Showing papers in "Ostrich in 1992"
TL;DR: It is concluded that it is rare in free-living Jackass Penguins in their natural habitat and problems of prophylaxis in captive populations are discussed.
Abstract: Summary Brossy, J-J 1992 Malaria in wild and captive Jackass Penguins Spheniscus demersus along the southern African coast Ostrich 63: 10–12 Avian malaria has been commonly reported in surveys of penguins of the genus Spheniscus, particular1 from American zoos We have found similar infections in about 15% of penguins being kept at SANC-COB (South African Foundation for the Conservation of Coastal Birds) However we found only one doubtful positive identification of Plasmodium relictum in samples taken from over 140 wild birds, and conclude that it is rare in free-living Jackass Penguins in their natural habitat Problems of prophylaxis in captive populations are discussed
TL;DR: Kelp Gull chicks are fed predominantly “natural” prey which indicates that the population increase may not be due to enhanced reproductive success, but to improved post-fledging ...
Abstract: Summary Steele, W.K. 1992. Diet of Hartlaub's Gull Larus hartlaubii and the Kelp Gull L. dominicanus in the southwestern Cape Province, South Africa. Ostrich 63:68-82. Hartlaub's Larus hartlaubii and Kelp Gulls L. dominicanus in the southwestern Cape feed on a wide range of prey species. On average, Kelp Gulls feed on larger-sized prey than do the smaller Hartlaub's Gulls. In an undisturbed environment the preferred foraging habitats of Hartlaub's and Kelp Gulls are rocky shores and open, sandy beaches (where sand mussels Donax serra are common) respectively. However, as a result of man's activities, several new foraging habitats have become available including croplands, fishing harbours and refuse dumps. The provision of supplementary food at these new foraging habitats is likely to be the cause of a recent population increase. Kelp Gull chicks are fed predominantly “natural” prey which indicates that the population increase may not be due to enhanced reproductive success, but to improved post-fledging ...
TL;DR: It is concluded that irregular, and periodic low periods of food production, are the primary reasons for sustaining low species richness and density of Forest birds.
Abstract: Summary Koen, J. H. 1992. Medium-term fluctuations of birds and their potential food resources in the Knysna Forest. Ostrich 63:21-30. The response by birds to fluctuating food sources in the Knysna Forest was investigated during a five year period. Fruits were irregularly produced by individual tree species but total production peaked during winter (June) of each year. The density and biomass of litter and soil surface invertebrates fluctuated both within and between years, with no regular seasonal peaks. Aerial invertebrates reached peak annual densities during summer. The total bird density within the study area was only correlated with fruit availability. Only a few of the individual bird species were correlated with the food categories but these correlations were not always easy to explain ecologically. It is concluded that irregular, and periodic low periods of food production, are the primary reasons for sustaining low species richness and density of Forest birds.
TL;DR: The Green Widowfinch Vidua codringtoni mimics the songs of the Redthroated Twinspot Hypargos niveoguttatus, its apparent foster species in Zimbabwe, Zambia and Malaŵi.
Abstract: Summary Payne, R. B., Payne, L. L. & Nhlane, M. E. D. 1992. Song mimicry and species status of the Green Widowfinch Vidua codringtoni. Ostrich 63:86-97. The Green Widowfinch Vidua codringtoni mimics the songs of the Redthroated Twinspot Hypargos niveoguttatus, its apparent foster species, in Zimbabwe, Zambia and Malaŵi. Of 38 male Green Widowfinches, 37 mimicked the twinspot; one mimicked a firefinch and not the twinspot. A wild-captured juvenile developed mimicry of twinspot song after six months and retained its mimicry through the next year. Male Green Widowfinches have glossy breeding plumage (green to blue), black wings, white bill and bright orange feet, a colour combination unlike other widowfinches in their range in southern Africa. Females are marginally distinguishable from other widowfinch species. Green Widowfinches occur together locally with Black V. funerea nigerrima, Purple V. purpurascens and Steelblue V. chalybeata Widowfinches and do not interbreed with them. The four species of widowfi...
TL;DR: Cooper et al. as discussed by the authors reported that the Caspian tern Sterna caspia occurs along the whole southern African coastline and on large river systems and water bodies away from the coast.
Abstract: Summary Cooper, J., Brooke, R.K., Cyrus, D.P., Martin, A.P., Taylor, R.H. & Williams, A.J. 1992. Distribution, population size and conservation of the Caspian Tern Sterna caspia in southern Africa. Ostrich 63: 58–67. The Caspian Tern Sterna caspia occurs along the whole southern African coastline and on large river systems and water bodies away from the coast. A total of 28 definite breeding localities has been recorded in southern Africa. Breeding has occurred recently at at least 14 coastal localities between Swakopmund, Namibia, and Lake St Lucia, Natal, South Africa. Inland breeding has been recorded in recent years at Sua Pan, Botswana and Kalkfonteindam, Orange Free State, South Africa. Based on censuses conducted between 1980 and 1991, the southern African breeding population is estimated to be of the order of 500 pairs, 91% of which breed coastally and 89% breed on islands. Up to 290 pairs (58%) bred at Lake St Lucia. Seventyone per cent of the 1980–1991 breeding population falls within eight natu...
TL;DR: In both sexes, a significant correlation was found between wing/tail and total head/culmen lengths and Bulging in P6 in males was significantly correlated with wing length.
Abstract: Summary De Swardt, D. H. 1992. Distribution, biometrics and moult of Gurney's Sugarbird Promerops gurneyi. Ostrich: 63:13-20. Gurney's Sugarbird Promerops gurneyi was studied at Lydenburg, from December 1986 until December 1990. Its distributional range coincides with the high mountainous veld types in association with Protea spp (mainly P. roupelliae). A total of 97 males (31,7%), 115 females (37,6%0) and 94 unsexed sugarbirds (30, 7%) were mistnetted and biometric and moult data recorded. The mean culmen, total head, tarsus, wing and tail lengths of males were significantly loner than those of females. No seasonal variation in the body mass of the sexes was recorded although males were heavier than females. In both sexes, a significant correlation was found between wing/tail and total head/culmen lengths. Bulging in P6 in males was significantly correlated with wing length. Primary moult occurred between September and March, coinciding with the breeding season. Primaries were moulted descendantly and se...
TL;DR: Brown et al. as discussed by the authors reported the distribution and status of the Bearded Vulture Gypaetus barbatus in southern Africa, which covers an area of about 35000 km2.
Abstract: Summary Brown, C. J. 1992. Distribution and status of the Bearded Vulture Gypaetus barbatus in southern Africa. Ostrich 62:1-9. The post-1980 breeding distribution of Bearded Vultures Gypaetus barbatus in southern Africa covers an area of about 35000 km2. Their foraging range is almost three times larger. The total southern African population consists of about 630 birds, comprising about 204 breeding pairs and 224 young birds. The breeding birds are distributed as follows: about 122 pairs in Lesotho, 42 in Natal (37 on the Drakensberg escarpment), 17 pairs in the Transkei, 16 in the northeastern Cape, four in QwaQwa and three in the Orange Free State.
TL;DR: Levels varied seasonally, with the highest found between May and September, and risk of increased mortality in full-grown birds was negligible but visceral fat of adult females contained DDE levels associated elsewhere with eggshell thinning and breeding failure in a related species.
Abstract: Summary Douthwaite, R.J., Hustler, C.W., Kruger, J. & Renzoni, A. 1992. DDT residues and mercury levels in Reed Cormorants on Lake Kariba: a hazard assessment. Ostrich 63: 123–127. Samples of liver and visceral fat from 86 cormorants Phalacrocorax africanus collected at the eastern end of Lake Kariba between January and October 1986 were analysed for 22 organochlorine compounds. Residues of four insecticides were detected but concentrations of hexachlorobenzene, Hch and lindane in liver did not exceed 0.3 mg kg−1 extractable lipid. Unaltered DDT, or its metabolites DDD and DDE, were found in every sample, almost all as DDE. Levels varied seasonally, with the highest found between May and September. Risk of increased mortality in full-grown birds was negligible but visceral fat of adult females contained DDE levels associated elsewhere with eggshell thinning and breeding failure in a related species. In a separate study, tissues from ten birds were analysed for mercury. Up to 13.6 mg mercury kg1 dry weight...
TL;DR: Little et al. as mentioned in this paper investigated the temporal and meteorological effects on calling activity of Greywing Francolin Francolinus africanus and assessed the use of call counts as an index of between year and between area variation in population density.
Abstract: Summary Little, R.M. & Crowe, T.M. 1992. Vocal behaviour of Greywing Francolin Francolinus africanus can be used to estimate population density. Ostrich 63:98-109. Four common calls of the Greywing Francolin Francolinus africanus are described acoustically, and their functions discussed. Data from 166 crepuscular call count surveys (2 472 counts) and 540 diurnal call counts were analysed to investigate the temporal and meteorological effects on calling activity, and to assess the use of call counts as an index of between year and between area variation in population density. Calling remained at high levels from August to April during the breeding season. Calling was most frequent at sunrise and sunset. Calling frequency and the number of calling coveys were significantly higher at sunrise than at sunset. Calling was concentrated in the 30 minute periods straddling sunrise and sunset, and peaked during the 15-minute periods before sunrise and before sunset. Calling activity was negatively correlated with w...
TL;DR: Van Der Merwe et al. as mentioned in this paper reported that the Whitefronted Plover Charadrius marginatus, a resident of the Alexandria dunefield, moves between the beach and dunes to feed.
Abstract: Summary Van Der Merwe, D., McLachlan A. & De Ruyck A. M. C. 1992. Partitioning of feeding habitats by Whitefronted Plovers Charadrius marginatus at a dune/beach interface. Ostrich 63:49-57. The Whitefronted Plover Charadrius marginatus, a resident of the Alexandria dunefield, moves between the beach and dunes to feed. It nests in slacks, one of the many habitats in the dunefield. The main prey items are insects in the dunes and bivalve siphons on the beach. Feeding activity on the beach is determined by the time of day, tide and wind. At wind speeds greater than 10,s-1 no feeding takes place in the intertidal zone. Below 10m.s−1 wind speed, feeding is influenced primarily by the time of day and secondarily by the state of the tide. Although feeding takes place at night, this occurs mainly during good light conditions. Feeding activity intensifies at dawn, irrespective of the state of the tide, 61% of total feeding effort occurring on the beach and 39% in the dunes.
TL;DR: Leucocytozoon struthionis Walker, 1912 is redescribed from blood smears prepared from ostriches in the Little Karoo area near Oudtshoorn, Republic of South Africa.
Abstract: Summary Bennett, GF, Huchzermeyer, FW, Burger, WP & Earle, RA, 1992 The Leucocytozoidae of South African Birds Redescription of Leucocytozoon struthionis Walker, 1912 Ostrich 63:83-85 Leucocytozoon struthionis Walker, 1912 is redescribed from blood smears prepared from ostriches in the Little Karoo area near Oudtshoorn, Republic of South Africa Neohapantotype and paraneohapantotype material is designated The redescription includes newly derived morphometric parameters not considered at the time of the original description It is suggested that the ostrich may be an abnormal host
TL;DR: The conservation status of the species is reviewed, the possible importance of temporary wetlands to the Slaty Egret is discussed, and the diet and feeding habits of immature birds are described.
Abstract: Summary Hines, C.J.H. 1992. Observations on the Slaty Egret Egretta vinaceigula in northern Namibia. Ostrich 63: 118–122. The Slaty Egret is an endemic African resident with a limited distribution in Botswana, Zambia and Namibia. Distribution records for Namibia are reviewed and information on movements and habitat preferences is given. Diet and feeding habits are described. Two colonies of Slaty Egrets containing eggs and chicks were found on temporary wetlands in eastern Bushmanland. Nests and eggs are described and egg measurements and weights given. The plumage of immature birds is described as well as the variation in adult plumages. The conservation status of the species is reviewed, and the possible importance of temporary wetlands to the Slaty Egret is discussed.
TL;DR: Observations of the breeding biology of the Quail Finch Ortygospiza atricollis supplemented with observations of breeding behaviour in captivity found breeding success was low, with most losses resulting from predation during either the egg-laying or incubation stages.
Abstract: Summary Nuttall, R.J. 1992. Breeding biology and behaviour of the Quail Finch Ortygospiza atricollis. Ostrich 63:110-117. During a study of the breeding biology of the Quail Finch Ortygospiza atricollis, observations of nest-building, egg-laying, incubation and nestling periods, and nestling development in a grassland near Pietermaritzburg, South Africa were supplemented with observations of breeding behaviour in captivity. Mean clutch size was 4,5 and eggs were laid at intervals of approximately one day. Incubation began after the third or fourth egg was laid. An incubation period of 15–16 days and an estimated nestling period of 18–19 days was recorded. Incubation and brooding are shared by both sexes. Breeding success was low (26,7% −28,6%), with most losses resulting from predation during either the egg-laying or incubation stages.
TL;DR: The distribution of the Wattled starling in South Africa has been investigated in this paper, where the authors described the species as nomadic and the pattern of occurrence does not suggest regular migration.
Abstract: Summary Craig, A. J. F. K. 1992. The distribution of the Wattled Starling in southern Africa. Ostrich 63:31-37. Dated distribution records of the Wattled Starling Creatophora cinerea have been assembled from the literature, museum specimens, atlas records, and other unpublished observations. The bulk of these records are from the period 1980–89. Breeding records are sparse, but breeding appears to be seasonal in the winter rainfall area. In summer rainfall areas nesting occurs from spring through to autumn, dependent on the presence of abundant insects. In most areas winter records (June to August) predominate, but in the eastern lowveld areas of South Africa Wattled Starlings are recorded most often in spring and summer. The species is correctly described as nomadic, and the pattern of occurrence does not suggest regular migration.