I20 B R E E D I N G

The was first seen entering the nest site on 14 October. It was interesting to note that he could barely squeeze in whereas the 9 entered without diEidty. Unlike the previous nesting, the nest site was vigorously defended. In addition to defending the nest territory, the 8 was frequently observed chasing birds anywhere near him regardless of his location. Long-wattled umbrella birds Cephalopterus penduliger, turacos Tauram leucotis and chachalacas Ortafis erythroptera were frequent victims. The 9 was not as defensive. The eggs were laid on or about 29 October. The Q assumed most of the incubation duties. The young apparently hatched on 13 November. At that time, the 9 was observed outside the nest with a portion of an eggshell which she ultimately consumed. On 14 November the young were apparently eaten by the adults and the nesting attempt was temporarily abandoned. Activity started again on 18 November but did not commence in earnest until the first week of January 1971. The nest site was the same as the previous attempt but was further altered as shown on Fig. I. Table I is a chronological record taken from Thompson's notes.

A fourth attempt was noted on 18 March 1971 when the birds were observed copulating next to the same nest site. Excavation continued until I4 April. The first egg was laid on 16 April but had disappeared by the x s t . Four additional eggs were noted in the nest on 30 April. OR 1 5 May both adults were observed out of the nest and four young were observed in the hole. The 6 was much more involved in the incubation process than previously noted. In addition to the food items already mentioned, the adults were also observed bringing the newly-formed fruit

from the Ficus tree and snails to the nest. The snails were cracked and the shell fragments apparently removed by the 9 prior to feeding. Between 27 June and 4 July the young departed the nest having spent 43 to 47 days in the cavity. Three were captured for hand-rearing and one was left with the adults. It was interesting to note that the three hand-reared individuals were sigdcantly Iighter than the toucanet left with the adults. The heaviest of the three hand-reared birds one month after leaving the nest weighed 170 g, whereas the young with the adults weighed 174 g. Presumably, this was the last to hatch and therefore should have been lighter. This may have been due to the adults feeding the young more frequently. Thirty-two days after the previous clutch left the nest, four more eggs wcrc laid on 25 July. These hatched on 10 August.

By August I972,21 young had been reared and thc incubation period definitely established as 16.5 days. Three pairs are at present actively engaged in nesting, with the first second genera- tion birds due within a month. Thc bill of the Z is significantly shorter than the 8 and it appears that the chestnut rump of the 0 is lighter than that of the $. In later nesting attempts the 68 were actively engaged in the excavation proccss.

R E F E R E K C E S

I. BREHM,W.W. (1969) :Breeding the Green-billed toucan Rnniyhnsfos dicdorus at the Walsrode Bird Park. l i t t . ZM

2. PETERS, J. L. (1944): Check list of birds of the rr~orid. 6. Cambridge: Harvard University Press. 3 . SKUTCH, A. F. (1944) : Life history of the blue-throated toucaner. Wilson B i d . 50: 133-151.

yb. 9 : 134-135.

Manuscript submitted 15 November 1971

Hatching the White-necked bald crow Picathaites gymnocephabrs

at Amsterdam Zoo D. DEKKER Bielogist, Matirra Artis Magistra, Atnstcrdatn, A-crhrlatids

Since 1967 Amsterdam Zoo has exhibited three White-necked bald crows Picathartes gymno- c~pha2ms, housed in the Bird House in an open- faced aviq-. Thcy spend most of the day within

the public area and behave quite freely towards visitors and zoo keepers. The temperature is kept constant at 18-2ooc.

At the end of their first six months they attcnip-

B R r E D I N G 17.1

DATE HATCHED REMARKS

1968 18 August 1970 8 August 1971 26 March

31 March I June

I o July 14 August 24 September 3 1 December

I young - died 19 August I young - died I September I young - died 4 April I young - died 10 April z young - died 5 June z young - died 14 July z young - died I 5 and zz August 2 young - alive z young - alive

Table I. White-necked bald crows Picatkarfes gyriimtephalus hatched at Amsterdam Zoo in 1968-71.

ted to build a nest, examiningmanyperpendicular walls for suitability, most with disappointing results because the ‘mortar’ used did not adhere. The artificial nests and fixed pieces of stone gauze offered to them were refused.

A greater variety of building material was offered. It turned out that the birds preferred a mixture of black earth and clay. They also used material with a fibrous structure like coconut fibre, palm fibre and peat moss Sphagnum Both materials (earth and fibre) were mixed by the birds themselves and brought to the nesting site in the form of little balls. At last they succeeded in building a cup-like nest on top of a wall- lamp.

Brooding began for the first time in August 1968. Both 6 and 9 took part, relieving each other at least six times a day. The incoming bird brought nesting material with it and as a result the rim of the nest grew higher and higher. When approachmg the nest both birds used a futed route, moving in leaps and bounds.

One chick was hatched on 18 August, but the next day it was found dead on the floor under the nest, with severe internal bruising.

In 1969 a new nest was built a t a height of about 4 m, right opposite the first one, and with- out a point of support. No breeding activity was noticed.

In 1970 one of the three birds was apparently ostracised; for safety’s sake we separated this bird and placed it in a closed aviary. The 1968 pattern was repeated - incubation in August

but the one chick which hatched living only a few days.

The following year eggs were incubated in March, June, July and August. In all four cases two young were hatched but they died within a period of four-ten days after hatching. The average incubation time was 23 days. Post- mortem findings were lack of vitamin A and a disturbed kidney function. When on 24 Septem- ber two young were again hatched, we added a concentrated vitamin A preparation to the parents’ food (Davitamon-A-Forte (Organon) : 6 drops - 10,000 i.u. vitamin A per day), plus an antibiotic (Aureomycin). The young grew up without M i d t y .

Their (protein-rich) diet consisted of: ground meat; chopped smelt; oneday-old mice; cock- roaches; and Camicon (a vitamin-mineral mixture, especially used for carnivorous animals). In feeding the young, the parents showed a preference for cockroaches and smelt. During the first week they removed the faeces of the young from the nest, and thereafter we found the faeces on the floor directly under the nest.

At the age of two weeks the heads of the young were clearly visible above the rim of the nest. Both left the nest at an age of four weeks. Except for the short tail they closely resembled their parents. The yellow on the head was a bit paler, the beak perhaps a little shorter. About two weeks after leaving the nest the young were able to eat independently.

At the beginning of December the adult birds again took possession of the nest, without taking further care of the young. Very soon they were again incubating and on 31 December two young were hatched. These were reared without difficulty and on the same diet as men- tioned above. To the time of writing (April 1972), the six Picuthurtes are living happily together in the open-faced aviary.

PRODUCTS MENTIONED IN THE TEXT Davitamon-A-Forte (Organon): a vitamin A con- centrate manufactured by N. V. Organon. Oss. Carnicon: a vitamin-mineral mixture manufactured by Trouw, Putten.

Manuscript submitted z May I972