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Dr. Llewellyn Grimes 《Ostrich》2013,84(3-4):125-128
Ward, D. 1990. The demography, diet and reproductive success of African Black Oystercatchers on a sandy beach. Ostrich 61:125-133. The biology of African Black Oystercatchers Haematopus moquini on a sandy beach is described and compared with earlier studies of this species on mixed and rocky shores. Adult oystercatchers specialized on the wedge clam Donax serra. There was no difference in the size of clams taken by adult and immature oystercatchers, although chicks were fed smaller clams. The abundance of oystercatchers and the biomass of Donax serra was positively correlated. There was no significant relationship between clutch size, egg volume or clutch volume and prey biomass. 相似文献
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P. K. Tubbs 《Ostrich》2013,84(2):127-128
Saurola, P. 1994. African non-breeding areas of Fennoscandian Ospreys Pandion haliaetus: a ring recovery analysis. Ostrich 65:127-136. More than 36 000 Ospreys have been ringed in Fennoscandia up to 1992 and 638 of these have been reported from 30 different African countries. The recoveries suggest that adult and first-year Ospreys arrive in Northern Africa from earl September and cross the Sahara in late September to October. A record bird migrated 9817 km from Finland to South Africa in less than 40 days, at an average speed of more than 245 km/day. The majority of all age classes of Fennoscandian Ospreys spend December to February in equatorial Africa. The average compass heading from the different parts of the Fennoscandian breeding areas to the sub-Saharan non-breeding areas is roughly the same, ca. 206°. The longitude of the non-breeding area is dependent on the longitude of the breeding area. Western subpopulations spend their non-breeding period further to the west than more eastern subpopulations but there is much overlap. Ospreys are still heavily persecuted in many African countries. 相似文献
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D. W. Snow 《Ostrich》2013,84(1):87-88
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 mention is made on the development of adult plumage. Birds made up 74%. mammals 25% and reptiles 1% of 104 prey items recorded at Essexvale. Gamebirds are preferred. The two nests had completely different breeding histories. One pair reared no young while the replacement rate of the other pair was 0,83 voung/pair/year. The combined replacement rate of the two pairs was 0,48 young/pair/year. There appear to be no records of two eaglets being reared together in southern Africa. 相似文献