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Peter Steyn

Bio: Peter Steyn is an academic researcher. The author has contributed to research in topics: Hieraaetus & Booted eagle. The author has an hindex of 8, co-authored 14 publications receiving 144 citations.

Papers
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Journal ArticleDOI
01 Mar 1973-Ostrich

35 citations

Journal ArticleDOI
01 Sep 1973-Ostrich
TL;DR: The cuckoo gains weight very rapidly, and it is suggested that this is because of its brighter gape and more intense gaping response which ensure that it is fed preferentially.
Abstract: Summary Steyn, P. 1973. Some notes on the breeding biology of the Striped Cuckoo. Ostrich 44: 163–169. Information is presented on the breeding biology of the Striped Cuckoo, a species for which little authentic material exists. A number of cases of parasitism of the Arrow-marked Babbler are given. Pre-laying behaviour is similar to that of the Jacobin Cuckoo. The blue egg of the cuckoo may be distinguished on several minor points, but mainly because it is rounder and broader than those of the host species. The growth and development of a nestling is outlined up to its ninth day when it was killed by a snake. It was reared to this stage with three babbler chicks, probably because several babblers contribute to feeding the nestlings. The cuckoo gains weight very rapidly, and it is suggested that this is because of its brighter gape and more intense gaping response which ensure that it is fed preferentially. Anti-predator devices such as open-gaped lunges, jerking movements of the body and the exudation of ...

19 citations

Journal ArticleDOI
01 Jun 1981-Ostrich
TL;DR: The Booted Eagle Hieraaetus pennatus is a breeding visitor to the Cape Province of South Africa, wintering mostly in Namibia on present knowledge, andPalaearctic birds probably also reach the Cape but arrive later.
Abstract: Summary Steyn, P. & Grobler, J. H. 1981. Breeding biology of the Booted Eagle in South Africa. Ostrich 52:108-118. The Booted Eagle Hieraaetus pennatus is a breeding visitor to the Cape Province of South Africa, wintering mostly in Namibia on present knowledge. Palaearctic birds probably also reach the Cape but arrive later. Two nests in different localities in the Cape were studied. The birds breed soon after arrival. Both sexes build the nest on a cliff ledge. Incubation, which lasts 40 days, is done mostly by the female. The female spends most of her time on the nest during the first four weeks of the nestling period, but considerably less time thereafter. The male provides nearly all the prey until near the end of the nestling period, and helps to feed the young. Details of nestling growth and behaviour and of parental care are given. The nestling period was 50 and 54 days in two cases. Post-nestling dependence is about two months. Prey preferences in the two study areas were very similar: 54% birds, ...

13 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


Cited by
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Journal ArticleDOI
TL;DR: This investigation revealed the presence of three species of Acanthocephala (Neoechinorhynchus pseudemydis, N. emyditoides, and N. chrysemydis) in Louisiana turtles and confirms Fisher’s (1960) work.
Abstract: Prior to the work of Cable and Hopp (J. Parasit. 40(6): 674.680, 1954) Neoechinorhynchus emydis (L e i d y, 1851) was the only recognized species of Acanthocephala in North American turtles. To date, a total of five species have been described. Of these, two species (Neoechinorbynchus pseudemydis Cable and Hopp, 1954, and N. emyditoides Fisher, 1960) were recovered from six of 12 Louisiana turtles (Pseudemys scripta elegans (Wied)) examined by Fisher (J. Parasit. 46(2): 257-266, 1960). He (1960) also found N. chrysemydis Cable and Hopp, 1954 in Pseudemys scripta subsp. The data pt .sented are results of studies conducted between the spring of 1965 and the summer of 1966. Seventynine turtles (48 female and 31 males) encompassing seven species (47 Pseudemys scripta elegans (Wied), three P. floridana hoyi (Holbrook), eight Chelydra serpentina serpentina (L.), eight Kinosternon subrubrum hippocrepis Gray, seven Terrapene carolina carolina (L.), five T. c. triunguis (Agassiz) and one Trionyx muticus (LeSueur) collected from Baton Rouge and vicinity were examined. This investigation revealed the presence of three species of Acanthocephala (Neoechinorhynchus pseudemydis, N. emyditoides, and N. chrysemydis) in Louisiana turtles and confirms Fisher’s (1960) work. Of the seven species of turtles examined, only P. s. e!egans (25 16 females and 9 males) and P. floridana hoyi (2 females) were positive with infection. Three of the 25 P. s. e!egans had mixed infection comprising three species of Neoechinorhynchus while seven had two species respectively. P. f!oridana hoyi represents a host record for N. chrysemydis;

790 citations

Journal ArticleDOI
TL;DR: Counterparts of the cuckoos are known among insects, of which several groups are specialized for interactions with social insects, ranging from facultative commensalism to an inquilinism close to the cucksoo nexus.
Abstract: Birds as brood parasites lay their eggs in the nests of other kinds of birds; these "hosts" incubate and rear the young. In the Old World, cuckoos have long been known as brood parasites. The early Vedic writers of India as well as Aristotle mentioned as common knowledge the fact that cuckoos are reared by other species (42). About 1 % of all bird species are brood parasites, including the honey guides (Indicatoridae), nearly half of the 1 30 species of cuckoos (Cuculidae), two genera of finches (Vidua and Anomalospiza, Ploceidae), five cowbirds (Icteridae), and a duck (Heteronetta atricapilla, Anatidae) (37-42, 9 1-93, 1 14, 1 32, 1 36, 199). No other vertebrate groups with parental care so consistently parasitize other species. [A few freshwater fish do occasionally ( 14).] Counterparts of the cuckoos are known among insects, of which several groups are specialized for interactions with social insects, ranging from facultative commensalism to an inquilinism close to the cuckoo nexus. Some adult insects as well as immature depend completely on their hosts (4, 202). Most parasitic birds are altricial; their nestlings depend on the host for food. The parasitic duck, however, obtains only protection and warmth from the host and feeds and cares for itself shortly after hatching ( 199).

495 citations

Book
01 Jan 1997
TL;DR: In this paper, a major work covering the breeding and non-breeding birds of the Southern African sub-region is presented, which sets new standards in its scope and in its methods, for setting a measured baseline against which to judge environmental trends across the great range of southern Africa.
Abstract: This is a major work covering the breeding and non-breeding birds of the Southern African sub-region. Published in two volumes, Volume One includes introductory chapters describing methodology and the 'avi'-geography of the region, with habitat photos, and coverage of the non-passerines, whilst Volume Two covers the passerines. Some 900 species are covered in total, including 200 vagrants, with detailed species accounts, maps and statistics for at least 500 species. Conservation issues are discussed for most species. '...sets new standards in its scope and in its methods...it will come to be valued ever more as years go by, for setting a measured baseline against which to judge environmental trends across the great range of southern Africa.' - Colin Bibby, "BirdLife International".

347 citations

Journal ArticleDOI
TL;DR: The first assemblage-level global examination of 'Bergmann's rule' within an entire animal class suggests that global patterns of body size in avian assemblages are driven by interactions between the physiological demands of the environment, resource availability, species richness and taxonomic turnover among lineages.
Abstract: In 1847, Karl Bergmann proposed that temperature gradients are the key to understanding geographic variation in the body sizes of warm-blooded animals. Yet both the geographic patterns of body-size variation and their underlying mechanisms remain controversial. Here, we conduct the first assemblage-level global examination of 'Bergmann's rule' within an entire animal class. We generate global maps of avian body size and demonstrate a general pattern of larger body sizes at high latitudes, conforming to Bergmann's rule. We also show, however, that median body size within assemblages is systematically large on islands and small in species-rich areas. Similarly, while spatial models show that temperature is the single strongest environmental correlate of body size, there are secondary correlations with resource availability and a strong pattern of decreasing body size with increasing species richness. Finally, our results suggest that geographic patterns of body size are caused both by adaptation within lineages, as invoked by Bergmann, and by taxonomic turnover among lineages. Taken together, these results indicate that while Bergmann's prediction based on physiological scaling is remarkably accurate, it is far from the full picture. Global patterns of body size in avian assemblages are driven by interactions between the physiological demands of the environment, resource availability, species richness and taxonomic turnover among lineages.

260 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared trends between the ungulate migration and non-migration season among three land use types (reserve, buffer, and grazed) and among the species surveyed to establish the causes of declines in scavenging raptors.

158 citations