contrasting strategies of provisioning and chick growth in two sympatrically breeding albatrosses at...

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CONTRASTING STRATEGIES OF PROVISIONING AND CHICK GROWTHIN TWO SYMPATRICALLY BREEDING ALBATROSSES AT CAMPBELLISLAND NEW ZEALANDAuthor(s) Susan M Waugh Henri Weimerskirch Yyes Cherel and Peter A PrinceSource The Condor 102(4)804-813 2000Published By Cooper Ornithological SocietyDOI httpdxdoiorg1016500010-5422(2000)102[0804CSOPAC]20CO2URL httpwwwbiooneorgdoifull1016500010-5422282000291025B08043ACSOPAC5D20CO3B2

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[804]

The Condor 102804ndash813q The Cooper Ornithological Society 2000

CONTRASTING STRATEGIES OF PROVISIONING AND CHICKGROWTH IN TWO SYMPATRICALLY BREEDING ALBATROSSES

AT CAMPBELL ISLAND NEW ZEALAND1

SUSAN M WAUGH

NIWA PO Box 8602 Christchurch New Zealand and CEBC CNRS Beauvoir-sur-Niort 79360 France

HENRI WEIMERSKIRCH AND YYES CHEREL

CEBC CNRS Beauvoir-sur-Niort 79360 France

PETER A PRINCE2

British Antarctic Survey Natural Environment Research Council High Cross Madingley RoadCambridge CB3 OET United Kingdom

Abstract The provisioning strategies of two closely related species of albatross breedingsympatrically were studied at Campbell Island New Zealand Black-browed Albatrosses(Diomedea melanophrys) had a higher provisioning rate of chicks than Grey-headed Alba-trosses (D chrysostoma) as a result of a higher feeding frequency Provisioning and satellite-tracking data suggest that Black-browed Albatrosses forage over neritic waters in trips ofup to 5 days in combination with longer trips over oceanic waters In contrast it was notpossible to separate clearly short and long trips in Grey-headed Albatrosses but they prob-ably forage mostly over oceanic waters combined with rafting or feeding near the colonyduring stays of short duration at sea No inter-annual differences in foraging trip durationwere apparent between years for either species Chicks were fed larger meals at older agesand when in poorer condition probably due to a limitation on the rate of assimilation offood For both species chick condition after feeding did not influence the duration of for-aging trips Black-browed Albatrosses from Campbell Island feed locally in neritic watersand up to 2000 km from the colony in contrast to conspecifics from other sites which feedprincipally over neritic waters Grey-headed Albatrosses were largely dependent on oceanicresources as for conspecifics studied elsewhere This study shows that foraging and provi-sioning strategies are flexible within species allowing them to exploit more or less distantresources

Key words Black-browed Albatross chick growth Diomedea chrysostoma Diomedeamelanophrys foraging strategy Grey-headed Albatross provisioning

INTRODUCTION

The performance of seabirds in finding and de-livering food to their young can be measuredthrough their provisioning rate the net energydelivered during any given period (Schoener1971 1987) Although many aspects of a spe-ciesrsquo ecology may influence this rate it is nev-ertheless a sensitive indicator of performanceand may vary between species (Lack 1968) sea-sons and individuals (Weimerskirch et al 19951997a 1997b) Ultimately the provisioning rateaffects clutch size (Lack 1968) chick growthrate (Ricklefs 1968) survival of young andtherefore parental fitness (Clutton-Brock 1991)In Procellariiformes clutch size is one and thusvariation in provisioning performance can be

1 Received 28 July 1998 Accepted 6 July 20002 Deceased

measured directly by the food intake of a singlechick Even in closely related species of similarsize significant differences occur in the growthrate and chick-rearing period For example dif-ferences between Black-browed (Diomedea me-lanophrys) and Grey-headed Albatrosses (Dchrysostoma) in provisioning rate (Tickell andPinder 1975) and diet quality (Prince 1980) re-sult in a longer chick rearing period and biennialbreeding for Grey-headed Albatrosses (Prince etal 1994) Satellite telemetry studies have shownthat these species have species-specific foragingstrategies Black-browed Albatrosses at the Ker-guelen Islands feed exclusively on shelf areas(Cherel and Weimerskirch 1995 Weimerskirchet al 1997a) and move between two shelf areasat South Georgia (Prince et al 1997) Foragingalso is linked to the Polar Frontal Zone (PFZ)In comparison Grey-headed Albatrosses are sel-dom found over shelf areas around the Crozet

PROVISIONING IN TWO SYMPATRIC CLOSELY-RELATED ALBATROSSES 805

and Kerguelen Islands (Weimerskirch et al1988) and forage mainly over oceanic waters atSouth Georgia but also concentrate on part ofthe PFZ (Prince et al 1997)

Whether provisioning rate in seabirds is reg-ulated by chick needs or limited by adult energyregimes is unclear (Ricklefs 1992 Ricklefs andShew 1994 Hamer and Hill 1997) For somespecies there appears to be little relationship be-tween chick condition and adult foraging per-formance as meal sizes are independent of tripduration chick condition or meal mass (Hamerand Hill 1993 Hamer 1994) However for otherspecies the condition of chicks has some influ-ence on adult foraging strategies (Ricklefs et al1985) For example British Storm-Petrel (Hy-drobates pelagicus) adults return more quicklyto feed chicks in poorer condition (Bolton 1995)Recently differing modes of regulation havebeen linked to a speciesrsquo foraging strategy withneritic-only feeders having less ability to re-spond to chick needs than those species whichdivide their time between oceanic and neriticfeeding (Weimerskirch 1998)

Black-browed Albatrosses at Campbell Islandare on average 25 lighter than conspecificsfrom other sites (Waugh et al 1999a) and be-long to another sub-species (D m impavida)The fledging period takes longer at Campbell Is-land than at other sites (Tickell and Pinder 1975Weimerskirch et al 1997b) Grey-headed Alba-trosses have similar morphometry across sitesbut at Campbell Island the fledging period islonger than at South Georgia (Tickell and Pinder1975 Moore and Moffat 1990) These variationssuggest that between-site intra-specific differ-ences in foraging behavior may be considerableThe aims of this study are to examine whether(1) the provisioning and foraging strategies dif-fer between Black-browed and Grey-headed Al-batrosses at Campbell Island (2) the two speciesdiffer from birds at other sites as a result of ex-ploiting different environments (3) chickgrowth differs between species and years and(4) the performance of individual adults is re-lated to chick food requirements

METHODS

Foraging of Grey-headed and Black-browed Al-batrosses was studied at Campbell Island (528S1698E) New Zealand during the 1995ndash1996 and1996ndash1997 breeding seasons (hereafter 1996and 1997 respectively) Approximately 26000

pairs of Black-browed Albatrosses and 6000pairs of Grey-headed Albatrosses nest at the siteannually (P Moore unpubl data) The studycolony at Bull Rock South contains annually ap-proximately 8000 and 300 breeding pairs ofeach species respectively Several species of pe-trel also breed at the site but numbers have beengreatly diminished by the presence of rats (Rat-tus norvegicus) and cats (Felis domesticus) (Bai-ley and Sorensen 1962)

The study area contained birds of both speciesand these were observed continuously duringdaylight hours to estimate foraging and provi-sioning parameters One adult from each nestwas marked with a 5ndash10 cm band of picric acidon the breast during incubation and during thestudy period the identity of each visiting adultwas noted and its behavior observed continu-ously while it was at the colony along with itstimes of arrival and departure Chicks wereweighed to the nearest 50 g using a 10-kg Salterspring balance every day at 0400 1900 (Uni-versal Time 1 12 hr) and just after each feedgiving information about the meal mass and thegrowth rate of chicks All chicks studied sur-vived the study period

The study was undertaken in three periods 9ndash23 January 1996 9ndash23 January 1997 and 6ndash20February 1997 During the January 1996 andFebruary 1997 periods provisioning and forag-ing strategies and chick growth were examinedwhereas in January 1997 only chick growth wasmeasured Samples of 35 40 and 32 Black-browed Albatross chicks were used in January1996 January 1997 and February 1997 respec-tively along with 24 15 and 35 Grey-headedAlbatross chicks respectively for the same pe-riods

Chicks were aged during the 1997 seasonfrom their hatching dates Chicks from the twospecies were between 24ndash37 days old at the startof the January study period in 1997 During the1996 season hatching data were not availablebut we considered chicks to be of equivalent agebetween seasons as three seasons of hatchingdata showed maximum variation in the meanhatching date of only 4 days in Black-browedAlbatrosses and 3 days in Grey-headed Alba-trosses at Campbell Island (S Waugh and PMoore unpubl data) During the study periodschicks were in the rapid phase of growth (Rick-lefs 1973) and had not yet attained peak weightsFor these species chicks aged between 30ndash80

806 SUSAN WAUGH ET AL

days are in the t10ndash90 phase of growth (Tickelland Pinder 1975) which is the period requiredfor growth from 10 to 90 of asymptotic weight(Ricklefs 1973) During this phase growthcurves fitted to different equations can mostreadily be compared (Ricklefs 1973) hence weconsidered that comparison between the linearregressions of growth curves across groups tobe valid

Albatrosses feed their chicks by regurgitationthus whole food items cannot be counted andestimation of meal masses relies on weighingchicks to determine mass differences before andafter feeding It is necessary to take account ofthe mass chicks lose through respiration and def-ecation between feedings to estimate meal mas-ses (Ricklefs et al 1985) We estimated averagerates of mass-loss for chicks of each species bycalculating the proportion of body weight lostper hour during the first 6 hr 6ndash12 hr 12ndash24 hrand 24 hr or more after a feed The estimatedweight lost before each chicksrsquo feeding eventwas subtracted from its last pre-feed weight andthe difference between this value and the post-feed weight gave the estimated meal mass Dailyprovisioning rate was estimated using the aver-age meal mass delivered daily for each individ-ual adult

We estimated breeding success by weekly in-spections of nests from the beginning of incu-bation until 1 February in 1996 and 1997 exceptfor 10 November to 4 January in the 1996 sea-son when no visits were made

Satellite telemetry was carried out on sevenadult Black-browed and five adult Grey-headedAlbatrosses feeding chicks (see Waugh et al1999b) They were fitted with Toyocom 2038(55 g) and Microwave 100 (30 g) satellite trans-mitters following the methods of Weimerskirchet al (1997b) Ten and five foraging trips werefollowed respectively Satellite-tracking datawere analyzed using GIS ARC-INFO integratedwith bathymetric data Bathymetry was inter-polated from 500-m depth grids that were gen-erated by ARC-INFO from contour datasourced from the General Bathymetric Chart ofthe Oceans (GEBCO) (British OceanographicData Centre 1994) Five Black-browed and fourGrey-headed Albatrosses were fitted with 20-gtemperature-recorders at the tarsus These devic-es log the birdrsquos activity (Wilson et al 1995) andmeasure the sea-surface temperature (SST)thereby indicating in which water-mass birds

were foraging (Weimerskirch et al 1995) Weestimated minimum foraging ranges from theserecords by calculating the closest distance be-tween Campbell Island and the lowest (or high-est) temperatures recorded based on SST ac-cessed through the Integrated Global Ocean Ser-vices System (IGOSS) (Reynolds and Smith1992)

STATISTICAL ANALYSES

We tested for differences between breeding suc-cess the number of birds undertaking only ne-ritic trips between years or species using x2

tests Chick growth was examined using the re-gression of chick-mass upon date for each chickwith the slope of the equation indicating thegrowth rate Growth data from the beginningand the last 14 days of each study period gaveinitial masses and growth rates respectively andwere compared using students t-tests

Pre-feed chick condition was calculated foreach individual at each feeding-event by takingthe residuals of the linear regression on thechicks weight at that time After-feed conditionestimates are the residuals from the regressionof post-feed weights on time Meal mass andchick condition before and after feeding wereexamined in relation to the duration of foragingtrips and the time since the chicksrsquo previousmeal using Pearsonrsquos correlation Data for mealmass and the interval since the previous mealwere normalized with square root transforma-tions and foraging trip duration by a log trans-formation (Zar 1984)

Between species year and species 3 year in-teractions for the foraging parameters were test-ed using ANOVA with year and species as fac-tors Means and standard deviations are usedthroughout and for all statistical tests the levelof significance was 005

RESULTSBREEDING SUCCESS

There were significant inter-annual differencesfor Black-browed (breeding success 68 n 5101 and 87 n 5 100 respectively x2

1 5 101P 001) but not for Grey-headed Albatrosses(68 n 5 93 and 74 n 5 81 respectivelyx2

1 5 08) The differences in breeding successbetween the species were significant in 1997 (x2

1

5 49 P 5 002) but not 1996 (x21 5 01)

Hatching success details were not available for1996 but in 1997 fledging success (number of


FIGURE 1 Growth of Black-browed (BBA) andGrey-headed Albatross (GHA) chicks at Campbell Is-land studied during January 1996 and 1997 and Feb-ruary 1997 Linear regression lines are shown for eachgroup of chicks for Black-browed Albatrosses (Janu-ary 1996 y 5 863x 1 806 January 1997 y 5 873x1 1039 February 1997 y 5 355x 1 1733) and forGrey-headed Albatrosses (January 1996 y 5 660x 1789 January 1997 y 5 913x 1 751 February 1997y 5 103x 1 2450) Dotted lines indicate averageadult mass during the chick-rearing period

TABLE 1 Foraging parameters (x 6 SD [n]) of Grey-headed (GHA) and Black-browed Albatrosses (BBA)df 5 1 1 for all tests

Parameter Species January 1996 February 1997 Effect F P

No visits per nest per day

Duration of stay at the colony (hr)

BBAGHA

BBAGHA

114 6 028 (35)078 6 023 (24)

019 6 009 (69)049 6 078 (46)

099 6 022 (32)078 6 023 (15)

013 6 004 (63)015 6 007 (28)

speciesyearspecies 3 yearspeciesyearspecies 3 year

327202579

13957

0001nsns0010001002

Duration of foraging trip (days)

Meal mass (g)

Proportion of visits without chickbeing fed

BBAGHA

BBAGHA

BBAGHA

164 6 100 (68)216 6 126 (45)

393 6 78 (35)456 6 130 (24)

006 6 007 (35)003 6 006 (22)

164 6 071 (63)210 6 127 (28)

474 6 67 (32)542 6 104 (15)

002 6 005 (32)007 6 009 (24)

speciesyearspecies 3 yearspeciesyearspecies 3 yearspeciesyearspecies 3 year

1020100

116190

000004

114

001nsns00010001nsnsns0001

hatched chicks surviving to 1 February) was93 for Black-browed Albatrosses and 90 forGrey-headed Albatrosses

CHICK GROWTH

Growth rates were positive and differed signif-icantly from zero for all groups of chicks exceptGrey-headed Albatrosses in February 1997 (Fig1) Chick growth in the January periods showedno significant inter-annual differences for Black-browed Albatross but Grey-headed Albatrosschicks grew faster in the second year (t348 5230 P 5 001 t-tests with separate variancesthroughout this section) but did not have differ-ent initial weights (t528 5 202) Between thetwo species the masses of chicks at the begin-ning of the study periods varied in January 1996(t551 5 30 P 5 001) and January 1997 (t704 531 P 5 001) but not in February 1997 (t511 507) with Black-browed Albatross chicks beingheavier at the beginning of the periods Therewere no significant differences in growth ratebetween species in any period

NUMBER AND DURATION OF VISITS PER DAY

The average number of visits to nests per dayvaried between species but not between yearswith Black-browed Albatrosses visiting morefrequently (Table 1) The duration of visits to thecolony showed species year and species 3 yeareffects Black-browed Albatrosses stayed forshorter times at the colony than Grey-headed Al-batrosses during both years and for both spe-


FIGURE 2 The distribution of foraging trip dura-tions for Black-browed (BBA) and Grey-headed Al-batrosses (GHA) averaged over two seasons

FIGURE 3 Relationship between the maximumrange and duration of individual foraging trips forBlack-browed (BBA) and Grey-headed Albatrosses(GHA) Circles 5 satellite tracked birds squares 5birds with temperature-recorders

cies the duration of stays were shorter in 1997than 1996 (Table 1)

FORAGING TRIP DURATIONS

The distributions of the duration of foragingtrips were positively skewed for both specieswith an abundance of short trips (Fig 2) Meantrip duration showed significant differences be-tween species only (Table 1) Black-browed Al-batrosses were undertaking shorter trips on av-erage than Grey-headed Albatrosses The distri-bution of maximum foraging ranges from thecolony of birds fitted with satellite-trackers ortemperature-loggers indicates that for Black-browed Albatrosses (n 5 12 birds) trips of lessthan 5 days duration came from birds travellingto less than 600 km at maximum range from thecolony (Fig 3) For these trips the water depthsat the maximum ranges were less than 1000 mindicating that birds were foraging exclusivelyover the Campbell Plateau during these shorttrips Longer trips were over deep waters (2ndash7km depth) Based on these findings for subse-quent analyses we divided foraging trips byBlack-browed Albatrosses into neritic trips of 0ndash5 days duration and oceanic trips of greater than5 days For Grey-headed Albatrosses the divi-sion between neritic and oceanic trips was un-clear (n 5 9 birds Fig 3) Satellite-trackedGrey-headed Albatrosses foraged over deep wa-ters during 3-day trips Additionally for this

species a high number of short foraging trips(Fig 2) was recorded from the provisioning-ratestudy we were unable to discern whether thesewere foraging trips on the Campbell Plateau orsimply birds resting at sea near the colony be-tween attempts to feed chicks

NERITIC AND OCEANIC TRIPS

For Black-browed Albatrosses neritic trips werepredominant in the foraging strategy with 86(n 5 69) and 85 (n 5 63) of visits to the chickfollowing these trips in 1996 and 1997 respec-tively The proportion of birds which undertookonly neritic trips (1996 49 1997 34) didnot differ significantly between years (x2

1 5 22P 01) The maximum numbers of successiveneritic trips for Black-browed Albatrosses were16 and 9 in 1996 and 1997 respectively Meandurations of neritic foraging trips (1996 x 6 SD5 13 6 04 days n 5 90 1997 13 6 06 daysn 5 63) and oceanic trips (1996 71 6 13 days


n 5 35 1997 72 6 11 days n 5 21) showedno significant differences between years forBlack-browed Albatrosses (204 t 06)Black-browed Albatrosses delivered 14 6 22(n 5 69) of meals after long trips in 1996 and15 6 17 (n 5 63) in 1997 The proportion oftime birds spent in long trips was 33 6 36 (n5 69) in 1996 and 40 6 31 (n 5 63) in 1997There were no significant inter-annual differenc-es in either of these parameters

For Grey-headed Albatrosses trips were notdivided into oceanic and neritic trips for analy-sis However some birds performed successivetrips of less than 3 days duration in 1996 (2)and 1997 (3) The maximum number of suc-cessive trips of this length was 10 and 8 re-spectively for the same years

MEAL MASS

Meal masses differed between years and specieswith Grey-headed Albatross chicks receivinglarger meals than Black-browed Albatrosschicks in both years and meals delivered in Feb-ruary 1997 being larger than those from January1996 in both species (Table 1) The occurrenceof chicks receiving no meal during an adultrsquosvisit showed no differences between years andspecies (Table 1) However there was a signifi-cant species 3 year effect due to a decrease inthe proportions between years for Black-browedAlbatrosses and an increase for Grey-headedAlbatrosses Meal mass increased with date forGrey-headed Albatrosses in both 1996 (r 5 030n 5 167 P 0001) and 1997 (r 5 023 n 5120 P 5 001) but not for Black-browed Al-batrosses (1996 r 52001 n 5 385 1997 r 5006 n 5369)

INFLUENCE OF CHICK CONDITION ON ADULTPROVISIONING

The mass of meals delivered was inversely re-lated to chick condition before feeding forBlack-browed and Grey-headed Albatrosses in1996 (r 5 2044 n 5 385 P 0001 r 52040 n 5 167 P 0001 respectively) and1997 (r 5 2046 n 5 369 P 0001 r 52044 n 5 120 P 0001 respectively) Inaccord with this meal mass increased with thetime since chicks were last fed in the two speciesin 1996 (Black-browed Albatrosses n 5 385 r5 022 P 0001 Grey-headed Albatrosses n5 167 r 5 028 P 0001) and 1997 (Black-browed Albatrosses n 5 369 r 5 030 P

0001 Grey-headed Albatrosses n 5 120 r 5032 P 5 0001)

The mass of the meal increased with the du-ration of foraging trips for Grey-headed Alba-trosses in 1996 (r 5 018 n 5 141 P 5 004)and 1997 (r 5 025 n 5 108 P 001) ForBlack-browed Albatrosses meal mass did notshow a strong relationship with trip duration ineither year (1996 r 5 2010 n 5 359 P 5005 1997 r 5 004 n 5 340) The conditionof the chicks of both species after feeding hadno influence on the duration of the subsequenttrip in 1996 (four tests 003 r 016)

DAILY PROVISIONING BY ADULTS

For Black-browed Albatrosses the daily provi-sioning rate by adults was 141 6 73 g day21 (n5 70) in 1996 and 183 6 74 g day21 (n 5 63)in 1997 For Grey-headed Albatrosses the av-erage rate was 108 6 58 g day21 in 1996 (n 546) and 157 6 62 g day21 (n 5 28) in 1997Provisioning rates were significantly higher inthe second year of study (F1105 5 194 P 0001) and higher for Black-browed than Grey-headed Albatrosses (F1105 5 87 P 001) butthere was no interaction effect (F1105 5 02)

DISCUSSION

FORAGING AND PROVISIONING STRATEGIESAT CAMPBELL ISLAND

Black-browed and Grey-headed Albatross for-aging strategies at Indian and Atlantic Oceansub-Antarctic sites have been characterized asneritic and oceanic respectively (Weimerskirchet al 1986 1988 1997b Cherel and Weimer-skirch 1995 Prince et al 1997) The more di-verse foraging strategies found in Black-browedAlbatrosses from Campbell Island howevershow this species is capable of adapting greatlyto the environmental characteristics surroundingits breeding sites

Satellite tracking of Black-browed Albatross-es from Campbell Island suggests that they di-vided their time between the extensive CampbellPlateau and oceanic foraging trips up to 2000km from their breeding site mainly to the PFZor to the east of the Campbell Plateau (Waughet al 1999b) Birds were evidently undertakingtwo types of foraging trips trips of less than 5days duration that are exclusively over shelf wa-ters (neritic trips) and longer foraging trips overoceanic waters Most individuals followed inthis study carried out both long and short for-


aging trips thus were exploiting both foragingenvironments Such a combination of strategieshas been well established for several other Pro-cellariiform species and is thought to allow pe-lagic seabirds to rely on distant resources tofledge their chicks (Weimerskirch et al 19931995 1997b Weimerskirch 1998) Use of twocontrasting foraging strategies by Black-browedAlbatrosses has not been demonstrated before Italso is a novel finding that a seabird species useseither exclusively neritic or a mixture of neriticand oceanic foraging strategies depending on thesite of origin

In contrast Grey-headed Albatrosses occurrarely over shelf waters at other sites and arethought to feed mainly over deeper waters (Wei-merskirch et al 1986 1988 Prince et al 1997)Consistent with this satellite-tracked birds fromCampbell Island traveled to oceanic water evenwhen undertaking relatively short trips (3 daysWaugh et al 1999b) However birds followedin the provisioning study commonly undertookshort trips (less than 2 days) Average daily dis-tances of travel for satellite-tracked Grey-headedAlbatrosses suggest that these trips would bewithin 400ndash500 km range of Campbell Islandover the Campbell Plateau suggesting thatGrey-headed Albatrosses could spend a signifi-cant proportion of their time feeding over shelfwaters Some birds performed up to 10 trips ofless than 3 days duration successively suggest-ing that foraging relatively close to the colonymay be important for some individuals

These different foraging strategies are reflect-ed in the differing chick-provisioning strategiesof the two species at Campbell Island Grey-headed Albatrosses delivered larger meals lessoften than Black-browed Albatrosses althoughthe result was a lower provisioning rate than forBlack-browed Albatrosses

DIFFERENCES BETWEEN YEARS ATCAMPBELL ISLAND

The two years represented favorable breedingseasons at Campbell Island with breeding suc-cess above the median recorded for six previousyears of study (Waugh et al 1999c) Slight inter-specific differences in breeding success were ap-parent with Black-browed Albatrosses havinghigher overall breeding success in 1996 than1997 and having significantly higher breedingsuccess than Grey-headed Albatrosses in 1997Thus it would appear in the slightly poorer year

(1997) Grey-headed Albatrosses had relativelygreater difficulty in raising chicks than Black-browed Albatrosses Some inter-annual differ-ences in foraging and provisioning strategiescould be accounted for by the fact that chickswere about 28 days older in the second year ofstudy

For Black-browed Albatrosses the olderchicks of the second year were provisioned at ahigher rate with larger meal masses presumablydue to greater energy needs of older comparedto younger chicks In addition for older chicksa lower proportion was not fed during visits andcolony-visits were shorter These factors suggesta limitation in the ability of small chicks to re-ceive meals and is consistent with the findingsof other studies which showed that in storm pe-trels (Ricklefs 1992) and Black-browed Alba-tross (Weimerskirch et al 1997b) meal sizescould be influenced by the chickrsquos ability to as-similate food Despite the age difference inchicks the foraging strategies of Black-browedAlbatrosses did not differ between years withbirds undertaking similar proportions of neriticand oceanic trips and trips were of similar av-erage duration These results indicate that atleast for neritic foraging trips which form themajority of trips for this species birds may beexploiting a food source which does not vary inlocation between years as for conspecifics atKerguelen Island (Weimerskirch et al 1997b)The lack of increase in meal sizes during eachtwo-week study period for this species furtherindicates a limitation on foraging perhaps be-cause birds have fixed commuting times andthus return to the colony with whatever they findduring the hours available for foraging Chickgrowth in January was similar between years forBlack-browed Albatrosses This may result froman intrinsic growth rate (Prince and Ricketts1981) andor similar feeding conditions betweenyears

Similar inter-annual patterns in foraging andchick provisioning were evident for Grey-head-ed Albatrosses with no detectable differences inthe mean duration of foraging trips betweenyears Older chicks were provisioned at a higherrate as meals were larger and the durations ofstay at the colony by adults were longer foryounger chicks Chick growth showed more in-ter-annual variation in this species not differingsignificantly from zero in the second year A re-liance on different and more distant food sources


could explain these differences compared toBlack-browed Albatrosses Meal sizes increasedduring each two-week period again suggestingdifferences in food availability compared toBlack-browed Albatrosses

REGULATION VERSUS LIMITATION

A variety of provisioning responses by adultProcellariiformes has been described (Ricklefs etal 1985 Bolton 1995 Weimerskirch et al1997a 1997b) In some studies adults provi-sioned independently of chick needs suggestingan intrinsic rhythm in adult visitation (Ricklefs1992 Hamer and Hill 1993 Ricklefs and Shew1994) The long inter-feed interval by individualadults produces a high probability of a visit bythe birdrsquos partner between successive feedsTherefore chick condition after a meal conveysrelatively little information about what thechickrsquos needs will be when the adult returns afterits subsequent foraging trip (Ricklefs 1992) Inother studies adults adjusted their provisioningrates returning more quickly to feed chicks inpoorer condition although they were unable todeliver larger meals (Bolton 1995 Weimerskirchet al 1995) For Black-browed Albatrosses atthe Kerguelen Islands birds responded to ex-perimental overfeeding of chicks by the length-ening of foraging trips thus provisioning at low-er rates when chicks were in good condition(Weimerskirch et al 1997b) However the con-verse did not applymdashunderfed chicks receivedonly slightly larger meals at the same rate aschicks at control nests The ability of adults ofdifferent species to regulate their provisioningappears linked to their species-specific foragingstrategies Species with oceanic foraging habitsare able to increase their provisioning rates byincreasing the proportion of foraging trips innear-shore areas (Weimerskirch et al 1995) Forspecies which use a single strategy of short fre-quent trips as is typical for Black-browed Al-batrosses at sites other than Campbell Island andfor other neritic feeders the ability to increasethe frequency of feeds is limited and birds mayregulate provisioning of chicks in a limited wayby the size of meals rather than the duration oftrips (Weimerskirch et al 1997b)

We investigated the relationships betweenchick condition meal size and foraging trip du-ration to test whether the study species were in-fluenced by chick needs in the same ways BothBlack-browed and Grey-headed Albatrosses de-

livered larger meals to chicks in poorer condi-tion and to chicks that had fasted longer sincetheir last meal indicating that they could re-spond to the nutritional status of their chick bygiving more food The ability of chicks to con-sume larger meals when they are in poorer con-dition is likely to be the mechanism explainingthese results as recently fed chicks did not takelarge meals from their parents In both speciesadults did not respond to the condition of chicksafter a feed as there was no relationship be-tween this factor and the duration of the subse-quent foraging trip Here Black-browed andGrey-headed Albatrosses show similar responsesto other petrel (Ricklefs 1992 Hamer and Hill1994) and albatross species (Weimerskirch et al1997a)

Provisioning strategies of the two species dif-fered both in duration of foraging trips and themeal-mass delivered For Black-browed Alba-trosses the size of the meal brought to chicksshowed no relationship to the duration of theforaging trip in either year indicating that mealsize is determined by the adultrsquos foraging suc-cess In some species adults return to feed theirchick after attaining a threshold quantity of food(Bolton 1995) whereas in other species they re-turn regardless of the amount of food obtained(Weimerskirch et al 1997a) At Campbell Is-land a significant proportion of meals is deliv-ered after neritic trips by Black-browed Alba-trosses For Grey-headed Albatrosses the size ofmeals delivered was proportional to the durationof the previous foraging trip By relying on moredistant resources meals were delivered less fre-quently and therefore chicks were more oftenless replete and so able to receive bigger meals

COMPARISON AMONG SITES

The length of the chick rearing period of the twospecies differs among sites It is longest atCampbell Island 130 days and 152 days forBlack-browed and Grey-headed Albatrosses re-spectively (Moore and Moffat 1990) and isshortest at South Georgia 116 days and 141days for the two species respectively (Tickelland Pinder 1975) At the Kerguelen IslandsBlack-browed Albatross chicks fledge in 120days (Weimerskirch et al 1997b) The longfledging period for Black-browed Albatrosses atCampbell Island is paradoxical as adults aresmaller at this site (Waugh et al 1999a)

The plasticity in foraging behavior of Black-


browed Albatrosses between sites indicates thatthe marine environment adjacent to sites has animportant influence on the ecology of this spe-cies The physical oceanographic environmentsdiffer greatly between the sites Black-browedAlbatrosses at the Kerguelen and Crozet Islandsmainly use the shelf areas adjacent to the is-lands and rarely forage over deep waters (Wei-merskirch et al 1986 1997b Cherel and Wei-merskirch 1995) At South Georgia this speciesexploits rich but seasonally-variable krill stocksfeeding over shelves close to South Georgia andthe South Orkney Islands (Prince et al 1997)The PFZ passes relatively close to South Geor-gia (Peterson and Whitworth 1994) and is lo-cated at the Kerguelen Islands (Park et al 1993)At Campbell Island there is a more extensiveshelf area than at other sites and likely associ-ated fish-stocks Despite this Campbell Islandbirds undertaking long foraging trips travel upto 2000 km to the PFZ and other deep waterareas and thus are travelling farther than con-specifics which undertake only neritic feedingtrips Therefore at Campbell Island Black-browed Albatrosses behave more like an oceanicfeeding species with the lengthened chick-rear-ing period a probable result Grey-headed Al-batrosses appear to follow similar foraging strat-egies to conspecifics at other sites and relymainly on oceanic resources

This study has shown a clear division of for-aging strategies into neritic and oceanic foragingtrips for Black-browed Albatrosses breeding atCampbell Island It highlights the flexibility offoraging and provisioning strategies within thesame species foraging in different environmentalconditions For Grey-headed Albatrosses theforaging strategy is principally oceanic It is un-clear whether this species also relies on resourc-es from the Campbell Plateau Further satellite-tracking and provisioning studies are needed toexamine this question

ACKNOWLEDGMENTS

The project was funded by the Department of Conser-vation including the Conservation Services Levy paidby the New Zealand Commercial Fishing Industry Na-tional Institute of Water and Atmosphere Centre Na-tional de la Recherche Scientifique and the FrenchForeign Ministry For assistance in the field we thankG Hedley S Kalish B Thompson T Troup P Car-naby A Relling and E Abraham We are grateful tothe Department of Conservation staff at SouthlandConservancy for logistical support and S Ude P Sa-

gar and British Antarctic Survey for assistance withthe satellite tracking program We thank A WeathersD Anderson G Robertson K Hamer I West andtwo anonymous referees for comments on the manu-script

LITERATURE CITED

BAILEY A M AND J H SORENSEN 1962 SubantarcticCampbell Island Proc Denver Mus Nat Hist 101ndash301

BOLTON M 1995 Food delivery to nestling storm pe-trels limitation or regulation Funct Ecol 9161ndash170

BRITISH OCEANOGRAPHIC DATA CENTRE 1994 Generalbathymetric chart of the oceans British Oceano-graphic Data Centre Birkenhead UK

CHEREL Y AND H WEIMERSKIRCH 1995 Seabirds asindicators of marine resources Black-browed Al-batrosses feeding on ommastrephid squids in Ker-guelen waters Mar Ecol Prog Ser 129295ndash300

CLUTTON-BROCK T H 1991 The evolution of parentalcare Princeton Univ Press Princeton NJ

HAMER K C 1994 Variability and stochasticity ofmeal size and feeding frequency in the LittleShearwater Puffinus assimilis Ibis 136271ndash278

HAMER K C AND J K HILL 1993 Variation andregulation of meal size and feeding frequency inCoryrsquos Shearwater Calonectris diomedea JAnim Ecol 62441ndash450

HAMER K C AND J K HILL 1994 The regulationof food delivery to nestling Coryrsquos ShearwaterCalonectris diomedea the roles of parent and off-spring J Avian Biol 25198ndash204

HAMER K C AND J K HILL 1997 Nestling obesityand variability of food delivery in Manx Shear-waters Puffinus puffinus Funct Ecol 11489ndash497

LACK D 1968 Ecological adaptations for breeding inbirds Methuen London

MOORE P J AND R D MOFFAT 1990 Mollymawkson Campbell Island Science and Research Inter-nal Report 59 Dept Conserv Wellington NewZealand

PARK Y H L GAMBERONI AND E CHARRIAUD 1993Frontal structure water masses and circulation inthe Crozet Basin J Geophys Res 9812361ndash12385

PETERSON R G AND T WHITWORTH 1989 The sub-antarctic and polar fronts in relation to deep watermasses through the southwest Atlantic J Geo-phys Res 9410817ndash10838

PRINCE P A 1980 The food and feeding ecology ofthe Grey-headed Albatross Diomedea chrysosto-ma and Black-browed Albatross DmelanophrisIbis 122476ndash488

PRINCE P A J P CROXALL AND A G WOOD 1997The pelagic distribution of South Georgia alba-trosses and their relationships with fisheries p137ndash167 In G Robertson [ED] Albatross ecologyand conservation Surrey Beatty and Sons Chip-ping Norton Australia

PRINCE P A AND C RICKETTS 1981 Relationshipsbetween food supply and growth in albatrosses


an interspecies cross-fostering experiment OrnisScand 12207ndash210

PRINCE P A ROTHERY P J P CROXALL AND A GWOOD 1994 Population dynamics of Black-browed and Grey-headed Albatrosses Diomedeamelanophris and D chrysostoma at Bird IslandSouth Georgia Ibis 13650ndash71

REYNOLDS R W AND T M SMITH 1992 Improvedglobal sea-surface temperature analyses J Cli-mate 7929ndash948

RICKLEFS R E 1968 Patterns of growth in birds Ibis110419ndash451

RICKLEFS R E 1973 Patterns of growth in birds IIGrowth rate and mode of development Ibis 115177ndash201

RICKLEFS R E 1992 The roles of parent and chick indetermining feeding rates in Leachrsquos storm-petrelAnim Behav 43895ndash906

RICKLEFS R E C H DAY D E HUNTINGTON AND

J B WILLIAMS 1985 Variability in the feedingrate and meal size of Leachrsquos storm petrel at KentIsland New Brunswick J Anim Ecol 54883ndash898

RICKLEFS R E AND W A SHEW 1994 Foraging sto-chasticity and lipid accumulation by nestling pe-trels Funct Ecol 8159ndash170

SCHOENER T W 1971 Theory of feeding strategiesAnnu Rev Ecol Syst 2369ndash404

SCHOENER T W 1987 A brief history of optimal for-aging theory p 5ndash99 In A C Kamil J Krebsand H R Pulliam [EDS] Foraging behavior Ple-num Press New York

TICKELL W L N 1970 Biennial breeding in alba-trosses p 549ndash557 In M W Holdgate [ED] Ant-arctic ecology Vol 1 Academic Press London

TICKELL W L N AND R PINDER 1975 Breeding bi-ology of the Black-browed Albatross Diomedeamelanophris and Grey-headed Albatross D chry-sostoma at Bird Island South Georgia Ibis 117432ndash451

WAUGH S M P A PRINCE AND H WEIMERSKIRCH1999a Geographical variation in morphometry ofBlack-browed and Grey-headed Albatrosses atfour sites Polar Biol 22189ndash194

WAUGH S M H WEIMERSKIRCH Y CHEREL USHANKAR P A PRINCE AND P M SAGAR 1999bExploitation of the marine environment by two

sympatric albatrosses in the Pacific SouthernOcean Mar Ecol Progr Ser 177243ndash254

WAUGH S M H WEIMERSKIRCH P J MOORE AND PM SAGAR 1999c The population dynamics ofBlack-browed and Grey-headed Albatrosses Di-omedea melanophrys and D chrysostoma atCampbell Island 1942ndash1996 Ibis 141216ndash225

WEIMERSKIRCH H 1998 How can a pelagic seabirdprovision its chick when relying on a distant re-source Cyclic attendance foraging decision andbody condition in sooty shearwaters J AnimEcol 6699ndash109

WEIMERSKIRCH H J A BARTLE P JOUVENTIN AND JC STAHL 1988 Foraging ranges and partitioningof feeding zones in three species of southern al-batrosses Condor 90214ndash219

WEIMERSKIRCH H O CHASTEL AND L ACKERMAN1995 Adjustment of parental effort to manipulat-ed foraging ability in pelagic seabird the thin-billed prion Pachyptila belcheri Behav Ecol So-ciobiol 3611ndash16

WEIMERSKIRCH H O CHASTEL T CHAURAND L ACK-ERMAN X HINDERMEYER AND J JUDAS 1994Atlternative long and short foraging trips in pe-lagic seabird parent Anim Behav 47472ndash476

WEIMERSKIRCH H Y CHEREL F CUENOT-CHAILLETAND V RIDOUX 1997a Alternative foraging strat-egies and resource allocation by male and femalealbatrosses Ecology 782051ndash2063

WEIMERSKIRCH H P JOUVENTIN AND J C STAHL1986 Comparative ecology of the six albatrossspecies breeding on the Crozet Islands Ibis 128195ndash213

WEIMERSKIRCH H T MOUGEY AND X HINDERMEYER1997b Foraging and provisioning strategies ofblack-browed albatrosses in relation to the re-quirements of the chick natural variation and ex-perimental study Behav Ecol 8635ndash643

WEIMERSKIRCH H M SALAMOLARD F SARRAZIN AND

P JOUVENTIN 1993 Foraging strategy of Wander-ing Albatrosses through the breeding season astudy using satellite telemetry Auk 110325ndash342

WILSON R P H WEIMERSKIRCH AND P LYS 1995 Adevice for measuring seabird activity at sea JAvian Biol 26172ndash176

ZAR J H 1984 Biostatistical analysis 2nd ed Pren-tice-Hall London

[804]

The Condor 102804ndash813q The Cooper Ornithological Society 2000

CONTRASTING STRATEGIES OF PROVISIONING AND CHICKGROWTH IN TWO SYMPATRICALLY BREEDING ALBATROSSES

AT CAMPBELL ISLAND NEW ZEALAND1

SUSAN M WAUGH

NIWA PO Box 8602 Christchurch New Zealand and CEBC CNRS Beauvoir-sur-Niort 79360 France

HENRI WEIMERSKIRCH AND YYES CHEREL

CEBC CNRS Beauvoir-sur-Niort 79360 France

PETER A PRINCE2

British Antarctic Survey Natural Environment Research Council High Cross Madingley RoadCambridge CB3 OET United Kingdom

Abstract The provisioning strategies of two closely related species of albatross breedingsympatrically were studied at Campbell Island New Zealand Black-browed Albatrosses(Diomedea melanophrys) had a higher provisioning rate of chicks than Grey-headed Alba-trosses (D chrysostoma) as a result of a higher feeding frequency Provisioning and satellite-tracking data suggest that Black-browed Albatrosses forage over neritic waters in trips ofup to 5 days in combination with longer trips over oceanic waters In contrast it was notpossible to separate clearly short and long trips in Grey-headed Albatrosses but they prob-ably forage mostly over oceanic waters combined with rafting or feeding near the colonyduring stays of short duration at sea No inter-annual differences in foraging trip durationwere apparent between years for either species Chicks were fed larger meals at older agesand when in poorer condition probably due to a limitation on the rate of assimilation offood For both species chick condition after feeding did not influence the duration of for-aging trips Black-browed Albatrosses from Campbell Island feed locally in neritic watersand up to 2000 km from the colony in contrast to conspecifics from other sites which feedprincipally over neritic waters Grey-headed Albatrosses were largely dependent on oceanicresources as for conspecifics studied elsewhere This study shows that foraging and provi-sioning strategies are flexible within species allowing them to exploit more or less distantresources

Key words Black-browed Albatross chick growth Diomedea chrysostoma Diomedeamelanophrys foraging strategy Grey-headed Albatross provisioning

INTRODUCTION

The performance of seabirds in finding and de-livering food to their young can be measuredthrough their provisioning rate the net energydelivered during any given period (Schoener1971 1987) Although many aspects of a spe-ciesrsquo ecology may influence this rate it is nev-ertheless a sensitive indicator of performanceand may vary between species (Lack 1968) sea-sons and individuals (Weimerskirch et al 19951997a 1997b) Ultimately the provisioning rateaffects clutch size (Lack 1968) chick growthrate (Ricklefs 1968) survival of young andtherefore parental fitness (Clutton-Brock 1991)In Procellariiformes clutch size is one and thusvariation in provisioning performance can be

1 Received 28 July 1998 Accepted 6 July 20002 Deceased

measured directly by the food intake of a singlechick Even in closely related species of similarsize significant differences occur in the growthrate and chick-rearing period For example dif-ferences between Black-browed (Diomedea me-lanophrys) and Grey-headed Albatrosses (Dchrysostoma) in provisioning rate (Tickell andPinder 1975) and diet quality (Prince 1980) re-sult in a longer chick rearing period and biennialbreeding for Grey-headed Albatrosses (Prince etal 1994) Satellite telemetry studies have shownthat these species have species-specific foragingstrategies Black-browed Albatrosses at the Ker-guelen Islands feed exclusively on shelf areas(Cherel and Weimerskirch 1995 Weimerskirchet al 1997a) and move between two shelf areasat South Georgia (Prince et al 1997) Foragingalso is linked to the Polar Frontal Zone (PFZ)In comparison Grey-headed Albatrosses are sel-dom found over shelf areas around the Crozet





METHODS





















1

5 49 P 5 002) but not 1996 (x21 5 01)








BBAGHA

BBAGHA

114 6 028 (35)078 6 023 (24)

019 6 009 (69)049 6 078 (46)

099 6 022 (32)078 6 023 (15)

013 6 004 (63)015 6 007 (28)


327202579

13957

0001nsns0010001002


Meal mass (g)


BBAGHA

BBAGHA

BBAGHA

164 6 100 (68)216 6 126 (45)

393 6 78 (35)456 6 130 (24)

006 6 007 (35)003 6 006 (22)

164 6 071 (63)210 6 127 (28)

474 6 67 (32)542 6 104 (15)

002 6 005 (32)007 6 009 (24)


1020100

116190

000004

114



CHICK GROWTH

















MEAL MASS








DISCUSSION


























ACKNOWLEDGMENTS



LITERATURE CITED


















































METHODS





















1

5 49 P 5 002) but not 1996 (x21 5 01)








BBAGHA

BBAGHA

114 6 028 (35)078 6 023 (24)

019 6 009 (69)049 6 078 (46)

099 6 022 (32)078 6 023 (15)

013 6 004 (63)015 6 007 (28)


327202579

13957

0001nsns0010001002


Meal mass (g)


BBAGHA

BBAGHA

BBAGHA

164 6 100 (68)216 6 126 (45)

393 6 78 (35)456 6 130 (24)

006 6 007 (35)003 6 006 (22)

164 6 071 (63)210 6 127 (28)

474 6 67 (32)542 6 104 (15)

002 6 005 (32)007 6 009 (24)


1020100

116190

000004

114



CHICK GROWTH

















MEAL MASS








DISCUSSION


























ACKNOWLEDGMENTS



LITERATURE CITED





























































1

5 49 P 5 002) but not 1996 (x21 5 01)








BBAGHA

BBAGHA

114 6 028 (35)078 6 023 (24)

019 6 009 (69)049 6 078 (46)

099 6 022 (32)078 6 023 (15)

013 6 004 (63)015 6 007 (28)


327202579

13957

0001nsns0010001002


Meal mass (g)


BBAGHA

BBAGHA

BBAGHA

164 6 100 (68)216 6 126 (45)

393 6 78 (35)456 6 130 (24)

006 6 007 (35)003 6 006 (22)

164 6 071 (63)210 6 127 (28)

474 6 67 (32)542 6 104 (15)

002 6 005 (32)007 6 009 (24)


1020100

116190

000004

114



CHICK GROWTH

















MEAL MASS








DISCUSSION


























ACKNOWLEDGMENTS



LITERATURE CITED




















































BBAGHA

BBAGHA

114 6 028 (35)078 6 023 (24)

019 6 009 (69)049 6 078 (46)

099 6 022 (32)078 6 023 (15)

013 6 004 (63)015 6 007 (28)


327202579

13957

0001nsns0010001002


Meal mass (g)


BBAGHA

BBAGHA

BBAGHA

164 6 100 (68)216 6 126 (45)

393 6 78 (35)456 6 130 (24)

006 6 007 (35)003 6 006 (22)

164 6 071 (63)210 6 127 (28)

474 6 67 (32)542 6 104 (15)

002 6 005 (32)007 6 009 (24)


1020100

116190

000004

114



CHICK GROWTH

















MEAL MASS








DISCUSSION


























ACKNOWLEDGMENTS



LITERATURE CITED



























































MEAL MASS








DISCUSSION


























ACKNOWLEDGMENTS



LITERATURE CITED




































































ACKNOWLEDGMENTS



LITERATURE CITED














































contrasting strategies of provisioning and chick growth in two sympatrically breeding albatrosses at...

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