scispace - formally typeset
Search or ask a question

Showing papers in "Ostrich in 1996"


Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: Whittington et al. as mentioned in this paper investigated the establishment, growth and conservation of a mainland colony of jackass Penguins Spheniscus demersus at Stony Point, Betty's Bay, South Africa.
Abstract: Summary Whittington, P.A., Hofmeyr, J.H. & Cooper, J. 1996. Establishment, growth and conservation of a mainland colony of Jackass Penguins Spheniscus demersus at Stony Point, Betty's Bay, South Africa. Ostrich 67: 144–150. Following the discovery of a single pair of Jackass Penguins Spheniscus demersus nesting on the mainland at Stony Point, Western Cape Province, South Africa (34 22S 18 53E) in 1982, a colony developed and has since been regularly monitored. Numbers of nests increased to 35 in 1986, until a leopard Panthera pardus severely reduced the size of the colony. Numbers subsequently rose again to a total of 139 nests in 1990, but fell to 57 in 1993. This decrease was probably due to predation by mammals. Following the use of a trap and translocation of the animals caught, the colony increased again in 1995 and 1996. Productivity of the colony was insufficient for it to be self-sustaining, and it therefore presently represents a population sink.

31 citations


Journal ArticleDOI
01 Mar 1996-Ostrich
TL;DR: Kempe et al. as discussed by the authors investigated 56 active and 18 potential nest sites of the Southern Ground Hornbill Bucorvus leadbeateri in the Kruger National Park, South Africa over 298 nest-seasons during 1967-95.
Abstract: Summary Kemp, A. C. & Begg, K. S. 1996. Nest sites of the Southern Ground Hornbill Bucorvus leadbeateri in the Kruger National Park, South Africa, and conservation implications. Ostrich 67: 9–14. Details of 56 active and 18 potential nest sites of the Southern Ground Hornbill Bucorvus leadbeateri were recorded in the Kruger National Park, South Africa, over 298 nest-seasons during 1967–95. Nests were natural cavities with a median diameter of about 40 cm, 96% situated in 12 species of trees and 4% in rock faces. Only four species of tree provided 72% of nest sites and 85% of active nest sites were formed by rotting of a damaged branch or trunk. No habitat preference associated with nest sites was detected, but 61% of nests were within 400 m of a tourist road, possibly due to lower predation pressure. Nest attractiveness was correlated positively with nest height, cavity shallowness and proximity to tourist roads, but nest success was not correlated with any measured features of the sites. Average cavity d...

21 citations


Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: The impacts of human settlement, introduced brown rats Rattus norvegicus, local extinction of the Greater Frigatebird and other factors are discussed to explain changes in population sizes.
Abstract: Summary Le Corre, M. 1996. The breeding seabirds of Tromelin Island (western Indian Ocean): population sizes, trends and breeding phenology. Ostrich 67: 155–159. Formerly six or eight species of seabirds bred on Tromelin Island, but currently only two species do so: The Redfooted Booby Sula sula and the Masked Booby S. dactylatra. The last two species which became locally extinct, the Lesser Frigatebird Fregata ariel and the Greater Frigatebird F. minor, probably stopped breeding on the island as a consequence of human disturbance to breeding colonies. The populations of the two species of booby have opposing trends since 1954. The Masked Booby's population increased from 60 pairs in 1954 to 200–250 pairs in 1996 while the Red-footed Booby's population decreased from 500 pairs in 1968 to 130–180 pairs in 1996. The impacts of human settlement, introduced brown rats Rattus norvegicus, local extinction of the Greater Frigatebird and other factors are discussed to explain these changes in population sizes. Ne...

16 citations


Journal ArticleDOI
01 Mar 1996-Ostrich
TL;DR: The foraging behaviour of Crab Plovers is directly analogous to the ‘walk-stop-search-walk’ hunting behaviour of true plovers, and changes slightly depending whether the birds are foraging on sand or in water: they are nonterritorial when foraging.
Abstract: Summary Hockey, P.A.R., Plagenyi, E.E., Turpie, J.K. & Phillips, T.E. 1996. Foraging behaviour of Crab Plovers Dromas ardeola at Mida Creek, Kenya. Ostrich 67:33-44. The foraging behaviour of Crab Plovers is directly analogous to the ‘walk-stop-search-walk’ hunting behaviour of true plovers, and changes slightly depending whether the birds are foraging on sand or in water: they are nonterritorial when foraging. Crabs dominate the diet, but other invertebrates and fish are also eaten. Foraging efficiency increases with age and adults and subadults are able to satisfy their daily energy requirements in a single tidal cycle. The population of Crab Plovers at Mida Creek was much larger in 1994 than in 1992, but in 1994 adults achieved much higher intake rates than in 1992, suggesting considerable year-to-year variation in the carrying capacity of Mida Creek for Crab Plovers. The world population of 43–50 000 birds breeds at very few colonies and the species is thus a potential conservation concern. Because of...

11 citations


Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: The species is apparently monogamous, with an egg-laying season extending from at least November to February, usual clutch and brood sizes of two to three, ability rapidly to lay repeat clutches in a new nest, and post-breeding complete moult.
Abstract: Summary Safford, R.J. 1996. Notes on the biology of the Mauritius Black Bulbul Hypsipetes olivaceus. Ostrich 67: 151–154. The Mauritius Black Bulbul Hypsipetes olivaceus is a threatened passerine endemic to Mauritius. Direct observations of food items indicate that it is an arboreal omnivore. Animal prey consists mostly of insects and native day-geckoes (Phelsuma spp.). A wide variety of native and exotic fruits is also taken. The species is apparently monogamous, with an egg-laying season extending from at least November to February, usual clutch and brood sizes of two to three, ability rapidly to lay repeat clutches in a new nest, and post-breeding complete moult. In these respects, its annual cycle resembles that of the other native Mauritian passerines. It occurs at very low population density compared to its Indian Ocean congeners; possible reasons for this are given.

10 citations


Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: Herholdt, JJ, Kemp, AC & Du Plessis, D 1996 Aspects of the breeding status and ecology of the Bateleur and Tawny Eagle in the Kalahari Gemsbok National Park Ostrich 67:126-137 The nesting s
Abstract: Herholdt, JJ, Kemp, AC & Du Plessis, D 1996 Aspects of the breeding status and ecology of the Bateleur and Tawny Eagle in the Kalahari Gemsbok National Park Ostrich 67:126-137 The nesting s

10 citations


Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: Parker as discussed by the authors modelled the distribution of bird species in Swaziland in relation to environmental variables, and used logistic regression was used to model the observed distribution, but the results were limited.
Abstract: Parker, V. 1996. Modelling the distribution of bird species in Swaziland in relation to environmental variables. Ostrich 67: 105–110. Logistic regression was used to model the observed distribution...

8 citations


Journal ArticleDOI
25 Feb 1996-Ostrich
TL;DR: The Mauritius Cuckoo-shrike Coracina typica, a threatened passerine endemic to Mauritius, was studied between 1989 and 1993 and appeared to be sedentary, territorial and monogamous.
Abstract: Summary Safford, R. J. & Beaumont, J. 1996. Observations on the biology of the Mauritius Cuckoo-shrike Coracina typica Ostrich 67:15-22. The Mauritius Cuckoo-shrike Coracina typica, a threatened passerine endemic to Mauritius, was studied between 1989 and 1993. Previously undocumented immature plumages are elucidated. From observation of 364 food items, the diet was found to be mainly large, arboreal arthropods (81–90%) and day-geckoes (10%), with 9% of items unidentified but possibly arthropods. Geckoes, the largest items, formed more than 10% of the total biomass eaten. Individuals varied in the items selected. The species appeared to be sedentary, territorial and monogamous. Egg-laying occurred from September to February, with a complete post-breeding moult. Both sexes built the nest, incubated and fed the young. From laying to fledging took around 50 days, with a further three-month dependency period; such protracted development is typical of the family. The diet and foraging methods may in part expla...

7 citations


Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: Comparisons of the vocalizations and social behaviour of southern African Pycnonotus bulbuls showed that P. barbatus and P. capensis are easily distinguished, whereas the song characteristics of P. nigricans overlap those of both the other species.
Abstract: Summary Lloyd, P., Hulley, P.E. & Craig, A.J.F.K. 1996. Comparisons of the vocalizations and social behaviour of southern African Pycnonotus bulbuls. Ostrich 67: 118–125. Vocalizations and associated behaviour of three Pycnonotus species are described, based on field observations and tape recordings from which sonagrams were produced. These species, which are locally sym-patric and hybridize, have similar vocalizations and displays; differences are most apparent in their contact calls and songs. Quantitative analysis of the songs showed that P. barbatus and P. capensis are easily distinguished, whereas the song characteristics of P. nigricans overlap those of both the other species. Playback experiments with territorial male P. barbatus in an area of allopatry showed similar responses to songs of conspecifics and of P. nigricans, but almost no response to the song of P. capensis.

7 citations


Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: Food of Sacred Ibis Threskiornis aethiopicus nestlings in the Free State province, South Africa showed marked differences in nestling food between two breeding seasons at the same site and the proportion of larvae of Calliphoridae, pupae and larvae of Sphingidae and frogs was higher in pellets than in stomachs collected during the same breeding season from the same sites.
Abstract: Summary Kopij, G., Kok, O. B. & Z. N. Roos 1996 Food of Sacred Ibis Threskiornis aethiopicus nestlings in the Free State province, South Africa. Ostrich. 67:138-143. A total of 88 regurgitated pellets and 47 stomachs collected from Sacred Ibis chicks was analysed. The bulk of the food consisted of frogs (mainly Rana angolensis and Xenopus laevis), crabs Potamon warreni, larvae of Calliphoridae and Sphingidae and imagos of Coleoptera. Such inorganic materials as gravel, pieces of glass and plastic were also recorded. Analyses of stomach contents showed that during the first 10 days of life the nestlings fed mainly on crabs and the imagos of Coleoptera and later mainly on the larvae of Sphingidae and imagos of Coleoptera. There were marked differences in nestling food between two breeding seasons at the same site. The proportion of larvae of Calliphoridae, pupae and larvae of Sphingidae and frogs was higher in pellets than in stomachs collected during the same breeding season from the same site.

7 citations


Journal ArticleDOI
01 Nov 1996-Ostrich
TL;DR: For example, at Langebaan Lagoon, South Africa, the seasonal use of sandflats and saltmarshes by waders at low and high tide was studied in this article.
Abstract: Summary Summers, R.W. & Kaletja-Summers, B. 1996. Seasonal use of sandflats and saltmarshes by waders at low and high tide at Langebaan Lagoon, South Africa. Ostrich 67:72-79. Migrant and resident waders were counted on sandflats and saltmarshes at low and high tide during two summers (197576 and 1976–77) and two winters (1975 and 1976) at Langebaan Lagoon. Intertidal sandflats supported higher densities of waders than saltmarshes at low tide in summer (18.7 and 17.2 waders ha' on sandflats compared with 0.4 and 2.9 waders ha' on saltmarshes) and winter (0.9 and 3.1 compared with 0.6 and 1.9 waders ha I for the two years). At high tide, most waders moved onto saltmarshes, attaining densities of 70.4 and 53.6 waders ha' in the two summers, and 5.7 and 15.6 birds ha' in the two winters. Resident waders comprised 0.3 and 0.8% of the wader community in the two summers and 41 and 5% in the two winters. They were also at higher densities in winter than in summer. The composition of wader communities on the diff...

Journal ArticleDOI
01 Mar 1996-Ostrich
TL;DR: Generalised linear models, with logit-link functions, were used to predict which relatively poorly-studied terrestrial South African bird species had at least equal odds of being either facultative cooperative breeder or regular cooperative breeders compared with non-cooperative breeders.
Abstract: Summary Armstrong, A.J. & Juritz, J. 1996. Prediction of cooperative breeding by terrestrial bird species in South Africa. Ostrich 67: 1–8. Cooperative breeding in birds may be difficult to detect without marking techniques, and the breeding biology of most bird species in South Africa has not been intensively studied. Prediction of cooperative breeding from ecological and life-history traits may be useful in that helping can be specifically looked for in species having a certain set of such traits. Generalised linear models, with logit-link functions, were used to predict which relatively poorly-studied terrestrial South African bird species had at least equal odds of being either facultative cooperative breeders or regular cooperative breeders compared with non-cooperative breeders. Hole-nesters in steppe habitat and species nesting on water were likely to be facultative cooperative breeders. Species which feed in permanent groups and have altricial young are likely to be regular cooperative breeders. S...

Journal ArticleDOI
01 Mar 1996-Ostrich
TL;DR: There was a distinct pattern of seasonal abundance, with birds being most numerous in the rainy season (November-April) and the relative abundance of some fish species also was greatest during this period.
Abstract: Summary Hustler, K. & Marshall, B.E. 1996. The abundance and food consumption of piscivorous birds on Lake Kariba, Zimbabwe-Zambia. Ostrich 67:23-32. About 40 species of piscivorous birds have been recorded on Lake Kariba (Zimbabwe-Zambia) but only 26 were observed during this study, carried out in 1986–87. The Reed Cormorant Phalacrocorax africanus was the most numerous and made up 51.4% of all the birds seen, followed by the Whitewinged Black Tern Chlidonias leucoptera (26.7%), and the Darter Anhinga melanogaster (10.8%). Several species roosted or bred in the drowned trees which project above the lake surface but gently sloping shores were the most important feeding grounds. Relatively few birds were seen on steeply sloping shores or in open water. There was a distinct pattern of seasonal abundance, with birds being most numerous in the rainy season (November-April). The relative abundance of some fish species also was greatest during this period. There was a positive relationship between the numbers o...

Journal ArticleDOI
01 Nov 1996-Ostrich
TL;DR: The non-breeding hunting behaviour of members of mixed flocks of Lesser Kestrels Falco naumanni and Eastern Redfooted Falcons Falco amurensis was studied during January 1991 in the Transvaal Province of South Africa, with perch-hunting more successful than hover-hunterting in both species.
Abstract: Summary Zank, C.M. & Kemp, A.C. 1996. A comparison of hunting behaviour by Lesser Kestrels Falco naumanni and Eastern Redfooted Falcons Falco amurensis in their non-breeding South African range. Ostrich 67: 63–66. The non-breeding hunting behaviour of members of mixed flocks of Lesser Kestrels Falco naumanni and Eastern Redfooted Falcons Falco amurensis was studied during January 1991 in the Transvaal Province of South Africa. Both species employed perch-hunting and hover-hunting to catch their insectivorous prey. Only 46.8% of Lesser Kestrel and 49.8% of Eastern Redfooted Falcon strikes were successful, with perch-hunting more successful than hover-hunting in both species (59% vs 39% and 59% vs 41% respectively). Hover-hunting resulted in a significantly higher strike rate (47 strikes.hr−1 vs 14 strikes.hr−1; 34 strikes.hr−1 vs 15.5 strikes.hr−1) and kill rate (18 kill.hr1 vs 9 kills.hr1; 14 kills.hr1 vs 9 kills.hr1) than perch-hunting for both species. Eastern Redfooted Falcons hovered for significantly...

Journal ArticleDOI
01 Dec 1996-Ostrich
TL;DR: Morphological dispersion of the introduced land-birds of Saint Helena and interspecific competition may influence the outcome of...
Abstract: Lockwood, J.L., Moulton, M.P. & Brooke, R.K. 1996. Morphological dispersion of the introduced land-birds of Saint Helena. Ostrich 67: 111–117. Interspecific competition may influence the outcome of...

Journal ArticleDOI
01 Nov 1996-Ostrich
TL;DR: Langrand et al. as mentioned in this paper provided information on the Andringitra Massif and the Isoky-Vohimena Forest populations of this species, as well as summarize other records outside previously known areas of its geographical range.
Abstract: Summary Langrand, O. & Goodman, S.M. 1996. Current distribution and status of Benson's Rockthrush Pseudocossyphus bensoni. a Madagascar endemic. Ostrich 67:49-54. Benson's Rockthrush Pseudocossyphus bensoni, described in 1971. was previously thought to have a limited range in central southwestern Madagascar centred around the lsalo Massif. Recent ornithological surveys of the high mountain zone of the Reserve Naturelle Integrale d'Andringitra, about 170 km east of the lsalo Massif and of the Isoky-Vohimena Forest, 60 km west of the lsalo Massif, found substantial populations of P bensoni inhabiting these areas. In this paper we provide information on the Andringitra Massif and the Isoky-Vohimena Forest populations of this species, as well as summarize other records outside previously known areas of its geographical range.

Journal ArticleDOI
01 Nov 1996-Ostrich
TL;DR: Post mortem examinations revealed multifocal necrosis in the liver and spleen and Hist, intranuclear inclusion bodies were present, particularly in cells at the periphery of necrotic foci.
Abstract: Summary Williams, M.C. & Nesbit, J.W. 1996. Fatal herpesvirus infection in a Cape Eagle Owl Bubo capensis and a Spotted Eagle Owl Bubo africanus. Ostrich 67:50-62 Fatal, systemic herpesvirus infection was reported in a Cape Eagle Owl Bubo capensis and a Spotted Eagle Owl Bubo africanus. This is believed to be the first report of systemic herpesvirus infections in owls in South Africa. Post mortem examinations revealed multifocal necrosis in the liver and spleen. Histologically, intranuclear inclusion bodies were present, particularly in cells at the periphery of necrotic foci. Typical herpesvirus virions, demonstrable by transmission electron microscopy, were present. Viral isolations were unfortunately not undertaken.

Journal ArticleDOI
01 Nov 1996-Ostrich
TL;DR: The Redbilled Hornbill Tockus erythrorhytzchus is not well known from a systematic and ethological point of view but a study in Senegal involved 80 hours of observation on the two main stages of nest-preparation : bringing of materials and partial sealing of the nest entrance.
Abstract: Diop, M.S. & Treca, B. 1996. Distribution of nest preparation tasks between mates of the Redbilled Hornbill Tockus erythrorhynchus. Ostrich 67: 55–59. The Redbilled Hornbill Tockus erythrorhynchus ...

Journal ArticleDOI
01 Nov 1996-Ostrich
TL;DR: Van Eeden et al. as mentioned in this paper found metal residues in the tissues and food of a juvenile Purple Heron, Ardea purpurea (Ardeidae), in an industrial area of Germiston on the East Rand of South Africa.
Abstract: Summary Van Eeden, P.H., Schwnbee, H.J. & Du Preu. H.H. 1996. Metal residues in tissues and food of a juvenile Purple Heron, Ardea purpurea (Ardeidae). Ostrich 67:67-71. Tissues as well as the stomach contents of an apparently sick, male, juvenile Purple Heron Ardea purpurea (477 g body weight) were analysed for 13 metals. The bird was caught in the industrial area of Germiston on the East Rand of Johannesburg. The gross pathological abnormalities observed in this heron were similar to those found in birds that died from exposure to acute concentrations of lead-containing compounds. The aluminium and lead residues were considered to be indicative of acute exposure whilst the concentration of cadmium was indicative of chronic exposure. Silver was not detected in all the samples analysed. Concentrations of cobalt, manganese and strontium were generally smaller than 100 pg/g dry mass whilst chromium, copper, nickel, zinc and antimony were smaller than 500 pg/g. Iron occurred in the highest concentrations in ...