BIRDS OF P R E Y I N CAPTIVITY

5 reeding the G riff on vu It u re

at La Flbche Zoo Gyps fulz11rs

J A CQUE S BOU I L L A U L T Director, Parc Zoologique du Tertre Rouge, La FIPcke, France

Upon their arrival at our zoo the pair of Griffon vultures Gyps fulvus were thought to be about three to four years old, judging from their plumage. We do not know their country of origin as we received them from itinerants who exhibited them in wired cages with a volume of about one cubic metre. As the mesh had been nailed to the frame- work after the bird had been put into the cage, very rough cleaning only was possible through the small space left for feeding and watering the birds at the base of the cage. Thus, over a period of many months, these birds had never had a chance to perch, to bathe or even to half open their wings. Fortunately the Griffon vulture is a quiet, adapt- able bird and we were able to remove them from their cages with their plumage only a little ruffled. Their first reaction when put into a medium sized aviary was to stretch their wings and then flap them vigorously for a long time. As the Griffon vulture generally lives in small colonies there were no problems when we put the birds together; they settled down in a few days, rubbing each other’s head and neck with their beaks. -4 few good baths, several showers - downpours

are not rare in the west of France - and I had in my collection two presentable Griffon vultures as representatives of the fauna of France, since this species of vulture still lives and breeds in the Pyrenees.

We now have a birds of prey aviary of 2,700 m3 (95,350 ft3), but in 1960 this was not available and I decided to exhibit a group of clipped-winged eagles and vultures in a single enclosure. With trees, stumps, a pool and shelter available the birds - which included Imperial eagles Aquila rapax, Golden eagles A. chrysaetos, White-tailed sea eagles Haliaeetus albicilla, African fish eagles Haliaeetus vocifer, Vulturine fish eagles Gypo- kierax angolensis and Griffon vultures Gyps fulvus - established their territories and organised their social life right from the start. However, eventu- ally the Vulturine and African fish eagles had to

be removed because of the danger of frost-bitten feet during the winter.

At the end of the winter of 1962-63 a tornado passed through the zoo leaving the enclosure littered with the branches and needles of conifer. The Griffon vultures became very excited and collected beakfuls of this debris but, not knowing what to do with it, piled it first in one place then in another. We quickly built a boarded platform about I mz (3 ftz) in extent and I m (3 ft) above the ground in the shelter of one of the sheds. On it we puta massof birch, broomand heather branches and then withdrew to watch the birds from a distance. For some hours they worked feverishly on the nest adding further material until nightfall.

Within a few days the nest, which was not made of interlaced branches but was carefully heaped up, trampled and trodden, was finished. At its centre it had a shallow depression lined with heather and a sparrow’s old nest which the vultures had col- lected on the day of storm. While this period of nest building was going on, the birds were mating with much grunting and panting several times a day, generally on the nest, occasionally on branches in the enclosure but never on the ground.

The female did not leave the nest during the three days prior to laying and, one morning in February 1963, I had difficulty in making her move enough to allow me to see a single egg. From then on the nest was disturbed as little as possible.

The male and female shared the incubation in a rather irregular fashion; in general the female sat on the egg throughout the night, the male only relieving her in the morning. The female came down to drink, and rarely to bathe. Then, perched in the centre of the enclosure, she performed a long toilet, preening her plumage carefully. The birds left the egg completely at the end of the afternoon at feeding time, after which the female resumed her place on the nest.

The birds left the egg for rather long periods but it eventually hatched on day 59, when a not

22 B I R D S O F P R E Y IN C A P T I V I T Y

very vigorous chick hatched. The parents looked at it with surprise and almost without interest. Apparently they did not know how to feed it and it died on the second day.

In early spring 1964 the birds were actively occupied in repairing the nest with material we had placed on the ground in the middle of the enclosure. This time the parents incubated it more conscientiously and the chick hatched after j7 days. It was fed by the parents who regurgitated meat for it, and we hoped for success. Unfortun- ately, there were some vicious beak duels between the parents and the Imperial eagles, which wanted to capture the nest site. Trampled and grazed, the young vulture, which had already grown visibly, died at the age of six days.

In 1965 the egg was somehow broken, and in 1966 it was addled. The birds mated immediately after each of these setbacks, but there was no replacement laying in these rather unprolific large birds of prey.

In 1967 the pair, by now very experienced, repaired the nest at the end of the winter. The egg was laid on z March and the parents, takin, 0' turns to incubate, practically never left it alone. During the whole of the incubation period, which lasted 53 days, the birds continued to add materials to the nest, particularly green foliage which we provided for them. The egg hatched on 24 April 1967 and the chick was fed by its parents.

Aith infinite precautions, we were able to photograph the female and chick, and later the young one alone, quite regularly, but we always avoided handling it. After each occasion the furious parents, with plumage bristling, accom- panied us to the edge of their territory. Then, without delay, they returned to look after their young one.

Every day, in addition to the meat, we placed a freshly killed and opened guinea-pig on the edge of nest. The parent birds then tore up the carcase before distributing pieces to the chick. By three weeks of age the young one had reached the sizc of a duck, but it was still downy without a single feather.

On 20 June, at an age of almost tw-o months, the young one, standing on the nest and already very well fledged, started to beat its wings. A month later, on 20 July, fearing that it would suddenly leave the nest and perhaps also the enclosure containing the pinioned birds, I wrapped it in a

blanket and carried it to the back quarters, in order also to be able to feed it more easily than in the presence of its parents and the public.

At the age of 34 months, it was a magnificent bird, reddish-brown in colour, with the long un- ravelled collar of young vultures. It had now been feeding itself for some time. I t was very tame and allowed itself to be touched, scratched and stroked. I had no difficulty in weighing and measur- ing it; its span was 2.50 m (8.2 ft) and its weight 8 kg (17.6 lb).

The youngster rejoined the numerous birds of prey in the large aviary, without incident. At four months it perched like an adult and flew admirably. It may be noted that, after the removal of the young one, the parents did not seem in any way disturbed nor did they search for their offspring.

In 1968, after an incubation period of 55 days, the same pair again began to rear a new chick. By then exceptionally confident, they had already allo\Ted me to photograph and weigh the egg 240 g (8.5 oz), and they now found it quite natural to see me climb to the nest, touch the chick, photo- graph it - even with flash - and weigh it every week.

For example, on 27 April 1968, we took succes- si\e photographs of the hatching. We weighed it for the first time when it was two days old on 29 April and it turned the scales at 180 g (6.3 02).

By 9 May, when 12 days old, it weighed 720 g (25 oz). On this occasion the chick started to protest and even to vomit when I placed it on the pan of the balance. By 19 May, when 22 days old, it weighed 2.18 kg (4.5 lb) and on 25 May, when 28 days old, it weighed 3.10 kg (6.8 lb).

On 10 August, when it was 34 months old, the young one descended to join the adults and feed on a carcase. Then, being replete, it perched on a stump in the centre of the park instead of return- ing to the nest. Fearing that it might escape I caught it and took it directly to the large aviary where it vomited everything that it had swallowed.

On the following day it was perching together with the others. As in the previous year, the parents did not attempt to intervene, presumably because the time of removal of the youngster corresponded to the time when, in nature, it

ould normally have left the nest. In early spring 1969 the pattern was repeated

with the repair of the nest, parades, mating, laying, incubation and, on 13 April, after only 54 days of incubation, another chick was hatched.

1, 2 above. Male Steller's sea eagle Haliaeetus 1 pelagicus in immature plumage at the age of three years in August 1961 (1 ) and in adult plumage at the age of 11 years (2) at East Berlin Zoo (see page 19). The female sea eagle with which this bird formed a pair laid a single egg on 26 April 1963 which was unfortunately broken. However, breeding behaviour was shown by the pair each year from 1960 up to the female's death in June 1966. Gerhard Budich

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3. The Birds of Prey aviaries at Berne Zoo are constructed of metal and each is fitted with a cast Eternit nest box (see page 30). In this type of aviary the zoo has been successful in breeding kestrels Falco tinnunculus in 1967, 1968 and 1969. W. Nydegger

4, 5 left. Griffon vultures Gyps fulvus have bred at La Flhche Zoo in 1963,1964,1967 and 1968 (see page 21). Photograph 4 shows the female with the nest containing a single egg in 1968 and photograph 5 shows the parent bird with a 25 day old chick, which was the first reared successfully at La Flhche. When this fledgling was 34 months old its wing span was 2.5 m (8.2 ft) and it weighed 8 kg (17.6 Ib). Jacques Bouillault

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6-8. Magellan eagle owl Bubo virginianus nacurutu adult and chick (6). Spotted eagle owl B. a. africanus parent and chick (7) and Kenya eagle owl B. capensis mackinderi parent and chicks (8) were successfully bred at London Zoo in 1968 (see page 31). They are accommodated in aviaries about 2.25 m (7 ft) in height and are fed largely on freshly-killed mice but rats, day-old chicks and pieces of rabbit or raw lean meat are given as alternative diets. The Zoological Society of London

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9 overpage. Javan fishing owl Ketupu ketupa in San Diego Zoo. This owl was imported on 3 May 1933 and has been exhibited for 36 years. San Diego Zoo

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10 below left. White Little owls Athene noctoa at Jerez Zoo were found in Andalusia (see page 33). They are about 21 cm (8.25 in) in height. There is a complete lack of pigment in their feathers and the skin is a pinkish colour. Irides are lemon yellow and the pupils vary from red to black depending on the angle of the incident light. F. Carabantes

11 below right. Young Elf owl Micrathene whitnevi was hatched at Washington NZP about 4 April 1967 (see page 33). It was then approximately 1.25 cm (0.5 in) in length. The incubation period was about 21 days. It was first observed to leave the nest on 7 May by which time it was indistinguishable from the parents except that the plumage appeared softer and the facial pattern was less pronounced. Constance Warner

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B I R D S OF PREY I N C A P T I V I T Y 23

However this was a difficult hatching and I had to help the chick to break free. It was chilled and a little blood-stained as the mother had not re- turned immediately to warm and dry it. However, at the end of a week it looked very well and there appeared to be no more problems for us when, following some disturbance caused by urgent work in the area, the mother suddenly left the nest at the end of the morning. By the evening the chick was inert and chilled. I hastily collected it, put it in a warm place and fed it on the following day, but it died six days later at an age of 13 days.

In 1968 a second pair formed in the large aviary. The young female laid her egg on the ground and we had to place it in the nest. The male then took over the incubation and remained on the nest for two weeks, without eating or drinking. The female then replaced him, as though she were accustomed to do so, at the end of the morning. The male went directly to the pool for a long drink and then bathed until soaked. However, as soon as he was

dry he went back up into the big tree and relieved the female on the nest.

Up to the 56th day the female came from time to time to relieve the male, but then suddenly the birds seemed to lose interest in the egg and nest. Upon inspection it was found that the egg was addled. The birds mated on the nest on the same day, and subsequently mating was repeated from October 1968 until April 1969, but no egg laying resulted.

For interest the original pair of parent vultures were measured and weighed on 13 May 1969. The results were; Male: weight, 10 kg (zz lb); total length (tip of beak to tip of tail), 1.06 m (3.5 ft); span, 2.67 m (8-75 ft). Female: Weight, 10

kg (22 Ib); total length, 1.07 m (3.5 ft); span, 2.68 m (8.75 ft).

The span of the wing-clipped birds was calcu- lated by doubling the exact length between the centre of the back and the tip of the intact wing when extended.

A note on the breeding of Harris’ hawks Parabuteo unicinctus

at Los Angeles Zoo K . B. G A L E 1 & J A M E S W H I T E 2

‘L Falconer, Los Angeles Zoo, California, USA Assistant Director, Los Angeles Zoo, California, USA

In 1964 several fledgeling Harris’ hawks Para- buteo unzcinctus were imported into California from Mexico under permit from the California Department of Fish and Game. For the first year oftheir residence, they were maintained unsuccess- fully by their original owners as falcons.

In 1965 one pair from the original group was selected for breeding. Harris’ hawks are reported to be aggressive to one another and so at first the t\x o birds were maintained separately. When they wcre brought together they made serious attempts to attack each other and it required several months before they were successfully settled in a 4 x 4 x 4 5 m ( I Z x 12 x 14 ft) outdoor enclosure. Three and a half sides and a portion of the roof of this enclosure are wood, the remainder is wire mesh approximate- ly 5 cm (2 in) in diameter. The floor is soil. A rectangular pan, 60 x 30 cm (2 x I ft) in size,

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provides drinking water and bathing facilities. Across the rear of the cage 1.8 m (6 ft) above the ground there is a wooden ledge 1.2 m (4 ft) wide.

During 1966, their first year together, the birds showed no signs of breeding. The following year two nests of the Red-tailed hawk Bureo jainaicensis were placed on the wooden ledge but, although occasional attempts at mating were observed and the birds tore the nests apart, no- thing came of this activity and within two weeks it had ceased.

In 1967 several raven’s nests were placed on the wooden ledge; both birds tore the nests apart and used portions to build a crude platform on a forked limb near the front of the cage. Their efforts were not totally successful and James White assisted many times in making the platform more secure and in forming the nest. The birds mated