs and squabs. Thecrows were so thorough in this nest depreda-tion that in some years local residentsbelieved crows had caused the failure of thepigeon colony. Vargas & Arendt (1978) notedWhite-necked Crows were common on IslaSaona, where the pigeons were breeding inlarge aggregations, but were not found therewhen the pigeons were not breeding. Simi-larly, Cherrie (in Wetmore & Swales 1931)reported crows opportunistically bandingtogether in immense flocks to exploit theregional availability of fruits. Other corvidsare known to exploit concentrations of prey(eggs, nestlings) in nesting colonies of birds(e.g., Common Ravens; Parmelee & Parmelee1988, Gaston & Elliot 1996).

I observed crows caching food (plant andanimal) in tree cavities and crotches, and inbromeliads. The birds sometimes returned totheir caches, but often the food was not

122


retrieved. Such food hiding behavior is com-mon among corvids (reviewed by Turcek &Kelso 1968; see also James & Verbeek 1985,Verbeek 1997, Heinrich 1999).

I saw an adult White-necked Crow capturea small (15 cm) snake (Uromacer oxyrhynchus) ona tree branch 5 m from the crow’s nest. Theadult crow had been perched an additional 5m from the nest. It flew 10 m, grabbed the

snake in its bill, pinned it between the branchand its foot, then tore pieces of flesh from thesnake. After it had eaten about half of theprey, it took the remainder to its nest, where itfed it to one chick. The other adult crow flewto the site where the snake had been capturedand thoroughly searched the area. Larger liz-ards (e.g., Anolis ricordii) were handled andeaten in a fashion similar to that described forthe snake.

Standing water was generally not availablein Los Haitises, but temporary pools did formafter rains. Nevertheless, I did not observecrows coming to the ground to drink. Rather,they took water from cups in leaves, from theaxils of bromeliad bracts, and from bowlsformed in tree crotches.

MOVEMENTS AND FLOCKING

White-necked Crows made regular flights dur-ing the day (Fig. 9). Whereas directions ofmidday (10:00–14:00 h EST) flights at LosHaitises were random (R = 7.11, N = 33, P >0.05; Rayleigh test), morning (> 10:00 h; R =69.11, N = 97, P < 0.001) and late afternoon–evening (14:00 h to dusk; R = 97.87, N = 121,P < 0.001) flights were not uniformly distrib-uted. The mean compass direction of flightsbefore 10:00 h was 178°30’, whereas flightsafter 14:00 h had a mean direction of 04°09’;i.e., crows flew south in the morning and backnorth in the late day. Midday flights repre-sented local movements within the study area.Breeding crows infrequently made longflights, although some (non-breeding?) indi-viduals continued to do so through the nest-ing period. I believe these movements were toforaging sites, probably crops about 3 kmsouth of my study area, where I observedgatherings of crows.

Verrill & Verrill (1909) and Verrill (1926)reported that White-necked Crows in theDominican Republic formed immense feed-ing flocks in lowland swamps, which the

FIG. 9. Flight patterns of White-necked Crowsduring three time periods, Los Haitises, DominicanRepublic, 1976: A. 05:00–09:59 h (N = 97), B.10:00–13:59 h (N = 33), C. 14:00–18:59 h (N =121). Scale on horizontal axis is frequency offlights toward compass bearings on perimeter ofouter circle.

123

WILEY

crows visited daily from their roosts in themountains. In eastern Dominican Republic,Beck (1916) observed hundreds of crowsdescending from mountains to forage in low-land swamps by 10:30 h, then returning tothose mountains from 14:00 to 16:00 h. Asrecently as 21 March 1997, a flock of at least300 White-necked Crows was observed inLos Haitises (Keith et al. 2003). Wetmore &Swales (1931) noted nightly roosting congre-gations of White-necked Crows in Haiti,where the birds moved from roosts in earlymorning and returned at night. Dod (1978)also reported distant movements wherein thecrows foraged in lower sites in the mornings,then flew to regular roost sites in trees in thehigh mountains. Wetmore (1916) noted longdistance flights by White-necked Crows ineastern Puerto Rico that were related to

weather. On days when it was cold and rainyon the summit of El Yunque, crowsdescended into the warmer valleys. When theweather cleared, they moved back to thehigher peaks. Along the northern shore ofLago Enriquillo, Dominican Republic, Iwatched crows form pre-roost flocks in Junethrough September. Flights from the stagingsites were made en mass, with as many as c.60 crows flying into high mountain valleys tothe north. Communal roosting and pre-roost-ing are common among corvids (e.g., Engel &Young 1992). American Crows have beenreported forming pre-roosting aggregationsbefore flying into a night roost, with theaggregation sites perhaps serving as informa-tion centers for location of either daytime for-aging areas or nighttime roosts, as well aslowering predation risk (Moore & Switzer

FIG. 10. Activity areas of three White-necked Crow pairs, Los Haitises, Dominican Republic, 1976. Dotsrepresent nest sites: # 1 = H1976 # 1, # 2 = H1976 # 2, # 4 = H1976 # 4. Shaded areas represent ridgesand uplands.

124


1998). Common Ravens formed large com-munal roosts, which varied in number ofindividuals seasonally (Engel et al. 1992),although Heinrich et al. (1994) found indi-viduals in a raven population showedconsiderable independence of one anotherwith no indication of flock cohesiveness.Hooded Crows gathering in pre-roostsperched in a highly aggregated and exposedgroup that did not forage (Hansen et al. 2000).Hansen el al. (2000) suggested the pre-roostgathering had a function of maximizing theprobability of finding rewarding food sites thenext day.

During the breeding season, White-necked Crows usually associated as pairs.Non-breeding, yet paired, birds formed smallgroups that occupied areas peripheral tonesting areas. Breeding crows occasionallycongregated with other breeding and non-breeding crows in moderate-sized groups(up to 20 birds). A flock of 18 crows formedat 08:00 h on 10 April 1976. The birds arrivedon a hilltop as singles (N = 4) or pairs (7),and perched within 30 m of one another intrees. There were continual supplantationsand calling with complex high-low gargles.All of the crows slowly dispersed in theirrespective pairs or as singles in various direc-tions after about 5 min. Two birds made mid-air attacks on a third crow as the group dis-banded. Groups of crows were commonlyseen after the breeding season, when groupscontained adult pairs, as well as some fledg-lings. The paired adults frequently allo-preened. Chasing within the groups wascommon.

I observed sentinel behavior amongWhite-necked Crows, particularly when flocksfed on crops on or near the ground. Foragingunder those circumstances probably placedbirds at greater risk to predation, especiallyfrom humans. As in other corvids, theincreased risk probably favored the presenceof sentinels (e.g., Maccarone 1987).

ACTIVITY AREA AND TERRITORY

Core activity areas of members of threebreeding pairs averaged 9.8 + 3.7 (range =7.6–11.9) ha (Fig. 10). One or both members,however, occasionally made long forays,where I was unable to determine distances.

Several species of corvids have beenreported as defending territories (reviewed byKilham 1985a). Although they are somewhatgregarious in feeding and roosting, White-necked Crows maintain strict breeding territo-ries (Dod 1978). Territories were defendedyear-round, but less vigorously in the non-breeding season than during the nestingperiod. The mean distance among the threenests I measured in Los Haities was 392 +98.3 (range = 282–620) m. White-neckedCrows were highly defensive of nestingareas and chased intruders with direct sup-plantation flights and vocalizations. Crowsnoisily chased other birds, and dove at them,occasionally striking even large aggressive rap-tors (Red-tailed Hawk, Ridgway’s Hawk). Iobserved cooperative attacks by several crowson other species more often in the non-breed-ing season than when pairs were nesting (χ2 =4.71, df = 1, P = 0.03). Typically, pairs ofcrows attacked an intruder in series as it flewthrough each of the residents crows’ territo-ries. But if the alien landed, or began soaring,members of two or more pairs (mean = 5.0 +0.93 individuals; N = 140 bouts) mobbed theintruder. When perched, the crows orientedtoward the intruder, tail flipped, and calledwith loud caw’s. Mobbing of perched Red-tailed Hawks that remained in the crows’activity area continued for up to 1 hour.Neighbors (up to 4 pairs) were involved incooperative attacks on other species (Red-tailed and Ridgway’s hawks, Turkey Vultures)in 61% (N = 179) of interspecific conflicts.

Intruding White-necked Crows were vig-orously chased from territories by residents.Both resident sexes defended territories

125

WILEY

against intruding conspecifics and nests wereleft unguarded during the chases. At theapproach of the defending residents, aliensusually left the area. Residents pursued thefleeing crow with a close tail chase. When theintruding crow did not leave with the resi-dents’ approach, the territory holders landednext to the alien and performed an antagonis-tic display directed at the intruder. Theintruder, when supplanted, sometimes movedonly a short distance, then perform a head-down, tail-fanned display, while giving a hic-gu-gik-gu call. The intruder either flew from thearea or the resident(s) made additional shortsupplantation flights before the intruder left.Less intense threat displays consisted of cawand bubbling calls, and tail flipping.

Most chases and supplantations did notinvolve physical contact. Occasionally, how-ever, pursuing crows struck fleeing birds onthe back with their feet. Fleeing crows fendedoff the aggressors by turning upside downand presenting their outstretched talonstoward the incoming bird. After turning backfrom the chase, the territorial birds per-formed an aerial display and gave week-woovocalizations. At the nest area, both residentbirds gave bubbling calls.

Different species evoked initial responsesby White-necked Crows at distinct distancesfrom the crow nest [P < 0.05 for all compari-

sons, except White-necked Crow vs Sharp-shinned Hawk (Accipiter striatus), P = 0.35;unpaired t-test; sample sizes as in Table 3].Sharp-shinned Hawks (N = 15 defenses) elic-ited territorial defense by nesting White-necked Crow pairs from the farthest distances(mean = 111 + 41.8 m), followed by alienWhite-necked Crows (mean = 102 + 36.9 m;Table 3). Other raptors (Red-tailed Hawk:mean = 90 + 16.5 m; Ridgway’s Hawk: 47 +11.5 m; Turkey Vulture: 31 + 4.9 m) appar-ently caused greater concern by the nestingcrows than did intruding Hispaniolan Parrots(Amazona ventralis; mean = 20 + 6.8 m) orpigeons [primarily Plain Pigeon (Patagioenasinornata) and Scaly-naped Pigeon (P. squamosa);collectively mean = 8 + 3.2 m]. Sharp-shinned and Ridgway’s hawks were usuallychased from the crow nesting area. Neither ofthese hawks was mobbed by several crowfamilies to the same extent as were Red-tailedHawks. One White-necked Crow pair built itsnest within 30 m of an active Ridgway’s Hawknest. At that territory, I observed several sup-plantations and chases of hawks pursuingcrows and crows chasing hawks during earlynest-building. Later in the breeding season,however, few encounters were observed.Nevertheless, when an alien immature Ridg-way’s Hawk entered that crow pair’s nestingterritory, it was immediately and vigorously

TABLE 3. Distance of initial response by adult nesting White-necked Crow to territorial intruders at threecrow nests, Los Haitises, Dominican Republic, 1976.

Statistics Distance (m)/species

Ridgway’sHawk

White-necked Crow

Red-tailed Hawk

Sharp-shinned Hawk

Turkey Vulture

Hispaniolan Parrot Pigeonsa

MeanSDNRange

4711.530

20–70

10236.9309

40–225

9016.584

45–120

11141.815

60–225

314.966

20–40

206.838

5–30

83.216

5–15

aPigeons = Scaly-naped Pigeon (Patagioenas squamosa), Plain Pigeon (P. inornata), and White-crownedPigeon (P. leucocephala).

126


chased from the vicinity by the crows.Although the resident female Ridgway’s Hawkperched as close to the crow’s nest as the alienjuvenile hawk, she was not attacked by theresident crows.

Resident crows aggressively chased Tur-key Vultures whenever the vultures passedthrough the crows’ territory. In the air, thecrows struck the vultures with their feet.When the vultures landed within the crows’territory, they were driven off with a supplan-tation flight after the crow had first landednear the vulture, tail-flipped, and sometimescalled with caw and bubbling calls.

Crows and Hispaniolan Parrots nestedclose to one another in Los Haitises and Iobserved frequent interactions between thesespecies. Each species showed dominance overthe other near their respective nests. Parrotswere chased by crows, which gave caw or bub-bling calls during pursuits. A pair of parrotsthat landed in a White-necked Crow nest treewas supplanted by a direct flight by an adultcrow, which had been perched 10 m away. Theparrots immediately left the area. The crowsoared low over the nest tree, returning to thetree with its legs dangling, and wings elevatedin a glide. As it glided to its nest, the crowcalled with a week-woo call, then gave a raspy,guttural gurr. Parrots supplanted crows with adirect (usually silent) flight; rarely a parrotstruck a crow with its feet during aggressiveencounters. Parrots sometime gave take-offcalls and flight bugles as they flew towardintruding crows (Snyder et al. 1987).

Immediately around their nests, White-necked Crows were aggressive toward colum-bids. Pigeons were chased from the crow nestarea in silent supplantations or the crow(s)gave raspy, short, bubbling calls. Pigeons flyingthrough the nest area were occasionally pur-sued by crows.

Based on these observations of crowdefenses against conspecifics and other spe-cies, I estimated the average territory size of

three nesting pairs was 5.5 + 5.2 (range = 1.1–11.3) ha. That estimated territory size is mod-erate compared with those reported for othercorvid species; e.g., 0.5 ha – NorthwesternCrow (Corvus caurinus) (Butler et al. 1984), 4 ha– Little Raven (C. mellori) (Rowley 1967), 27 ha– Carrion Crow (Wittenberg 1968), 60 ha –Black Crow (C. capensis) (Skead 1952).

Both sexes of the White-necked Crowattacked intruders equally (χ2 = 0.443, P =0.513, N = 207; Fisher exact test). In contrast,male Northwestern Crows performed 81% ofterritorial defense (Butler et al. 1984).

NEST BUILDING

In Los Haitises, I first observed crowsnest building on 24 January 1976, althoughsustained building did not begin until 24 Feb-ruary. Nest building at Miches also began inFebruary, although there a pair was observednest building as late as 28 April. Nest buildingactivities of White-necked Crows variedthrough the day (F0.05(1),3,16 = 19.42, P < 0.001;one-factor ANOVA) and were greatest atmid- to late morning (09:00–11:59 h) and lateafternoon to evening (15:00–18:59 h; Fig. 11).Nest materials were gathered 3–80 m (mean =33.2 + 21.6 m; N = 34 trips) from the nest.All nest material was gathered from trees;although twigs were abundant on the forestfloor, I saw no birds descend to gather materi-als there. While gathering twigs, adults (bothsexes) occasionally called with loud gutturalweeak-weeak-weeah vocalizations. White-neckedCrows called (caw, wag) in 32% of my observa-tions (N = 81) as material was delivered tonests, but otherwise entered the area silently.During early nest building (week one: 24–25January, Los Haitises), crows occasionally per-formed a bowing display after plucking a stickfrom a tree. With the twig in its bill, the crowbowed its head below its feet, held it there upto 15 s, then stood upright for about 50 sbefore flying to its nest. The bird usually did

127

WILEY

not fly directly to it, but landed 9–18 m fromthe nest where it walked among the branches,flipping its tail, for a few seconds, apparentlysurveying the area for predators, then flewdirectly to the nest. Both adults collectedmaterials and built the nest; at one nest(H1976 # 1), individual “A” (sex undeter-mined) made 64% (N = 28) of the nest-build-ing trips; at the H1976 # 2 nest, individual“A” made 71% (N = 7) of the deliveries.Coombs (1960) reported male EurasianRooks gathered most materials and con-structed nests.

At the height of nest-building activity, thecollecting adult was at the nest for an averageof 36 s (range = 10–120 s; N = 34). Thematerial brought to the nest was eitherworked into the structure by the member whohad been laboring at this task while its matecollected material or, if both birds were gath-

ering, by the member making the delivery.Fresh nest materials were delivered to the nestthrough the mid-nestling stage, possibly func-tioning to renew the parasite repellency of thenest as in some species (e.g., Wimberger 1984,Clark et al. 1990, Petit et al. 2002).

After placing materials, crows left togather more material, giving loud calls (caw,gauch) in 80% of my observations (N = 75).On occasion, an adult would perform a post-delivery flight over the nest after depositingthe nest material. The adult circled low overthe nest tree, calling with caw’s, then flew tothe twig-collecting site.

Construction at nests was slow and inter-mittent for up to four weeks before intensivebuilding began. Then, two crow nests Iclosely watched took four and five days,respectively, to complete. These periodswere comparable to nest-building times

FIG. 11. Time of nest building by three pairs of White-necked Crow, Los Haitises, Dominican Republic,1976.

128

129

WH

ITE-N

ECK

ED

CROW

ECO

LOG

Y A

ND

CON

SERVA

TION

TABLE 4. Characteristics of 12 White-necked Crow nests, Los Haitises (H), Barahona (B), and Pedernales (P), Dominican Republic, 1976, 1996, 2000,2001, and 2002.

Nes Support for nest

H19H19H19H19H19H19H20H20P20P20B20B20

n arean areaee

Clusia branchesClusia branches

Clusia branches & vinesUpper branches

Clusia roseaa

Clusia roseaa

Clusia roseaa

Clusia roseaa

Upper frond axilsUpper frond axilsUpper frond axilsUpper frond axils

aHosbNesc“Tr

t Tree species Tree height

(m)

Nest height

(m)

Tree diameter at nest(cm)

DBH (m)

Distance nest from center (m)

Location

76 # 176 # 276 # 376 # 496 # 196 # 202 # 102 # 200 # 101 # 102 # 102 # 2

Clusia roseaa

Clusia roseaa

Buchenavia capitatab

Buchenavia capitataClusia roseaa

Buchenavia capitatab

Guarea guidoniaBuchenavia capitatab

Roystonea hispaniolanaRoystonea hispaniolanaRoystonea hispaniolanaRoystonea hispaniolana

30.321269.0182518139.210.215.418.6

28.820238.51518138.98.39.212.315.4

25.419.318.519.814.518.421.620.329.530.224.423.8

?c

?c

1.30.9?c

1.90.81.50.60.60.50.7

0.91.70.70.20.60.80.81.00.10.10.20.1

SE slopeSE slope

NW slopeE slope

NW slopeSE slopeSE slopeN slope

Woodlot in urbaWoodlot in urba

Forest edgForest edg

t tree completely gone, with only formerly dependent Clusia remaining.t built in Clusia, which dominated upper portion of host tree.unk” consisted of multiple stems of the dependant Clusia.

WILEY

reported for American Crows by Kilham(1984; 5–9 days), but were shorter thanthe average of 13 days reported by Emlen(1942).

Although cliffs with pot holes and ledgeswere available in Los Haitises, all crow nestswere placed high in tall trees or, in Pederalesand Barahona, in palms (mean tree andpalm height = 17.8 + 6.9 m, range = 9.0–30.3m; mean nest height = 15.0 + 6.5 m, range =8.3–28.8 m; N = 12), with nest placementaveraging 84.4 + 9.5% (range 68.5–95.2%)of the tree or palm’s height. Sites selecteddid not differ in height of tree versuspalms (mean tree height = 20.0 + 7.0 m,range = 9.0–30.3 m, N = 8; mean palm height= 13.4 + 4.4 m, range = 9.2–18.6 m, N = 4; t= 2.01, df = 9, P > 0.05). Nest sites weretypically in emergent trees or palms. Nests intrees (mean nest height = 16.9 + 7.0, range =8.5–28.8 m; N = 8; Table 4) averaged slightlyhigher than those in palms (mean nestheight = 11.3 + 3.2 m, range = 8.3–15.4 m, N= 4; t = 1.90, df = 9, P > 0.05), likely relatedto greater average tree height compared topalm heights. Nest placement in palms andtrees averaged 84.3 + 9.5% of tree height,with no difference between heights at whichnests were built in trees (mean = 83.6 +11.3%, range = 68.5–95.2%, N = 8) andpalms (mean = 85.8 + 5.3%, range = 79.9–90.3%, N = 4; t = -0.45, df = 9, P > 0.05).Others also reported White-necked Crownests placed high in trees (Wetmore 1916,Wetmore & Swales 1931, Dod 1978, Biaggi1983).

Nests were bulky platforms in crotches orsupported by limbs of dense Clusia or vines.They were constructed of branches (3–13mm diameter), with a lining of orchid andother leaves, fine twigs, bromeliad bracts, andmoss. Nests in palms included considerabledried palm frond material among the twig andstick structure. Four nests averaged 56.6 + 2.4(range = 53.3–61.1) cm in diameter and 55.1

+ 3.8 (range = 47.4–59.3) cm in depth. Theshallow cup averaged 10.1 + 1.3 (range = 7.9–12.3) cm deep.

Two closely watched nests were built inpalms within 2 m of active Palmchat (Dulusdominicensis) nest colonies. Palmchats consis-tently gave alarm calls, scattered from the nesten masse, and displayed excited behavior withthe arrival and departure of nesting crows.Crows occasionally took nest twigs from thePalmchat colony, either dropping the materialor carrying it to their nest. Crows alsoappeared to be probing the Palmchat nestentrances, although I observed no depreda-tions of contents. Nevertheless, Palmchatsbecame increasingly excited as crows probedamong their nest colony.

Although “helpers” have been reportedfor other corvids (e.g., American Crow: For-bush 1927, Good 1952, Kilham 1984, 1985b,Caffrey 2000; Carrion Crow: Charles 1972;Northwestern Crow: Verbeek & Butler 1981),I found no evidence of this behavior atnests of White-necked Crows. Similarly, Idetected no extra-pair birds (other thanneighboring breeding pairs) assisting in terri-torial defense.

NESTING CHRONOLOGY

Egglaying at four nests (H1976 # 1, H1976 #2, H1976 # 3, H1976 # 4) at Los Haitisesoccurred from 27 February to 10 March. Atthe nest (H1976 # 1) I watched most inten-sively, egglaying began on 6 March 1976, 8days after the nest was completed (27 Febru-ary). The nest held four eggs on 9 March.Egglaying at daily intervals appears to be ageneral trait for the genus Corvus (Holyoak1967, Wittenberg 1968, Butler et al. 1984). Apair (H1976 # 3) whose nest fell in a windstorm, built a new nest 15 m from the firstsite and began laying eggs about 4 April, 25days after its first clutch was lost. The incuba-tion period lasted about 18–22 days and the

130


nestling period was approximately 35–44 days.Common Ravens have a similar incubationperiod of about 21 days (Stiehl 1985). Ameri-can Crows fledge at 30–34 days of age (Igna-tiuk & Clark 1991). Although I had fewopportunities to observe fledglings, I believeadults continued to attend them for at leasttwo weeks after young birds fledged. Iobserved adults carrying food to fledglingsnear the nest tree (radius of about 30 mfrom nest) for 14 days after chicks hadfledged. Adults were characteristically silentduring food transfers, but nestlings gave softnaw calls. The breeding season (excludingreplacement nests) lasted about 94 days;i.e., 24 February to 28 May. I did not findevidence of second clutches. In Haiti, nestswere reported on 24 April and 2 May (Wet-more & Swales 1931, Bond 1947). Biaggi(1983) reported the White-necked Crownested from March to May in Puerto Rico.Wetmore (1916) found nests containingeggs and others with well-grown chicks inMarch in lowland Puerto Rico, suggesting thatthe crow may begin breeding earlier at lowerelevations.

EGGS

Clutch size averaged 3.9 + 0.4 (range = 3–4)eggs at the seven nests I inspected at clutchcompletion. Another nest contained threeeggs when it fell in a storm during the egglay-ing period (Table 5). Dod (1978) reportedclutch size in the Dominican Republic asthree to four eggs.

Twelve eggs (from 3 nests) I measuredaveraged 42.3 + 0.42 (range = 40.3–44.6) mmin length and 29.1 + 0.41 (27.5–31.6) mm inbreadth. Gundlach (1874) reported the size ofa White-necked Crow egg from Puerto Ricoas 44 x 29 mm. The 12 eggs I weighed aver-aged 30.3 + 0.34 (range = 28–32) g at aboutmid-incubation.

The egg is hazel (varying from pale green-ish-blue to greenish-brown) in ground color,and is speckled with maroon to brownthroughout, but more heavily on the roundedend. Dod (1978) described the egg as palegreen, marked with maroon. Gundlach(1874) noted that the coloration of the White-necked Crow’s egg resembled that of theCuban Crow, which is greenish with spots of

TABLE 5. Outcome of eight White-necked Crow nesting attempts, Los Haitises (H) and Pedernales (P),Dominican Republic, 1976, 2000, and 2001.

Nests Number

Eggs Chicks hatch Older chicks Chicks fledgeH1976 # 1H1976 # 2H1976 # 3H1976 # 4P2000 # 1P2001 # 1H2002 # 1H2002 # 2Mean + SDN

443a

44443

3.8 ± 0.58

33044443

3.6 ± 0.5b

7

33034432

3.1 ± 0.7b

7

33034432

3.1 ± 0.7b

7

aNest falls in wind-storm during egglaying/incubation.bNests with competed clutches.

131

WILEY

brownish violaceous (Garrido & Kirkconnell2000).

NESTLINGS

Of the eight nests I watched closely, one fellin a windstorm during the incubation stageand the other seven hatched 25 chicksfrom 27 eggs (0.93 hatching rate; Table 5).All chicks at four nests fledged, whereasthree nests lost one chick each betweenhatching and fledging, for an overall fledgingsuccess of 81.5% (N = 22/27) of eggslaid at the seven successful nests; produc-tivity was 2.8 + 1.3 young per nest and 3.1 +0.7 young per successful nest (Table 5). Atthe four nests where four chicks hatched,the first two hatched on the same day,but chick # 3 hatched on the second dayand the fourth chick hatched two dayslater. Asynchronous hatching has beenreported for several corvids, includingChihuahuan Raven (Haydock & Ligon1986), Northwestern Crows (Butler et al.1984), Eurasian Jackdaws (Corvus monedula,Lockie 1955), and Carrion Crows (Wittenberg1968).

Hatchlings were naked with charcoal-col-ored skin. The rictus was bright fuscia,whereas the gape was bright red. Their eyesremained closed at least through the sixth dayafter hatching. Primary sheaths began toemerge on day six. The six-day-old chickswere quite helpless and gave soft creakingcalls when I visited the nest. Average weightsof chicks were: Day 1: 43 g (N = 1), Day 3:60.3 + 3.9 g (N = 3, range = 55–66 g), Day 5:103 + 4.0 g (N = 2, range = 99–107 g), Day 6:112 + 3.0 g (N = 2, range = 109–115 g). Thechicks acquired a coat of charcoal down bydays 6–9. At the mid-nestling stage theflanges were cream colored, from the gape tonear the upper and lower mandible tips. Byage 17–22 days, the nestlings gave severalcalls. As the adult landed at the nest, the

chicks gave a low gargling call. They out-stretched their necks, lifted their heads, andopened their bills to the sky. While being fedby the adults, the chicks sometimes gavecreaking calls, which sounded like a rustydoor hinge (but rapidly repeated). Whenadults were absent from the nest vicinity,chicks at the mid-nestling stage remainedcrouched low in the nest bowl, with only thetops of their heads and part of the backs visi-ble above the rim. Chicks were occasionallyactive, autopreening and exploring nest mate-rial with their bills. When an adult was presentin the nest vicinity, mid-stage nestlings oftenexercised their wings and autopreened. Adultsallopreened nestlings at this stage. Olderchicks, when alone at the nest, alternated theiractivities among dozing, preening, and callingwith soft cawing calls while scanning the sur-roundings for the adults. At that age, chicksactively moved out on branches supportingand adjacent to the nest, flapping vigorously,to meet incoming adults; sometimes all chickswere vigorously begging from adults on theoutskirts of the nest. After receiving food, thechicks returned to the nest bowl, where theyoccasionally flapped their wings vigorously inexercise. As the birds matured, they movedfarther from the nest during exercise bouts,often when an adult was out of sight, flappingwings and hopping, but returned to the nestthereafter. By day 20, chicks were mostlyfeathered, although some charcoal-coloreddown remained on the head and body. Atfledging, the chicks’ eyes were a milky bluecolor (appearing dark gray from a distance)and their plumage was a dull black, lackingthe glossy sheen of adults. The bases of neckfeathers were light gray rather than white as inadults. The large, white “lips” appearance ofthe rictal flanges had been lost, and thebright fuchsia color of the gape had dulled toa pinkish-red. Fledglings, like adults, used anover-the-wing movement to scratch theirhead.

132


ADULT ATTENDANCE ANDBEHAVIOR AT NEST

I watched two crow nests from incubationthrough fledging for a total of 118.3 h (Table6). Adult attendance declined significantlyfrom the incubation through the late nestlingperiods (F0.05(1),3,10 = 38.09, P < 0.0001; one-way ANOVA). Although normally onlyfemale corvids incubate (Goodwin 1976, But-ler et al. 1984, Verbeek 1995), and Dod (1978)reported the female White-necked Crow per-formed all the incubation, I observed bothsexes sitting on eggs at the one nest (H1976 #1) I watched from a blind placed close enoughto note individual differences in adults. Oneof the pair members (“A,” sex not deter-mined), however, was on the nest more (89%)than the other (11%) in those incubationbouts when I was able to distinguish individu-als (N = 17.8 hours; Z = 1.83, P = 0.06, Wil-coxon paired-sample test). One adult(consistently “A”) remained on the nest over-night through late brooding. The other adultnormally roosted within 10–20 m of the nest.

During incubation and early nestling (days0–13) stages, “A” only left the nest for short(5–15 min) periods, usually when its materelieved it. During the incubation and early

nestling stages, at least one adult was on thenest 96.2% and 84.2% of observation time,respectively (t = 3.3, df = 1, P > 0.05; Table6). Adults normally left the nest during foodtransfers (within 3 m), although on 12 occa-sions (N = 229) at the H1976 # 1 nest, onebird (“B”) delivered food items to its mate atthe nest. When food was brought to the nestarea, the incubating bird flew to the incomingbird and, with mutual soft gik calls and tailflipping, quickly took the item. The attendingbird then flew a short distance and consumedthe food while the incoming bird flew to thenest and covered the eggs. After finishing thefood item, the bird returned to the nest andthe other adult flew off silently. At othertimes, “B” flew directly to the nest andassumed incubation duty, while “A” flew off,probably to forage and preen.

Although adult attendance remained highduring the early nestling period, the amountof time the nest was left unguarded (11.1%during early nestling stage vs. 3.6% duringincubation) or when one or both adults werein the vicinity of the nest (within 15 m;“guarding”) when not covering eggs or chicks(4.7% vs. 0.5%) increased above that duringincubation (Table 6).

By the mid-nestling stage (days 14–28),

TABLE 6. Adult White-necked Crow attendance behavior at two nests, Los Haitises and Pedernales,Dominican Republic, 1976 and 2000.

Stagesa No. observation periods

Time (h)

Observations One or both adults on nest

(%)

No. adult on or near (within 15 m) nest

(%)

Adult within 15 m of nest

(%)IncubationEarly-nestlingMid-nestlingLate-nestlingTotal

2255

21.019.043.834.5118.3

20.2 (96.2)16.0 (84.2)21.1 (48.2)10.4 (30.1)

0.8 (3.6)2.1 (11.1)19.3 (44.1)21.1 (61.2)

0.1 (0.5)0.9 (4.7)3.4 (7.8)3.0 (8.7)

aEarly nestling stage = days 0–13, mid-nestling stage = days 14–28, late nestling stage = days 29–44.

133

WILEY

adult nest attendance had declined to 48.2%(early vs. mid-nestling: t = 6.7, df = 1, P >0.05; incubation vs. mid-nestling: t = 15.9, df= 4, P < 0.0001), whereas the amount of timeadults remained in the vicinity of the nestincreased (Table 6). Attendance reached a lowpoint during the late nestling stage (days 29–44; adults on nest 30.1% of observed time;incubation vs. late nestling: t = 11.9, df = 4, P< 0.0001; early vs. late: t = 8.0, df = 4, P =0.001; mid vs. late: t = 3.99, df = 5, P = 0.01),with a slight increase (8.7%) in presence nearthe nest when not brooding. During mid andlate nestling periods, adult crows did notbrood the chicks, but cleaned the nest andpreened young when at the nest. Verbeek(1995) reported female Northwestern Crowsessentially ceased brooding chicks by day 15,when they participated fully in food gathering.The cessation of daytime brooding coincidedapproximately with the eruption of feathersfrom their sheaths, attainment of effectiveendothermy, start of maximum daily growthrate of the feathers, and point of inflection ofthe chicks’ growth curve.

Adult White-necked Crows fed nestlingsthroughout the day but feedings were morefrequent during the early morning and lateafternoon than at midday (U 0.05(2),8,8 = 96.5, P= 0.003, U 0.05(2),8,5 = 36.0, P = 0.004, respec-tively; Table 7). Both adults fed the young,

although occasionally one adult would passfood to its mate, who then carried it to thenest and fed the chicks. On several occasions,I observed both adults at the nest simulta-neously feeding the nestlings.

Larger food items were carried to the nestin the adult’s bill, whereas smaller items andmuch of the plant materials were delivered inthe adult’s sublingual pouch and regurgitatedinto the chicks’ mouths. Whole food was car-ried to the nest or nearby limb in the bill, thenbroken apart with heavy blows of the billwhile the item was held in the bird’s feet.

Although mean food deliveries to nest-lings per hour were consistently higher atfour-chick nests compared with three-chicknests, feeding rates at the latter did not differfrom those at four-chick nests (early nestlingperiod, t = -1.22, df = 2; mid-nestling, t =-2.042, df = 2; late nestling = 0.81, df = 1; allP > 0.05; Table 8); i.e., adults did not adjustfor the greater food demands of four chicks,or were unable to do so. Nevertheless, bothof the closely watched nests with four chicksfledged all young. Three nests, including twowith four nestlings, lost one chick during thenestling period, perhaps related to food stress(Table 5). Thus, mean feedings per chick atfour-chick nests was somewhat lower (P >0.05) than at three-chick nests. Because thefeeding rates showed no significant difference

TABLE 7. Time of food deliveries to nestlings at five White-necked Crow nests at Los Haitises and Peder-nales, Dominican Republic, 1976, 2000, and 2001.

Observation periods (No. observation periods: total hours) Number of

Mann-Whitney test

Feeding trips Hours Feedings/h U PEarly (06:00-09:59 h; N = 8, ∑ = 26.9 h)Early vs Mid-day deliveriesMid-day (10:00-14:59 h; N = 8, ∑ = 37.7 h)Mid-day vs Late deliveriesLate (15:00-18:59 h; N = 5, ∑ = 15.6 h)Early vs Late deliveries

160

107

120

26.9

37.7

15.6

5.6 ± 1.3

3.4 ± 0.8

7.7 ± 1.11

96.5

36.0

41.5

0.0031

0.0040

0.0396

134


in three- and four-chick nests, I combined allnests to compare feeding rates among nestlingperiods (Table 8). Feeding rates at nests withearly nestlings (mean = 6.3 deliveries per h)were significantly higher than those at mid-nestling (4.4 per h; t = 2.62, df = 7, P = 0.035)and late nestling (4.6 per h; t = -3.27, df = 7, P= 0.014) stages. Feeding rates at mid and latenestling periods showed no difference (t =-0.09, df = 6, P = 0.928). Butler et al. (1984)noted that the feeding rates of nestling North-western Crows peaked in the second week,then declined to a low in the last week of nest-ling life.

Estimated sizes (animal matter) and quan-tities (plant) of items delivered by White-necked Crows were smaller during the mid-nestling period (mean = 27.5 + 0.61 g/h) thanduring the early nesting period (mean = 33.1+ 1.02 g/h; F0.05(1),1,4= 14.81, P = 0.018). Bio-

mass delivered to nests increased in the latenestling period (mean = 35.3 + 0.28 g/h; mid-vs late-nestling periods: F0.05(1),1,4= 104.0, P =0.0005; early- vs late-nestling periods:F0.05(1),1,4= 5.04, P = 0.088). Both adults fedchicks nearly equally, with one individualdelivering slightly more food than the otherparent; individual “A”: mean = 1.5 deliveries/h, individual “B”: 2.2/h (Z = 1.60, P = 0.105,N = 102; Wilcoxon paired-sample test). Butleret al. (1984) reported male NorthwesternCrows fed chicks more during the first week(when the adult female was most attentive atthe nest), but that females did most feedingthereafter.

When an attending crow detected mein its nest area, it called loudly with caw’s,oriented toward me, and performed anAlarm Display. The calling attracted theother adult, which joined in the calling.

TABLE 8. Feeding rates at White-necked Crow nest with three and four chicks during three periods ofobservation, Los Haitises (N = 3 chicks each) and Pedernales (N = 4 chicks each), Dominican Republic,1976, 2000, and 2001.

Stagesa Number of

Hours of observation

Food deliveries

Mean deliveries per

h

Mean feedings per

chicks

Mean feedings per chick per h

Three-chick nests (N = 3)Early nestlingMid-nestlingLate-nestling

TotalsFour-chick nests (N = 2)

Early nestlingMid-nestlingLate-nestling

TotalsAll nests (N = 5)

Early nestlingMid-nestlingLate-nestling

Totals

19.026.017.562.5

12.917.013.343.2

31.943.030.8105.7

1119780288

899464247

200191144535

5.83.74.6

6.95.54.8

6.34.44.6

37.032.226.7

22.323.516.0

58.856.242.4

1.91.21.5

1.71.41.2

1.91.31.4

aEarly nestling stage = days 0–13, mid-nestling stage = days 14–28, late nestling stage = days 29–44.

135

WILEY

When I was able to sneak into the nest areaso that I was quite close to the nest beforethe adult detected me, the attending adultassumed a low-profile “hiding” posture onthe nest until I was not looking in thatdirection or had passed the nest tree. Thenthe adult silently left the nest, circled aroundand returned to the area, loudly calling withcaw’s. Frequently, both adults would returnfrom the circling flight, then mob me. Thecrows displayed the same “hiding” andsneaking off behavior when Turkey Vulturesand Red-tailed Hawks passed over theirnests.

Adult crows frequently cleaned the nests.Adults ate or carried off small food scrapsand excreta of the chicks. They excavated inthe nest bowl; i.e., grabbed bowl twigs in theirbills and vigorously shook the material in arapid back and forth movement, presumablyto “sift” food, feces, and other debris out ofthe chicks’ bowl (Kilham 1984). Adults car-ried off large uneaten pieces of food, some-times to cache them nearby, but usually morethan 15 m and out of my sight. Nest sanita-tion activity by adults continued until the lastchick fledged.

ECTOPARASITES

Warble flies [Philornis (Neomusca) pici] are com-mon ectoparasites of birds at Los Haitises(Wiley & Wiley 1981, Snyder et al. 1987). Iinspected six White-necked Crow chicks (2nests) closely for ectoparasites. Three of these(from one nest) had minor infestations ofwarble fly larvae, distributed as follows: Chick# 1: three larvae on head, one on right thigh;Chick # 2: one larva on head; Chick # 3: twolarvae on breast, one on abdomen. All chickssurvived to fledging. One woodsman inPuerto Rico, Garciano Torres (age 83 yearswhen interviewed in 1976), remembered see-ing warble fly larvae on White-necked Crownestlings.

NATURAL PREDATION

In Los Haitises, adult White-necked Crowsapparently have few natural enemies otherthan man, and I observed few attempts atpredation of adult crows. Red-tailed Hawksmade what I considered the only “serious”attempts to take crows, although I observedno captures. Ridgway’s Hawks sometimeschased crows, apparently to supplant themfrom their nest area. I found no White-necked Crow remains at 18 Red-tailed Hawkand 14 Ridgway’s Hawk nests in my studyareas. Other potential nest predators includeblack rats (Rattus rattus), boas (Epicrates spp.),and arboreal lizards (especially Anolis ricordii).I did not find evidence of depredation atcrow nests, and observed a low incidence ofpredation on nests of other large bird speciesin the areas (Wiley & Wiley 1981, Snyder et al.1987).

CAUSES OF DECLINE OF WHITE-NECKED CROW POPULATIONS

As with most recent declines or extirpationsof avian populations in the West Indies, thedecline of White-necked Crow populationshas been the result of many factors, most ofwhich are related to man’s activities.

The most important of these factors hasbeen habitat destruction. The history of thecrow’s decline and extinction in Puerto Ricois particularly instructive in demonstrating theimportance of habitat change. In Puerto Rico,the crow’s decline in numbers and range isclosely related to the history of that island’sloss of old age forests (see Wadsworth 1949and Snyder et al. 1987 for history). The crow’slast refuge in Puerto Rico was apparently inthe mostly uncut forest in the Sierra deLuquillo, which was also the last sanctuary ofthe Puerto Rican Parrot (Amazona vittata)(Snyder et al. 1987). But, even though theSierra de Luquillo forest and its wildlife were

136


given legal protection, the forest wasdegraded through several activities, includingtimber stand improvement and charcoal har-vesting (Snyder et al. 1987), and the White-necked Crow continued to decline and even-tually disappeared.

Degradation and loss of habitat were notthe only factors involved in the crow’s extirpa-tion from Puerto Rico. Although Sallé (1857)and Wetmore (1916) believed the White-necked Crow required extensive tracts of nat-ural forest, my observations of sizable popula-tions of crows surviving in quite degradedhabitat in the Dominican Republic suggestthat pristine tracts of forest are not essentialfor the species’ survival (see below).

Hurricanes may have been direct and sec-ondary factors in the disappearance of theWhite-necked Crow from Puerto Rico, as thecrow became rarer there after Hurricane SanFelipe (1928; Danforth 1936, Rolle 1961). Asthe once extensive old-growth forest habitatwas fragmented for agriculture, crows werenot only exposed to greater “edge,” with thetemptation of crop depredation and increasedsusceptibility to shooting, but the crow’s largecontiguous populations were segregated intosmaller units separated from one another byunsuitable habitat. These fragmented popula-tions were more vulnerable to the randomtropical storms that savage the Caribbeanregion. When habitat was widespread andcrow populations were extensive in numberand distribution, hurricanes had only localeffects. Populations affected by the stormswere quickly replaced by surrounding reser-voirs of birds. Birds in storm-ravaged areascould easily move into nearby, less affectedareas for food and shelter (Wiley & Wunderle1993). But, when wildlife populations aresmall and habitat is reduced to small “islands,”surrounded by agriculture, a direct hit by ahurricane (such as occurred in 1928, whenHurricane San Felipe hit the limestone karstarea of western Puerto Rico) has a severe neg-

ative effect on bird populations. LeonardoBonnano Marques (90 years old in 1976)noted that crows became scarce in the Sierrade Luquillo after Hurricane San Ciprian(1932), whereas Gilberto Torres (83 years oldin 1976) recalled that crows disappeared fromareas after Hurricane San Ciriaco (1899).

Shooting has undoubtedly contributed tothe crow’s decline. Most of the older woods-men interviewed in the Sierra de Luquillo andRío Abajo areas of Puerto Rico reported thatcrows were shot in the past. One such person,Bernardo Vaquier (58 years old when inter-viewed in 1976), believed the crow disap-peared from around his home in Caritebecause of excessive shooting. Because theyare noisy and aggressive around the nest andin feeding flocks, White-necked Crows areeasy to find and shoot. Esquemeling (1684–1685) wrote, “These clamorous birds do nosooner hear the report of a fowling piece ormusket but they gather from all sides intowhole flocks, and fill the air and woods withtheir unpleasant notes.” Such noisy congrega-tions must have made the crow easy prey for aman with a gun.

The White-necked Crow has been consid-ered a game species whose flesh was valued(Abbad y Lasierra 1788, Wetmore 1916, Ver-rill 1926, Wetmore & Swales 1931, Raffaele1983). Verrill (1926) reported that during theperiods when they congregated for feeding,thousands of crows were shot and sold inmarkets. The appeal of the species as foodvaries locally. I found hunters in some areas ofthe Dominican Republic who consideredcrows undesirable as a game bird. Conversely,most of the interviewed older woodsmen whowere familiar with the crow in Puerto Ricoreported that it was a favorite local food. Gar-ciano Juarbez Torrez (96 years old when inter-viewed in 1976) remembered that crows weretaken as nestlings for food. Despite laws toprevent it, illegal hunting continued in theSierra de Luquillo through the mid-1970s,

137

WILEY

when stepped-up enforcement substantiallyreduced the activity. That enforcement was,regrettably, too late for the White-neckedCrow.

White-necked Crows eat corn, beans, andother crops (Gundlach 1874, Dod 1978; pers.observ.), and many are shot to protect crops(interviews of older residents of Puerto Ricoand the Dominican Republic). Württemberg(1835) noted that White-necked Crows for-merly came fearlessly about houses in flocksof hundreds of birds, perhaps to feed oncrops.

Disease is a possible factor in the extirpa-tion of the White-necked Crow in PuertoRico and has been suggested as a potentialreason for the decline of the Puerto RicanParrot (Snyder et al. 1987). Disease has provento be an important factor in the decline of theHawaiian Crow (Corvus hawaiiensis) and is nowperhaps the most critical problem in prevent-ing that species’ recovery (Giffin et al. 1987,Jenkins et al. 1989).

Predation by Pearly-eyed Thrashers (Mar-garops fuscatus) and introduced rats (Rattus nor-vegicus and R. rattus) likely contributed to thecrow’s decline in Puerto Rico. Rats are com-mon throughout habitats used by crows. Theyare known to eat bird eggs and chicks, butnormally will not enter a large bird’s nestwhen an adult is present (Snyder et al. 1987).Also, they are normally active only during thenight, when adult White-necked Crows areconsistently at the nest. Nevertheless, ratsmay have occasional opportunities to invade acrow nest when the adult has been scared offfor the night or a marauding rat may take anegg or chick during the day.

The Pearly-eyed Thrasher is a recentinvader of Puerto Rican forests (Snyder et al.1987) and, apparently, is only beginning tocolonize mainland Hispaniola (Wiley &Ottenwalder 1990, Keith et al. 2003). Thrash-ers are aggressive predators of birds’ eggs andchicks but, like rats, will not normally attack

an attended nest. The recent arrival of thethrasher into an environment with no suchnest predator perhaps exposed the naïvecrow, which likely had no effective defense tocounter the threat. Indeed, I observed White-necked Crows leaving eggs and young chicksunguarded (3.6% and 11.1%, respectively, ofdaytime observation periods) for sufficienttime to allow a thrasher to destroy a nestunchallenged by an adult crow. Predation bythrashers may have been the “coup-de-grâce”for the crow in the Sierra de Luquillo.

The hypothesis that thrashers played acritical role in the extirpation of the White-necked Crow from Puerto Rico is supportedby events in my Los Haitises study area overthe period 1974–1996. When I began field-work in Los Haitises in 1974, the area waslargely continuous forest, with small inroadsof local cultivation. White-necked Crowswere in good numbers and evenly distributedthrough the forest. By 1996, the forest hadbeen largely cleared, with only small (0.05 ha)fragments remaining, separated by largeareas of active and abandoned cultivation.Nevertheless, crow populations remainedunchanged in numbers and general distribu-tion. Using the same methods as in 1976 sur-veys, I found an average of 0.020 crowsdetected per minute in 1996 (total = 1600 minof surveys), whereas I encountered 0.029crows per minute in 1976 (total = 5940 min).Crows were breeding (incubating) in March–April 1996 and were well distributed in thedegraded habitat. All other pressures appar-ently remained the same: shooting was, as inthe 1970s, at a low level. If anything, I wouldexpect persecution from humans protectingtheir crops to have increased with the moreactive agriculture in the area in the 1990s. Ratpopulations were still quite high, as they werein the 1970s. The only major element that dif-fered between Puerto Rico and Los Haitiseswas the absence of the Pearly-eyed Thrasherin the latter site. Crow egg and chick depreda-

138


tion by the thrasher, combined with near-complete habitat destruction and shooting,seem to be the most likely causes of theWhite-necked Crow’s disappearance fromPuerto Rico.

REINTRODUCTION TO PUERTO RICO

Little has been done (of an effective nature)toward conservation of the White-neckedCrow. A petition for listing the crow as a spe-cies of special concern was reviewed by the U.S. government in 1986–1987 (Federal Register1987). The review concluded that more infor-mation was needed to determine the status ofthe crow in Hispaniola. Furthermore, as a for-eign species the priority for seeking the neces-sary data was deemed somewhat lower thanthat accorded domestic species, while costs toobtain the data were expected to be higher.The conclusion was that “…the best scientificand commercial information available supporta finding that the action (listing as endan-gered) requested is warranted, but precludedby work on other species judged to be ingreater need of protection.”

I suggest that a program to re-establishthe crow should be undertaken in PuertoRico. I feel it would be prudent to harvestWhite-necked Crows from Hispaniola andattempt releases in Puerto Rico for severalreasons. First, the crow is declining in num-bers and range with the accelerating habitatdestruction in Hispaniola, and may becomeextinct there, too, without additional conser-vation measures. With the current desperatestate of the country’s economy and limitedhabitat for crows, there is little reason foroptimism for the crow in Haiti. The Domini-can Republic is also experiencing a severelypoor economic period, wherein concern forthe country’s natural resources has becomesecondary to the primary needs of humans.Nevertheless, the Dominican Republic is per-haps 100 years “behind” Puerto Rico, where

the cutting of forests peaked in the first quar-ter of the 20th century (Wadsworth 1949,Snyder et al. 1987). Although considerablearea has been set aside in natural reserves, andseveral of these have been quite effective inconserving natural resources, human exploita-tion has continued unchecked at others,including Parque Nacional Los Haitises.Although the Dominican government initiallytook a strong position within the Park, relo-cating people out of Los Haitises, providingfood subsidies to people to dissuade furthercutting of vegetation, and levying fines and jailpenalties for persons convicted of farming orcutting within the Park, forest clearing hascontinued within the protected area. Contin-ued exploitation of important crow habitat,along with other negative factors (e.g., spreadof the Pearly-eyed Thrasher), could result inthe loss of the White-necked Crow in theDominican Republic.

A second reason for re-introducing crowsin Puerto Rico is that an opportunity stillexists to obtain crows from Hispaniolan pop-ulations that would not be affected by such aharvest. A suitable source of White-neckedCrows still exists in parts of the DominicanRepublic. Although Cory (1886) suggestedPuerto Rican specimens differed somewhatfrom Hispaniolan birds, and Ridgway(1904:279) recognized racial differencesbetween the “Haitian” [= Hispaniola] crow(C. l. erythrophthalmus) and Puerto Rican popu-lations (C. l. leucognaphalus) of the White-necked Crow, other workers concluded thatthe Puerto Rican and Hispaniolan popula-tions do not differ enough to warrant treat-ment as subspecies (Meinertzhagen 1926,Wetmore 1927, Wetmore & Swales 1931,Johnston 1961). Thus, at least morphologi-cally, crows introduced from Hispaniolawould be similar to those formerly inhabitingPuerto Rico.

Third, many of the problems responsiblefor the crow’s loss from Puerto Rico are now

139

WILEY

controllable: (1) habitat destruction hasebbed. More forest and woodland habitatexists now (40% of the island in forests, albeitsecond-growth; Schmidt 1982) than in 1912(< 2%). (2) The large area of second-growthforest in Puerto Rico would now serve toabsorb effects of a severe storm. A direct hitby a storm would only be serious during theinitial stages of reintroduction, when numbersare low and the populations are concentratedabout the release areas. When each of severalintroduced populations grows in number andrange, storms would become what they oncewere – threats to only local communities andnot to the species. (3) Agriculture is not asimportant now as formerly; fewer farms areactive and there would be fewer conflicts overcrop depredation. (4) Hunting is much bettercontrolled.

Pearly-eyed Thrashers (and rats to a lesserdegree) would still be a threat to crows rein-troduced to Puerto Rico. Areas with relativelylow densities of thrashers exist (e.g., RíoAbajo; Snyder et al. 1987), however, and rein-troductions could be first attempted there.Río Abajo is a wet limestone area, similar tothe Haitises area used by White-neckedCrows in Hispaniola, and was formerly inhab-ited by the crow. Reintroduced crows couldshare resources of conservation projectsalready planned for the Commonwealth ofPuerto Rico Río Abajo Forest; i.e., releases ofthe Puerto Rican Plain Pigeon (Patagioenasinornata wetmorei) and Puerto Rican Parrot(Wadsworth et al. 1982, Wiley et al. 1982). Thecrow reintroduction could be part of a con-servation effort to “reconstruct” a part ofPuerto Rico’s recent ecosystems (Wiley 1985).Eventually, other extirpated species, such asthe Limpkin (Aramus guarauna) and perhapsthe ground iguana [Cyclura pinguis (= C. portori-censis)], still extant in other countries, could bere-established in Puerto Rico. Such a refugewould establish additional disjunct popula-tions of animals whose populations may be

declining toward extinction, or as supplemen-tary populations to help secure species nowconfined to small areas (e.g., C. pinguis onAnegada). Certainly, under current conditionsand prognoses, the White-necked Crow canbe expected to decline further in Hispaniola.Another population established in PuertoRico could serve as insurance against the spe-cies’ extinction if the Hispaniolan populationdisappears.

Being as adaptable as apparently thecrow has been during changing environmentsin the Dominican Republic, and with itsgeneralistic food habits, I suspect that rein-troduction problems would be few. Oneconcern, however, might be for otherendangered bird species planned for intro-duced into the Río Abajo Forest, if that siteis chosen for crow releases. I suspect the mostserious problem among these birds wouldcome from nest depredations, although allforms once coexisted in the karst zoneobviously with some kind of natural balance.Crows are known to be predators of pigeoneggs and squabs and may thereby pose athreat to the recovery efforts for the PlainPigeon. Similarly, parrot nests are oftendepredated by Cuban Crows (pers. observ.),and reintroduced populations of the White-necked Crow to the karst zone of PuertoRico may thereby have negative effectson the re-establishment of Puerto RicanParrots there. Competition for food and habi-tat should be a minor issue in a sympatricrelease.

Although other species of endangeredcrows (e.g., Hawaiian Crow) have been suc-cessfully managed in captive breeding pro-grams (Giffin 1989, Whitmore & Marzluff1998), it would seem more prudent for therelease in Puerto Rico to consist of birdscaught wild from Hispaniola as free-flyingbirds. Juvenile White-necked Crows associatefor considerable time with their parents andlarge flocks of crows, likely gaining substantial

140


survival skills. Further, they may be similar tomany other crow species in not breeding untilafter their second year. Thus, if young birdsare used in translocations, it would be advis-able to release groups of birds containingolder as well as recently fledged individuals toimprove the chance of success of introductionefforts. If naïve young crows are used, pre-release aversion training would be advisable toenhance their predator recognition and avoid-ance skills (Wiley et al. 1992).

A potentially serious threat to efforts tore-establish White-necked Crow populationsin Puerto Rico and, indeed, to the conserva-tion of the species range-wide, is disease. WestNile virus has been reported from all ofthe Greater Antilles (Komar et al. 2003b,Dupuis et al. 2005), and virus-neutralizingantibodies have been found in resident birdsin Cuba, Jamaica, Dominican Republic,and Puerto Rico (Dupuis et al. 2003, Komar etal. 2003b, Dupuis et al. 2005). The virus islikely transmitted by infected migratory birdsfrom North America (Dupuis et al. 2005).American Crows are highly susceptible to theWest Nile virus (Caffrey et al. 2003, Komar etal. 2003a), and some crow populations haveundergone an unprecedented and sustaineddecline since the virus arrived (Caffrey &Peterson 2003, Caffrey et al. 2005). It is likelythat West Indian crows will show similar sus-ceptibility to the arbovirus, and may alsodecline as a result of the disease. In 2002,Komar et al. (2003b) tested resident andmigratory birds for flavivirus-neutralizingantibodies at Los Haitises and Sierra de Baho-ruco, two strongholds of the White-neckedCrow in the Dominican Repulic. Their resultssuggested that transmission of West Nilevirus among bird populations at Los Haitiseswas widespread. The presence of the virus inHispaniola poses a grave threat to the crow,particularly in combination with colonizationof the island by the Pearly-eyed Thrasher(Keith et al. 2003).

ACKNOWLEDGMENTS

I was ably assisted in the field by JulioCardona, Joan Duffield, Elizabeth Litovich,John Taapken, and Beth Wiley. Tudy andDon Dod, José A. Ottenwalder, and SixtoInchaustugui generously provided logisticaland technical support for the study. I thankthe administration and staff of the MuseoNacional de Historia Natural (Santo Dom-ingo) for logistical support. The research wasfunded by the Commonwealth of Puerto RicoDepartamento de Recursos Naturales (1974),U. S. Department of Agriculture – ForestService (1975–1977), and U. S. Departmentof the Interior – Fish and Wildlife Service(1978–1989), National Biological Survey(1996), and U. S. Geological Survey(2000–2004). Additional support camefrom National Science Foundation, WildlifePreservation Trust International, WorldParrot Fund, and the International CraneFoundation. I thank my supervisors fortheir support during the fieldwork: Drs. Edu-ardo Cardona and Eduardo Angel, PuertoRico Departmento de Recursos Naturales,Dr. Frank H. Wadsworth, Institute of TropicalForestry, Drs. Ray C. Erickson and H. Ran-dolph Perry, Patuxent Wildlife Research Cen-ter, and Drs. Reed Goforth, Michael Tome,and James Fleming, Cooperative ResearchUnits. Carlos A. Delannoy, Dwight Smith,and Julio Cardona facilitated interviewsin Puerto Rico, for which I thank them.Matilda Mota G. (Parques Nacionales,República Dominicana) provided permits towork in the national parks of the Domini-can Republic. Dr. Mary LeCroy providedaccess to the field notes of Rollo Beckat the American Museum of NaturalHistory. I thank Gina Mori and AlmaRamírez for their help with the resumen. Themanuscript was improved through the sugges-tions of A. B. Clark and two anonymousreviewers.

141

WILEY

REFERENCES

Abbad y Lasierra, I. 1788. Historia geográfica, civily politica de la isla de San Juan Bautista dePuerto Rico. Madrid. (1979 edition, EditorialUniversitaria, Río Piedras, Puerto Rico).

A. O. U. 1998. Check-list of North American birds.7th ed. American Ornithologists’ Union, Wash-ington, DC.

Barbour, T. 1943. Cuban ornithology. NuttallOrnithological Club, Cambridge, Massachus-setts.

Baumel, J. J. 1953. Wing claws in the White-neckedCrow (Corvus leucognaphalus). Auk 70: 373.

Beck, R. H. 1916. Dominican Republic. Unpub-lished field notes deposited at the AmericanMuseum of Natural History, New York, NewYork.

Biaggi, V. 1983. Las aves de Puerto Rico. 3rd ed.Editorial Universitaria, Univ. de Puerto Rico,San Juan, Puerto Rico.

Blake, S. F. 1957. The function of the concealedthroat-patch in the White-necked Raven. Auk74: 95–96.

Bond, J. 1928. The distribution and habits of thebirds of the Republic of Haiti. Proc. Acad. Nat.Sci. Phila. 80: 483–521.

Bond, J. 1947. Field guide to birds of the WestIndies. Macmillan Co., New York, New York.

Bond, J. 1973. Eighteenth supplement to thecheck-list of birds of the West Indies (1956).Academy of Natural Sciences, Philadelphia,Pennsylvania.

Bond, J. 1977. Twenty-first supplement to thecheck-list of birds of the West Indies (1956).Academy of Natural Sciences, Philadelphia,Pennsylvania.

Brodkorb, P. 1959. Pleistocene birds from NewProvidence Island, Bahamas. Bull. Fla. StateMus. Biol. Sci. Ser. 4: 349–371.

Butler, R. W., N. A. M. Verbeek, & H. Richardson.1984. The breeding biology of the Northwest-ern Crow. Wilson Bull. 96: 408–418.

Byrkjedal, I. 1987. Antipredator behavior andbreeding success in Greater Golden-Plover andEurasian Dotterel. Condor 89: 40–47.

Caffrey, C. 2000. Correlates of reproductive suc-cess in cooperatively breeding western Ameri-can Crows: if helpers help, it's not by much.

Condor 102: 333–341.Caffrey, C., & C. C. Peterson. 2003. West Nile virus

may not be a conservation issue in northeast-ern United States. Am. Birds 103rd ChristmasBird Count: 14–21.

Caffrey, C., S. C. R. Smith, & T. J. Weston. 2005.West Nile virus devastates an American Crowpopulation. Condor 107: 128–132.

Caffrey, C., T. J. Weston, & S. C. R. Smith. 2003.High mortality among marked crows subse-quent to the arrival of West Nile virus. Wildl.Soc. Bull. 31: 870–872.

Chamberlain, D. R., & G. W. Cornwell. 1971.Selected vocalizations of the Common Crow.Auk 88: 613–634.

Charles, J. K. 1972. Territorial behavior and thelimitation of population in the crow, Corvus cor-one and Corvus cornix. Ph.D. thesis, AberdeenUniv., Aberdeen, Scotland.

Cherrie, G. K. 1897. Contributions to the ornithol-ogy of San Domingo. Field ColumbianMuseum, Publication 10, Ornithological Series,Volume 1, No. 1, Chicago, Illinois.

Clark, C. C., L. Clark, & L. Clark. 1990. Antingbehavior by Common Grackles and EuropeanStarlings. Wilson Bull. 102: 167–169.

Connor. R. N. 1985. Vocalizations of CommonRavens in Virginia. Condor 87: 379–388.

Coombs, C. J. F. 1960. Observations on the RookCorvus frugilegus in southwest Cornwall. Ibis 102:394–419.

Cory, C. B. 1886. The birds of the West Indies,including the Bahama Islands, the Greater andLesser Antilles, excepting the islands of Tobagoand Trinidad. Auk 3: 187–245.

Cruz, A. 1972. Food and feeding behavior of theJamaican Crow, Corvus jamaicensis. Auk 89: 445–446.

Danforth, S. T. 1929. Notes on the birds of His-paniola. Auk 46: 358–375.

Danforth, S. T. 1936. Pájaros de Puerto Rico. RandMcNally & Co., New York, New York.

Dod, A. S. 1978. Las aves de la República Domini-cana. Museo Nacional Historia Natural, SantoDomingo, República Dominicana.

Dod, A. S. 1992. Endangered & endemic birds ofthe Dominican Republic. Cypress House Press,Fort Bragg, California.

Dorst, J. 1947. Révision systématique du genre Cor-

142


vus. Oiseau 17: 44–87.Dupuis, A. P., II, P. P. Marra, & L. D. Kramer. 2003.

Serological evidence of West Nile virus trans-mission, Jamaica, West Indies. Emerging Infec-tious Diseases 9: 860–863.

Dupuis, A. P., II, P. P. Mara, R. Teitsma, M. J. Jones,K. Louie, & L. D. Kramer. 2005. Serologic evi-dence for West Nile virus transmission inPuerto Rico and Cuba. Am. J. Trop. Med. Hyg.73: 474–476.

Emlen, J. T., Jr. 1942. Notes on a nesting colony ofwestern crows. Bird-Banding 13: 143–154.

Engel, K. A., & L. S. Young. 1989. Spatial and tem-poral patterns in the diet of Common Ravensin southwestern Idaho. Condor 91: 372–378.

Engel, K. A., & L. S. Young. 1992. Movements andhabitat use by Common Ravens from roostsites in southwestern Idaho. J. Wildl. Manage.56: 596–602.

Engel, K. A., L. S. Young, K. Steenhof, J. A. Roppe,& M. N. Kochert. 1992. Communal roosting ofCommon Ravens in southwestern Idaho. Wil-son Bull. 104: 105–121.

Esquemeling, J. 1684–1685. The buccaneers ofAmerica. George Routlege & Sons, Ltd., Lon-don, UK.

Evans, R. M. 1970. Oldsquaws nesting in associa-tion with Arctic Terns at Churchill, Manitoba.Wilson Bull. 82: 383–390.

Federal Register. 1987. [White-necked Crow peti-tion.] Federal Register 52 FR 24485, July 1,1987. Washington, DC.

Fisher-Meerow, L. L. 1983. Floristics, ecology, phy-togeography, and history of botanical explora-tion of the Sierra de Bahoruco, DominicanRepublic. M. Sc. thesis, Univ. Florida, Gaines-ville, Florida.

Fisher-Meerow, L. L., & W. S. Judd. 1989. A floris-tic study of five sites along an elevationaltransect in the Sierra de Baoruco, Prov. Peder-nales, Dominican Republic. Moscosoa 5: 159–185.

Forbush, E. H. 1927. Birds of Massachusetts andother New England states. Vol. 2. Massachu-setts Dept. Agric., Boston, Massachusetts.

Garrido, O. H., & A. Kirkconnell. 2000. Field guideto the birds of Cuba. Cornell Univ. Press, Ith-aca, New York.

Garrido. O. H., G. B. Reynard, & A. Kirkconnell.

1997. Is the Palm Crow, Corvus palmarum (Aves:Corvidae), a monotypic species? Ornitol.Neotrop. 8: 15–21.

Gaston, A. J., & R. D. Elliot. 1996. Predation byravens Corvus corax on Brunnich's GuillemotUria lomvia eggs and chicks and its possibleimpact on breeding site selection. Ibis 138:742–748.

Giffin, J. G. 1989. Captive propagation of birds. Pp.103–106 in Stone, C. P., & D. B. Stone (eds.).Conservation biology in Hawaii. Univiversity ofHawaii Cooperative National Park ResourcesStudies Unit, Honolulu, Hawaii.

Giffin, J. G., J. M. Scott, & S. Mountainspring.1987. Habitat selection and management of theHawaiian Crow. J. Wildl. Manage. 51: 485–494.

Golding, P. 1983. Haitian birds. Gosse Bird ClubBroadsh. 40: 15.

Good, E. E. 1952. The life history of the AmericanCrow – Corvus brachyrhynchos Brehm. Ph.D. diss.,Ohio St. Univ., Columbus, Ohio.

Goodwin, D. 1976 Crows of the world. CornellUniv. Press, Ithaca, New York.

Gosse, P. H. 1847. The birds of Jamaica. John vanVoorst, London, UK.

Gotmark, F., R. Neergaard, & M. Ahlund. 1990.Predation of artificial and real Arctic Loonnests in Sweden. J. Wildl. Manage. 54: 429–432.

Greenway, J. C., Jr. 1958. Extinct and vanishingbirds of the world. American Committee forInternational Wild Life Protection, Spec. Publ.13, New York, New York.

Gundlach, J. 1874. Beiträge zur Ornithologie delInsel Portorico. J. Ornithol. 22: 304–315.

Gundlach, J. 1878. Neue Beiträge zur Ornithologieder Insel Porto Rico. J. Ornithol. 26: 157–194.

Gwinner, E. 1964. Untersuchungen über das Aus-drucks– und Sozialverhalten des Kolkraben(Corvus corax corax L.). Z. Tierpsychol. 21: 657–748.

Hansen, H., C. A. Smedshaug, & G. A. Sonerud.2000. Preroosting behaviour of Hooded Crows(Corvus corone cornix). Can. J. Zool. 78: 1813–1821.

Harlow, R. F., R. G. Hooper, D. R. Chamberlain, &H. S. Crawford. 1975. Some winter and nestingseason foods of the Common Raven in Vir-ginia. Auk 92: 298–306.

Haydock, J., & J. D. Ligon. 1986. Brood reduction

143

WILEY

in the Chihuahuan Raven: an experimentalstudy. Ecology 67: 1194–1205.

Heinrich, B. 1999. Planning to facilitate caching:possible suet cutting by a Common Raven. Wil-son Bull. 111: 276–278.

Heinrich, B., D. Kaye, T. Knight, & K. Schaum-burg. 1994. Dispersal and association amongCommon Ravens. Condor 96: 545–551.

Holyoak, D. T. 1967. Breeding biology of the Cor-vidae. Bird Study 14: 153–168.

Holyoak, D. T. 1983. Notes on the Palm Crow Cor-vus palmarum in Haiti. Bull. Br. Ornithol. Club103: 81–82.

Ignatiuk, J. B., & R. G. Clark. 1991. Breeding biol-ogy of American Crows in Saskatchewan park-land habitat. Can. J. Zool. 69: 168–175.

Jacobsen, O. W., & M. Ugelvik. 1992. Anti-preda-tor behavior of breeding Eurasian Wigeon. J.Field Ornithol. 63: 324–330.

James, P. C., & N. A. M. Verbeek. 1985. Clam stor-age in a Northwestern Crow (Corvus caurinus):dispersion and sequencing. Can. J. Zool. 63:857–860.

Jenkins, D. C., S. A. Temple, C. van Riper, & W. R.Hansen. 1989. Disease-related aspects ofconserving the endangered Hawaiian Crow.Pp. 77–87 in Cooper, J. E. (ed.). Disease andthreatened birds. ICBP Tech. Publ. No. 10,International Council for Bird Preservation,Cambridge, UK.

Johnston, D. W. 1961. The biosystematics ofAmerican crows. Univ. Washington Press, Seat-tle, Washington.

Johnston, R. F. 1958. Function of cryptic white inthe White-necked Raven. Auk 75: 350–351.

Jollie, M. 1978. Phylogeny of the species of Corvus.Biologist 60: 73–108.

Keith, A. R., J. W. Wiley, S. C. Latta, & J. A. Otten-walder. 2003. The birds of Hispaniola. Haitiand the Dominican Republic. BOU ChecklistNo. 21, British Ornithologists’ Union, Tring,UK.

Kilham, L. 1984. Cooperative breeding of Ameri-can Crows. J. Field Ornithol. 55: 349–356.

Kilham, L. 1985a. Territorial behavior of AmericanCrows. Wilson Bull. 97: 389–390.

Kilham, L. 1985b. Behavior of American Crows inthe early part of the breeding cycle. Fla. FieldNat. 13: 25–31.

Kilham, L. 1989. The American Crow and theCommon Raven. W. L. Moody, Jr. Natural His-tory Series, No. 10. Texas A&M Univ. Press,College Station, Texas.

Komar, N., S. Langevin, S. Hinten, N. Nemeth, E.Edwards, D. Hettler, B. Davis, R. Bowen, & M.Bunning. 2003a. Experimental infection ofNorth American birds with the New York 1999strain of West Nile virus. Emerg. Infect. Dis. 9:311–323.

Komar, O., M. B. Robbins, K. Klenk, B. J. Blitvich,N. L. Marlenee, K. L. Burkhalter, D. J. Gubler,G. Gonzálvez, C. J. Peña, A. T. Peterson, & N.Komar. 2003b. West Nile virus transmission inresident birds, Dominican Republic. Emerg.Infect. Dis. 9: 1299–1302.

Lack, D. 1976. Island biology. Illustrated by theland birds of Jamaica. Univ. California Press,Berkeley, California.

Lamm, D. W. 1958. A nesting study of the PiedCrow at Accra, Ghana. Ostrich 29: 59–70.

Little, E. L., Jr., & F. H. Wadsworth. 1964. Com-mon trees of Puerto Rico and the VirginIslands. Agriculture Handbook No. 249,United States Department of Agriculture –Forest Service, Washington, DC.

Little, E. L., Jr., R. O. Woodbury, & F. H. Wad-sworth. 1974. Trees of Puerto Rico and theVirgin Islands, second volume. AgricultureHandbook No. 449, United States Departmentof Agriculture – Forest Service, Washington,DC.

Littlefield, C. D. 1995. Demographics of a declin-ing flock of Greater Sandhill Cranes in Oregon.Wilson Bull. 107: 667–674.

Lockie, J. D. 1955. The breeding and feeding ofJackdaws and Rooks with notes on CarrionCrows and other Corvidae. Ibis 97: 341–369.

Lorenz, K. 1931. Beiträge zur Ethologie sozialerCorviden. J. Ornithol. 79: 511–519.

Maccarone, A. D. 1987. Sentinel behavior in Amer-ican Crows. Bird Behav. 7: 93–95.

Madge, S., & H. Burn. 1994. Crows and jays. Aguide to the crows, jays and magpies of theworld. Houghton Mifflin Co., New York, NewYork.

Mason, C. R. 1960. Log of the Caribbean....April1–12, 1958. Florida Nat. 33: 30–37.

Meinertzagen, R. 1926. Introduction to a review of

144


the genus Corvus. Nov. Zool. 33: 57–119.Monroe, B. L., Jr., & C. S. Sibley. 1993. A world

checklist of birds. Yale University Press, NewHaven, Connecticut.

Moore, J. E., & P. V. Switzer. 1998. Preroostingaggregations in the American Crow, Corvusbrachyrhynchos. Can. J. Zool. 76: 508–512.

Nogales, M., & E. C. Hernández. 1994. Interinsularvariations in the spring and summer diet of theRaven Corvus corax in the Canary Islands. Ibis136: 441–447.

Nogales, M., & E. C. Hernández. 1997. Diet ofCommon Ravens on El Hierro, Canary Islands.J. Field Ornithol. 68: 382–391.

Olson, S. L., & W. B. Hilgartner. 1982. Fossil andsubfossil birds from the Bahamas. Pp. 22–56 inOlson, S. L. (ed.). Fossil vertebrates from theBahamas. Smithsonian Institution Contribu-tions Paleobiology No. 48, Washington, DC.

Parmelee, D. F., & J. M. Parmelee. 1988. Ravensobserved killing roosting Kittiwakes. Condor90: 952.

Peters, J. 1917. Birds of the northern coast of theDominican Republic. Bull. Mus. Comp. Zool.61: 391–426.

Petit, C., M. Hossaert-McKey, P. Perret, J. Blondel,& M. M. Lambrechts. 2002. Blue Tits useselected plants and olfaction to maintain anaromatic environment for nestlings. EcologyLetters 5: 585–589.

Poncy, R. 1938. Observations concernant le Cor-beau Corneille. Ornithol. Beob. 35: 138–139.

Raffaele, H. A. 1983. A guide to the birds of PuertoRico and the Virgin Islands. Fondo EducativoInteramericano, San Juan, Puerto Rico.

Ridgway, R. 1904. The birds of North and MiddleAmerica. United States National Museum Bul-letin 50, part III. Washington, DC.

Rolle, F. J. 1961. Notes and records of little-knownspecies of birds from Puerto Rico. J. Agric.Univ. P. R. 45: 333–341.

Rowley, I. 1967. Sympatry in Australia ravens. Proc.Ecol. Soc. Aust. 2: 107–115.

Rowley, I. 1974. Display situations in two Austra-lian ravens. Emu 74: 47–52.

Saino, N., & F. De Bernardi. 1994. Geographicvariation in size and sexual dimorphism acrossa hybrid zone between Carrion Crows (Corvuscorone corone) and Hooded Crows (C. c. cornix).

Can. J. Zool. 72: 1543–1550.Sallé, M. A. 1857. Liste des oiseaux rapportés, et

observés dans la Republique Dominicaine(Ancienne partie espagnole de l’Ile St.Domingue ou d’Haiti) par M. C. Sallé, pendantson voyage de 1849 à 1851. Proc. Zool. Soc.London 1857: 230–237.

Schmidt, R. 1982. Forestry in Puerto Rico. Pp. 69–71 in Lugo, A. E., & S. Brown (eds.). Forestry inthe Caribbean. U. S. Man & Biosphere ReportNo. 7, Washington, DC.

Sharpe, R. B. 1877. Catalogue of the birds in theBritish Museum. Volume 3 (Cat. of the Passeri-formes or perching birds, in the Brit. Museum:Coliomorphae, containing the families Cor-vidae, Paradiseidae, Oriolidae, Dicruridae, andPrionopidae). Taylor & Francis, London, UK.

Skead, C. J. 1952. A study of the Black Crow Corvuscapensis. Ibis 94: 434–451.

Snyder, N. F. R., J. W. Wiley, & C. B. Kepler. 1987.The parrots of Luquillo: natural history andconservation of the Puerto Rican Parrot. West-ern Foundation of Vertebrate Zoology, LosAngeles, California.

Stiehl, R. B. 1985. Brood chronology of the Com-mon Raven. Wilson Bull. 97: 78–87.

Stiehl, R. B., & S. N. Trautwein. 1991. Variations indiets of nesting Common Ravens. Wilson Bull.103: 83–92.

Storer, R. W. 1966. Sexual dimorphism and foodhabits in three North American accipiters. Auk83: 423–436.

Turcek, F. J., & L. Kelso. 1968. Ecological aspectsof food transportation and storage in the Cor-vidae. Communs. Behav. Biol. 2: 127–297.

USDA, NRCS. 2004. The PLANTS Database, ver-sion 3.5 (http://plants.usda.gov). NationalPlants Data Center, Baton Rouge, Louisiana.

Vargas Mora, T. A., & W. J. Arendt. 1978. Estudiosobre la Paloma Coronita (Columba leucocephala)(Febrero–Septiembre, 1978). Unpubl. reportdated 15 September 1978, Museo Nacional deHistoria Natural, Santo Domingo, DominicanRepublic.

Verbeek, N. A. M. 1995. Body temperature andgrowth of nestling Northwestern Crows, Corvuscaurinus. Can. J. Zool. 73: 1019–1023.

Verbeek, N. A. M. 1997. Food cache recovery byNorthwestern Crows (Corvus caurinus). Can. J.

145

WILEY

Zool. 75: 1351–1356.Verbeek, N. A. M., & R. W. Butler. 1981. Co-opera-

tive breeding of the Northwestern Crow Corvuscaurinus in British Columbia. Ibis 123: 183–189.

Verrill, A. E., & A. H. Verrill. 1909. Notes on thebirds of San Domingo, with a list of the spe-cies, including a new hawk. Proc. Acad. Nat.Sci. Phila. 61: 352–366.

Verrill, A. H. 1926. Porto Rico, past and present,and San Domingo of to-day. Dodd, Mead &Co., New York, New York.

Wadsworth, F. H. 1949. The development of theforest land resources of the Luquillo Moun-tains, Puerto Rico. Ph.D. diss., Univ. Michigan,Ann Arbor, Michigan.

Wadsworth, F. H., N. F. R. Snyder, H. A. Raffaele,J. W. Wiley, & A. Rodriguez. 1982. Puerto RicanParrot recovery plan. U. S. Fish & Wildlife Ser-vice, Atlanta, Georgia.

Wetmore, A. 1916. Birds of Porto Rico. U. S. Dep.Agric. Bull. 326: 1–140.

Wetmore, A. 1918. Bones of birds collected byTheodoor de Booy from kitchen middendeposits in the islands of St. Thomas and St.Croix. Proc. U. S. Natl. Mus. 54: 513–522.

Wetmore, A. 1920. Five new species of birds fromcave deposits in Puerto Rico. Proc. Biol. Soc.Wash. 33: 77–78.

Wetmore, A. 1925. Another record for the genusCorvus in St. Croix. Auk 42: 446.

Wetmore, A. 1927. The birds of Porto Rico andthe Virgin Islands. Pp. 409–598 in ScientificSurvey of Porto Rico and the Virgin Islands.Volume 9, Parts 3 & 4. New York Academy ofScience, New York, New York.

Wetmore, A. 1937. Ancient records of birds fromthe island of St. Croix with observations onextinct and living birds of Puerto Rico. J. Agric.Univ. P. R. 21: 5–16.

Wetmore, A., & B. H. Swales. 1931. The birds ofHaiti and the Dominican Republic. U. S. Natl.Mus. Bull. 155: 1–483.

Whitmore, K. D., & J. M. Marzluff. 1998. Hand-rearing corvids for reintroduction: importanceof feeding regime, nestling growth, and domi-nance. J. Wildl. Manage. 62: 1460–1479.

Wiley, J. W. 1985. Bird conservation in the United

States Caribbean. Bird Conserv. 2: 107–159.Wiley, J. W., & J. A. Ottenwalder. 1990. Birds of

Islas Beata and Alto Velo, Dominican Republic.Stud. Neotrop. Fauna Environ. 25: 65–88.

Wiley, J. W., N. F. R. Snyder, R. Cotte, W. Parker, &A. Rodríguez. 1982. Puerto Rican Plain Pigeonrecovery plan. U. S. Fish & Wildlife Service,Atlanta, Georgia.

Wiley, J. W., N. F. R. Snyder, & R. S. Gnam. 1992.Reintroduction as a conservation strategy forparrots. Pp. 165–200 in Beissinger, S. R., & N.F. R. Snyder (eds.). New World parrots in crisis.Solutions from conservation biology. Smithso-nian Institution Press, Washington, DC.

Wiley, J. W., & B. N. Wiley. 1981. Breeding seasonecology and behavior of Ridgway’s Hawk (Buteoridgwayi). Condor 83: 132–151.

Wiley, J. W., & J. M. Wunderle, Jr. 1993. The effectsof hurricanes on island birds, with emphasis onthe Caribbean. Bird Conserv. Int. 3: 319–349.

Wimberger, P. H. 1984. The use of green plantmaterial in bird nests to avoid ectoparasites.Auk 101: 615–618.

Wittenberg, J. 1968. Freilanduntersuchungen zuBrutbiologie und Verhalten der Rabenkrähe(Corvus c. corone). Zool. Jahrb. Abt. Syst. Oekol.Geogr. Tiere 95: 16–146.

Woods, C. A., & J. A. Ottenwalder. 1983. Themontane avifauna of Haiti. Pp. 607–622 in Ris-ser, A. C., Jr., & F. S. Todd (eds.). Proceedingsof the Jean Delacour/IFCB Symposium onbreeding birds in captivity. International Foun-dation for the Conservation of Birds, LosAngeles, California.

Woods, C. A., & J. A. Ottenwalder. 1992. The natu-ral history of southern Haiti. Florida Museumof Natural History, Gainseville, Florida.

Württemberg, P. W. H. von. 1835. Erste Reise nachdem nordlichen America in den Jahren 1822bis 1824. J. G. Cotta, Stuttgart and Tübingen,Germany.

Zanoni, T. A., M. M. Mejía P., J. D. Pimentel B., &R. G. García G. 1990. La flora y la vegetaciónde Los Haitises, República Dominicana.Moscosoa 6: 46–98.

Zar, J. H. 1975. Biostatistical analysis. Prentice-Hall, Inc., Englewood Cliffs, New Jersey.

146

the ecology, behavior, and conservation of a west …

Documents