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Journal ArticleDOI

Field Notes on certain Raptorials and Water‐Birds in Kenya Colony—Part II.*

28 Jun 2008-Ibis (Blackwell Publishing Ltd)-Vol. 3, Iss: 4, pp 617-643
About: This article is published in Ibis.The article was published on 2008-06-28. It has received 8 citations till now. The article focuses on the topics: Field (physics).
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Journal ArticleDOI
03 Apr 2008-Ibis
TL;DR: The fluctuations of population in an area of 146 square miles in Embu district, where a census of eagles was carried out in 1950, are described and discussed and the inter-relations of various species are discussed.
Abstract: Summary. 1 The present paper is supplementary to that in ‘Ibis’ 94 and 95. 2 The fluctuations of population in an area of 146 square miles in Embu district, where a census of eagles was carried out in 1950, are described and discussed fur 951–52. 3 The inter-relations of various species are discussed, particularly for Aquila wahlbergi and Lophaetus occipitalis. 4 General accounts of breeding biology are given for Sagittarius serpentarius, Aquila wahlbergi, Hieraaetus ayresi and Terathopius ecaudatus, and supplementary data for Aquila verreauxi, Hieraaetus spilogaster, Polemaetus bellicosus, Stephanoaetus coronatus, Lophaetus occipitalis, Circaetus cinereus and Circaetus pectoralis. These accounts are given under the following heads:— 1 General notes on adults. 2 Nests and nest-building. 3 The incubation period. 4 The fledging period: (a) general, (b) development of the young, (c) parental behaviour, (d) food. 5 The post-fledging period. 5 Special problems of breeding biology are discussed under the following heads: (1) Display; (2) Eagle-weaver-bird nesting-associations; (3) Feeding rates of female and eaglet; (4) Breeding seasons; (5) Breeding success and replacement rate.

29 citations

Journal ArticleDOI
01 Mar 1975-Ostrich
TL;DR: Observations extending over 12 years were made on two pairs of African Hawk-Eagles Hieraaetus spilogaster at Essexvale, Rhodesia, showing a progressive decline although both adults still perched in the nest tree a great deal.
Abstract: Summary Steyn, P. 1975. Observations on the African Hawk-Eagle. Ostrich 46:87-105. Observations extending over 12 years were made on two pairs of African Hawk-Eagles Hieraaetus spilogaster at Essexvale, Rhodesia. Details on various aspects of adult behaviour are given, particularly on hunting methods and calls. Nest repair usually took about 4–5 weeks. and limited observations indicated that the male does most of the work. Incubation is done mostly by the female, the male relieving her when he brings prey. The incubation period is 43 ± 1 day. Details are given of parental behaviour during the fedging period; time on the nest showed a progressive decline although both adults still perched in the. nest tree a great deal. The male provided most of the prey. The growth and behaviour of the eaglet Is described; usually the eaglet becomes a “brancher” before its first flight which, in four cases, occurred between 61–71 days. Post-of edping attachment to the nest lasted about three weeks in one case. Frief menti...

12 citations

Journal ArticleDOI
03 Apr 2008-Ibis
TL;DR: Breeding records in Tropical Africa show, when analysed with reference to egg-dates, that as a rule in each area the young get through their fledging period, or at least the later, unbrooded part, during the local cool dry season.
Abstract: Summary An account is given of one hundred hours of observations at a Bateleur'a nest in north-eastern Tanganyike Territory. The adults were a white-backed bird and a chestnut-backed, with a sub-adult; probably over three years old, in association with them. The youngster took 130 dap to fledge. During at least part of the time all its food was brought by the white-backed adult. When the fledgling was about one month old its feeds averaged about one in eight hours; during its last week in the nest feeds were nearly three times as frequent. Literature and unpublished data are reviewed in relation to special points of interest, viz.:— Slow development and maturation accords with longevity. Fledging period apparently longer than authentically recorded for any land bird. First wing-moult may have started before first flight. Tail length is greater in proportion to wing in juveniles than in adults. Proportion of white-becks to chestnut-backs differs in parts of Africa, being least in South africa. White-tailed birds seem confined to Sudanese semi-desert belt. Voice, flight habits and wing-noises seem to differ in parts of Africa. Food comprises both carrion and live prey, especially snakes, but not poultry or other birds. Claws are not less sharp than those of Stephanoaetus and Polemaetus. Breeding records in Tropical Africa show, when analysed with reference to egg-dates, that as a rule in each area the young get through their fledging period, or at least the later, unbrooded part, during the local cool dry season. Psychologically the Bateleur is most peculiar: in the wild it is shy of man, sociable with big birdv of its own and other species, and breeding birds tolerate sub-adults: in captivity it becomes unusually tame, has a grecting ceremony for friends and likes to be handled.

11 citations

Journal ArticleDOI
01 Sep 1980-Ostrich
TL;DR: Three nesting territories of Bateleurs Terathopius ecaudatus were studied at Essexvale, Zimbabwe, from 1962 to 1976, and this paper augments previously published observations.
Abstract: Summary Steyn, P. 1980. Breeding and food of the Bateleur in Zimbabwe (Rhodesia). Ostrich 51:168-178 Three nesting territories of Bateleurs Terathopius ecaudatus were studied at Essexvale, Zimbabwe, from 1962 to 1976, and this paper augments previously published observations. Further details of breeding biology are given, and these show close similarities to those of snake eagles Circaetus spp. In 22 pair-years at Essexvale 17 young were reared, or 0,77 young/pair/year, and if combined with five years' observation at another nest in Zimbabwe then the figure is 0,81. A total of 238 prey items was collected, 47,5% birds, 42,0% mammals, 8,0% reptiles and 2,5% fish, and comparisons are made with three other studies of Bateleur prey. Evidence for direct predation is considered; Bateleurs kill many species of birds and a variety of mammals, but reptiles are not a significant aspect of diet. Carrion appears to be most important in the diet of immatures. The Bateleur has undergone a serious decline in South Afric...

10 citations