1973 SHORT COMMUNICATIONS 605

PREY OF THE ABYSSINIAN LONG-EARED OWL ASZO ABYSSZNZCUS

During an expedition to collect mammals in the Mendebo-Araenna Mountains of Bale Province, Ethiopia, a batch of owl pellets was found beneath a giant heath (Philippia sp.), in the Urgana Valley (c. 06" 57' N, 49" 45' E, alt. 3940 m). There are two large species of owl recorded in the area, and a single darker coloured owl seen in the Urgana Valley was tentatively identified as a Cape Eagle Owl Bubo capensis. There are however good grounds for attributing the pellets to the Abyssinian Long-eared Owl Asioabyssinicus ; a single primary feather found with the pellets matched in colour the primaries of a speci- men of this species, and more than 30 individuals were observed roosting in a grove of Philippia at Garba Garacha, about 12 km southeast of the Urgana Valley site. Little is known of the ecology of this owl, which is generally regarded as rather rare; Mackworth- Praed & Grant (1952, 'Birds of eastern and north eastern Africa,' 1 : 646) record " Food: No information ".

The pellets were found on 3 January 1972, and the roost was a current one (the expedition's botanist saw an owl depart). Despite this, the pellets were fragmented, and could not be measured or counted. The skeletal remains were extracted in the field by soaking the pellets in water. The cranial elements were subsequently identified at the British Museum (Natural History) (Mammal Section reg. nos. 72.1395 and 72.1399) by reference to the rest of our collections. Skulls, left dentaries and right dentaries were counted separately, and the highest of these three counts is given in Table 1. Post-cranial elements gave much lower counts, so there was no evidence of the owl dccapitating prey, and discarding the head, before swallowing it.

TABLE 1 Prey oj Asio abyssinicus compared with the results oj mammal collecting iii the I:rgana

Valley. Figures give the number of individuals.

Collections Average Pellet (trapped+, weight

contents shot') (6)

Crocidura fumosal Tachyoryctes splendens Tachyoryctes macrocephulus Arvicanthis blicki Stenocephalemys albocaudataa Lophuromys melanonyx Lophuromys flavopunctatus Otomys typus

13 c. 200 1 0

1 3' 1402 0 4" 118

92 5 3 0

40 112

3 7t 20 I t

14 5 t

2$ 74

There are two species of Crocidura at high altitude in Ethiopia, C. baileyi and C. fumosa. It is presumed that those

Not an average, but the weight of a juvenile of comparable age to that in the owl pellcts.

a Petter (1972 ' Mammalia ' 36 : 171-181) has recently described a second species of Stenn- All the owl pellet material, and probably all of those that we trapped in the Urgana

Their skulls seem indistinguishable, but the pelages are distinctive. from the owl pellets were, like all the shrews we trapped in the Urgana Valley, C. .fzcmnsa.

The adults weigh up to 950 g.

cephalemys. Valley, seem to be S. albocaudata.

The list of prey demonstrates three points of interest. The shrew Crocidura and the rats Otomys and Stenocephalemys, which seem to provide the bulk of the owl's prey, were species which we trapped overnight, mostly between dusk at 18.00 and 22.00 hours (a very heavy frost later each night probably deterred activity among small mammals). By far the most abundant rodents in this area were the giant mole rat Tachyoryctes macrocephalus, the field rat Arvicanthis blicki and the harsh-furred rat Lophuromys

606 CORRESPONDENCE IBIS 115

nzelanoityx, but we were unable to trap these, though we did shoot a few. It is probable that thesc three rodents are diurnal; the owls were certainly not feeding on them very much, despite their abundance. In fact, the results imply that the owl is a nocturnal hunter, as is the closely related Asio otuf in Britain.

Table 1 includes the average weights of the potential prey animals obtained in our collecting. For A. abyssinicus, the “ average prey animal ” weighs about 84 g, whereas the comparable figure for A. otus in Britain is 20 g (based on the results of Glue 1961, ‘ Mammal Review ’ 1 : 53-62, and South 1966, ‘ Brit. Birds ’ 59 : 493437). The larger prey may simply reflect the size of the owl, which is 16% larger than A. otus in wing-length.

Finally, these results emphasise again the value of owl pellets not only for the ornithologist but also for the mammalogist. Neither Otomys typus nor Stenocephalemys albocaudata, the main prey, are well represented in museums. The British Museum (Natural History) had only 13 Ethiopian examples of the former, from three localities, and only three of the latter (an endemic), each from a different place, before the present collections were made.

The second point of note concerns the size of the prey taken.

Department of Zoology, The University,

Manchester M13 9PL.

15 May 1973

D. W. YALDEN

CORRESPONDENCE

AERIAL FEEDING BY BULBULS

SIR,-h support of I l r Illeriwani’s comments on aerial feeding by bulbuls (1973, ‘ Ibis’ 115: 285), I would remark that I have observed aerial pursuit from a perch (bush or small tree) and capture of insects by Black-eyed Bulbuls Pycnonotus barbatus on a number of occasions in Rhodesia. The commonest prey obtained by this technique is the winged (alate) termite. On one occasion, in Salisbury, Black-eyed Bulbuls and large dragonflies (Odonata, probably Anax sp.) were both taking termite alates from the same swarm. Whenever a bulbul and a dragonfly headed for the same termite, the dragonfly gave way at the last moment and allowed the bulbul to capture it.

Durban Museum, Smith Street,

Durban, South Africa.

13 June 1973.

R. K. BROOKE

SIR,-DT Meriwani’s observation of aerial feeding by bulbuls (1973 ‘ Ibis ’ 115: 285) is not, in my experience, exceptional. Many are the times I have watched Yellow-vented Uulbuls Pycnonotus xanthopyRos, the commonest garden bird in Kampala, Uganda, as they dart and tumble in pursuit of insects, particularly winged termites. They are perhaps less agile than the true flycatchers, and they do not seem to have the flyc;tcher’s habit of hawking from the same perch.

I notice also that Rutgers (1969, ‘ Birds of Asia , Methuen: 285) noted that the Chinese Bulbul P. sinensis chases and catches insects in the air in a way that has something in common with the flycatchers.

34 South Drive, Upton,

Wirral,

1 August 1973 Cheshire.

DR J. P. STANFIELD