Showing papers in "Ostrich in 1986"
TL;DR: A new census method for penguins tested on Jackass Penguins Spheniscus demersus in 1986 and its implications for future census methods are described.
Abstract: Randall, R. M., Randall, B. M., Cooper, J. & Frost, P. G. H. 1986: A new census method for penguins tested on Jackass Penguins Spheniscus demersus. Ostrich 57: 211–215 A census method for Jackass P...
27 citations
TL;DR: Macdonald et al. as mentioned in this paper investigated the range expansion of the Pied Barbet leucomelas into fynbos, karoo, grassland and mesic savanna areas.
Abstract: Summary Macdonald, I A W 1986 Range expansion in the Pied Barbet and the spread of alien tree species in southern Africa Ostrich 57: 75–94 Apparent range expansions of the Pied Barbet Lybius leucomelas into fynbos, karoo, grassland and mesic savanna areas have occurred this century The number of loci from which the barbet was recorded in each biome prior to 1903, from 1904 to 1963 and from 1964 to 1984 was analysed Initially recorded from 1 to 2% of each biome's loci, the percentage increased most rapidly in the fynbos to reach 53% in the latest period Savanna (31%), grassland (26%), karoo (16%) and forest (3%) had significantly lower reporting frequencies in this latest period The expansion into the fynbos of the southwestern Cape is analysed in detail Analyses of field-card records showed that the reporting frequency of L leucomelas in the southwestern Cape increased from 9,7% to 27,5% between the period 1950–1979 and 1982–1984 The reporting frequency tended to be higher in those areas mappe
24 citations
TL;DR: Rainfall in the latter part of the rainy season appeared to influence early and late laying pairs of Tawny Eagles in the Hwange National Park, Zimbabwe.
Abstract: Summary Hustler, K. & Howells, W. W. 1986. A population study of Tawny Eagles in the Hwange National Park, Zimbabwe. Ostrich 57: 101–106. Tawny Eagle Aquila rapax breeding success has been monitored in the Hwange National Park, Zimbabwe from 1973–1984. There were 1044 breeding pair years with 640 chicks reared; an average of 0,61 chicks/breeding paid year. The average number of pairs breeding each year was 72,4%. Thirty-one percent of all breeding attempts failed; most during nest-building (59%). Rainfall in the latter part of the rainy season appeared to influence early and late laying pairs. Two-egg clutches were most common (76%) and 65% of all one-egg clutches laid failed to produce chicks. Several factors which may influence breeding success are discussed.
21 citations
TL;DR: Investigation of Macaroni Penguins Eudyptes chrysolophus and Rockhopper Penguins at Marion Island found new feathers began developing under the skin before the birds returned ashore to moult, and only began protruding through the skin about five days later when they were already over half their final length.
Abstract: Summary Brown, C. R. 1986. Feather growth, mass loss and duration of moult in Macaroni and Rockhopper Penguins. Ostrich 57:180-184. The development of new feathers, loss of body mass and the duration of moult were investigated in Macaroni Penguins Eudyptes chrysolophus and Rockhopper Penguins E. chrysocome at Marion Island, southern Indian Ocean. New feathers began developing under the skin before the birds returned ashore to moult, and only began protruding through the skin about five days later when they were already over half their final length. Feather synthesis was complete by 21 days after the birds returned ashore. Loss of body mass was similar to previous observations for the species, but previous reports on the duration of moult do not take into account that moult begins while the birds are still at sea.
18 citations
TL;DR: The range of the Ground Hornbill has declined and the birds have withdrawn from the peripheral grassland areas and is assumed to be a consequence of the increase in human population.
Abstract: Summary Vernon, C. J. 1986. The Ground Hornbill at the southern extremity of its range. Ostrich 57:16–24. All records of the Ground Hornbill Bocorvus leadbeateri south of 31°s are reviewed. The distribution of the species coincides with the grassland and forest veld types. The range has declined and the birds have withdrawn from the peripheral grassland areas. This decline is assumed to be a consequence of the increase in human population. The mean size of the Ground Hornbill groups is 3,5 birds.
17 citations
TL;DR: Brooke et al. as mentioned in this paper found that Greyheaded and yellownosed albatross species regurgitated similar squid (by species and size), and these squid were similar to those found in previous studies of the diet of Wandering, Sooty and Lightmantled sooty Albatrosses at the Prince Edward Islands.
Abstract: Summary Brooke, M. De L. & Klages, N. 1986. Squid beaks regurgitated by Greyheaded and Yellownosed Albatrosses, Diomedea chrysostoma and D. chlororhynchos, at the Prince Edward Islands. Ostrich 57: 203–206. Squid regurgitated by Greyheaded and Yellownosed Albatrosses at the Prince Edward Islands were predominantly two onychoteuthid species, Kondakovia longimana and Moroteuthis knipovitchi. Both squid are characteristic of cold, Antarctic waters and may have been caught south of the Antarctic Convergence, some 350 km to the south of the breeding station. Both albatross species regurgitated similar squid (by species and size), and these squid were similar to those found in previous studies of the diet of Wandering, Sooty and Lightmantled Sooty Albatrosses at the Prince Edward Islands.
17 citations
TL;DR: The prey species taken are broadly similar but potential interspecific competition for food is presumably reduced, since the petrels have different breeding seasons with non-overlapping chick-rearing periods.
Abstract: Summary Schramm, M. 1986. The diet of chicks of Greatwinged, Kerguelen and Softplumaged Petrels at the Prince Edward Islands. Ostrich 57: 9–15. Stomach contents of chicks of Greatwinged Petrels Pterodroma macroptera, Kerguelen Petrels P. brevirostris and Softplumaged Petrels P. mollis collected at the Prince Edward Islands were analysed. Chicks of all three species were fed primarily on cephalopods (90%, 70% and 89% by mass of solids in the stomach contents, respectively) supplemented by crustaceans (6% in P. macroptera, 24% in P. brevirostris and 10% in P. mollis) and fishes. The prey species taken are broadly similar but potential interspecific competition for food is presumably reduced, since the petrels have different breeding seasons with non-overlapping chick-rearing periods.
17 citations
TL;DR: It is suggested that the Lesser Jacana's small egg necessitates a high rate of nest attendance which could account for the sociosexual differences between this species and other jacanas.
Abstract: Summary Tarboton, W. R. & Fry, C. H. 1986. Breeding and other behaviour of the Lesser Jacana. Ostrich 57: 233–243. Breeding Lesser Jacanas were studied briefly at Lake St Lucia (Zululand), Hwange (Zimbabwe) and the Okavango Delta (Botswana). The species is monogamous and breeding birds are dispersed as territorial pairs. Male and female share incubation nearly equally, alternating at the nest in shifts averaging 39min; the eggs are attended (incubated or shaded), on average, for 82% of the daylight hours. Eggs are incubated by holding them against the breast with the underside of the wings; at least one chick was seen carried under a parent's wing. The pullus, foraging behaviour, courtship and vocalisations are described. It is suggested that the Lesser Jacana's small egg necessitates a high rate of nest attendance which could account for the sociosexual differences between this species and other jacanas.
16 citations
TL;DR: The South African Cliff Swallow Hirundo spilodera breeds in dense colonies usually under man-made concrete bridges, with a recruitment rate of 0,9 young: 1 adult per season.
Abstract: Summary Earle R. A. 1986. The breeding biology of the South African Cliff Swallow. Ostrich 57: 138–156. The South African Cliff Swallow Hirundo spilodera breeds in dense colonies usually under man-made concrete bridges. The clutch size is 1–4 eggs but most 4-egg clutches are probably the result of conspecific brood parasitism. The incubation period averages 14,6 days and the fledling period 24,1 days. Although only the female Cliff Swallow has a featherless brood-patch, both males and females incubate effectively. Nestlings reach a maximum weight of up to 31 g between 19 and 22 days, about 10 g more than average adult weights. This weight increase of nestlings is mostly the result of an increase in water content of the body. Both parents feed the chicks, with the highest rate of feeding during the midday hours. In all, 56% of all eggs laid produced flying young, with a recruitment rate of 0,9 young: 1 adult per season.
15 citations
TL;DR: Nest, egg and adult biometrics are given together with observations of incubation behaviour, and potential threats to this flightless endemic species are discussed.
Abstract: Summary Watkins, B. P. & Furness, R. W. 1986. Population status, breeding and conservation of the Gough Moorhen. Ostrich 57: 32–36. The Gough Moorhen Gallinula comeri holds territories of about 5000m2 on Gough Island, where there may be 2 000–3 000 pairs. Scavenging from petrel carcasses partly eaten by Subantarctic Skuas Catharacta antarctica seems to be an important feeding method. Nests are constructed in tussocks with a tunnel entrance. Nest, egg and adult biometrics are given together with observations of incubation behaviour, and we discuss potential threats to this flightless endemic species.
15 citations
TL;DR: Analysis of nest-entrance orientation indicated that penguins preferred nest sites with east-facing entrances, and an increase in moisture of nest material had a significant adverse effect on tick numbers, while the other variables had little influence.
Abstract: Summary Daturi, A. 1986. A preliminary study of tick populations in Jackass Penguin nests on Marcus Island, South Africa. Ostrich 57:95-100. During April to August 1984, 136 Jackass Penguin nests were sampled to determine the population levels of the argasid tick Ornithodoros capensis. Nests were classified according to seven variables: moisture of substratum and of nest material, volume of nest material, nest site, nest-entrance orientation, occupant status and coloniality. The classes within each variable were tested statistically to determine their influence on adult/nymphal and larval tick distributions. An increase in moisture of nest material had a significant adverse effect on tick numbers, while the other variables had little influence. Analysis of nest-entrance orientation indicated that penguins preferred nest sites with east-facing entrances. The results were compared with those from Peruvian islands.
TL;DR: Bank Cormorants sometimes defecate onto their nests to make the nests better able to withstand rough seas, and both sexes occasionally steal nest material from the nests of neighbours.
Abstract: Summary Cooper, J. 1986. Biology of the Bank Cormorant, Part 4: Nest construction and characteristics. Ostrich 57: 170–179. Bank Cormorants Phalacrocorax neglectus construct their nests of material gathered by diving. Males undertake diving bouts of approximately 3–5 min, made up of several dives lasting on average 28 s. Nest material is gathered throughout the breeding cycle: number of diving bouts per day varies from a mean of 7,6 during pre-egg laying to 1,5 bouts per day when rearing young in the nest. Nest building recommences within 24 h of loss of nest due to storms. Both sexes occasionally steal nest material from the nests of neighbours. Bank Cormorants sometimes defecate onto their nests. This is assumed to make the nests better able to withstand rough seas. Nest construction takes approximately 34 d, a period similar to that of other ground-nesting species of cormorants. Construction of a nest in 34 d represents 238 diving bouts of a total duration of 18 h. Nests are heavy (up to 6 kg) and are ...
TL;DR: Dowsett, R. J. & Dowsett-Lemaire, F. 1986.
Abstract: Summary Dowsett, R. J. & Dowsett-Lemaire, F. 1986. Homing ability and territorial replacement in some forest birds in south-central Africa. Ostrich 57: 25–31. Forty-three colour-ringed birds of 11 species were translocated from one area of forest patches to another, six km distant, on the Nyika Plateau, Malawi. Only the Starred Robin Pogonocichla stellata and some Cape Batis Batis capensis showed homing ability and returned. Six birds were relocated in the release area, two establishing new territories there (Mountain Yellow Warbler Chloropeta similis, Whitetailed Crested Flycatcher Elminia albonotata). In the vacated area, empty territories of the Barthroated Apalis Apalis thoracica were filled and missing mates replaced within a day, presumably by birds from a local non-breeding surplus. Otherwise territorial replacements in the vacated area took several weeks (Fulleborn's Black Boubou Laniarius fuelleborni) to several months (Oliveflanked Robin Cossypha anomala), and were not completed almost three yea...
TL;DR: Estimates of initial mortality are negatively correlated with total rainfall during the breeding season, indicating that stormy weather contributes to breeding success, presumably through increasing food availability.
Abstract: Summary Underhill, L. G. & Underhill, G. D. 1986. An analysis of the mortality and survival of Hartlaub's Gull. Ostrich 57: 216–223. Ringing recoveries of Hartlaub's Gulls Larus hartlaubii ringed at Robben Island and Rondevlei are analysed. The variation in the recovery rate between cohorts of chicks ringed on Robben Island on the same day and between years is attributed to initial mortality (mortality after ringing but before reaching the mainland). Estimates of initial mortality are negatively correlated with total rainfall (a measure of storminess) during the breeding season, indicating that stormy weather contributes to breeding success, presumably through increasing food availability. The survival probabilities of first-year, second-year and adult Hartlaub's Gulls are estimated, and found to be independent of year.
TL;DR: A colour-banded population of Fiscal Shrikes Lanius collaris was studied for two-and-a-half years near Lake Naivasha, Kenya, and found that the amount of time the breeding female incubated or brooded young was related to the number of prey items brought to the nest by the breeding male.
Abstract: Summary Zack, S. 1986. Breeding biology and inter-territory movements in a Fiscal Shrike population in Kenya. Ostrich 57: 65–74. A colour-banded population of Fiscal Shrikes Lanius collaris was studied for two-and-a-half years near Lake Naivasha, Kenya. Annual survival was 39%, but since 25% of the colour-banded adults were known to have resided in two or more territories, this probably is an overestimate of mortality, because of dispersal outside the study site. I detected no sexual differences in survival. The study site contained from five to 1 pairs. Young birds fledged from only 15% of the nests I found. Only eight of the 17 pairs studied produced any young; these eight pairs averaged 1,89 young per nest. The amount of time the breeding female incubated or brooded young was related to the number of prey items brought to the nest by the breeding male. Males brought 26% of their captured prey to the nest, and the items brought were biased toward the longer prey items. Small prey items were rarely broug...
TL;DR: Wilson et al. as mentioned in this paper studied the nest building activities of Hamerkops in central Mali for more than four years and found that the nest is a huge enclosed structure, of a type unusual in non-passerine birds.
Abstract: Summary Wilson, R. T. & Wilson, M. P. 1986. Nest building by the Hamerkop Scopus umbretta. Ostrich 57: 224–232. Nest building activities of Hamerkops in central Mali were studied for more than four years. The nest is a huge enclosed structure, of a type unusual in non-passerine birds. Nest height above ground varies with the availability of suitable sites, and the entrance hole direction is related to the inclination of the tree. Construction is a joint undertaking by both members of a pair, round trip times in transporting material averaging 3 min 20 s. Females spend significantly more time on the nest than males during building. Most activity occurs during the early morning with two lesser peaks in the late morning and towards sunset. Nests are built all the year round, but there is a significant difference in numbers built in different months. Each pair of birds builds between 2,9 and 4,5 nests per year. No strong territoriality is evident, birds building in a home range area, occupying nests for relat...
TL;DR: The response of both species to playback of their calls is described and playback of Crested and Blackcollared Barbet calls attracted all “hole roosters” in the vicinity, regardless of phylogenetic relationship or song-type, indicating competition for roosting cavities.
Abstract: Summary Ward, D. 1986. Vocalizations and associated behaviour of Crested and Blackcollared Barbets. Ostrich 57: 129–137. The Blackcollared Barbet has a complex antiphonal duet which is initiated by vocal and visual signalling between members of a pair. The Crested Barbet's duet is not synchronized and may consist of a variety of combinations of trilling and grating calls depending on a pair's repertoire. The response of both species to playback of their calls is described. Playback of Crested and Blackcollared Barbet calls attracted all “hole roosters” in the vicinity, regardless of phylogenetic relationship or song-type, indicating competition for roosting cavities.
TL;DR: Leach's Storm Petrel Oceanodroma leucorhoa vocalizations were heard regularly from late October to late January at night at St Croix Island, South Africa as discussed by the authors.
Abstract: Summary Randall, R. M. & Randall, B. M. 1986. The seasonal occurrence of Leach's Storm Petrel Oceanodroma leucorhoa at St Croix Island, South Africa. Ostrich 57: 157–161. Leach's Storm Petrel Oceanodroma leucorhoa vocalizations were heard regularly from late October to late January at night at St Croix Island. Initial identification based on vocalizations was confirmed following live trapping at a burrow. Behaviour was similar to that on northern hemisphere breeding grounds, but only one individual appeared to visit the island. Some individuals of the species probably migrate regularly to southern Africa, but the scarcity of such records may be due to their oceanic distribution and nocturnal island visits.
TL;DR: Cyrus et al. as mentioned in this paper studied the seasonal and spatial distribution of Redheaded Quelea (Quelea erythrops) in South Africa and found that the species does not occur as regularly in the south as in the north.
Abstract: Summary Cyrus, Digby P. 1986. Seasonal and spatial distribution of Redheaded Quelea (Quelea erythrops) in South Africa. Ostrich. 57: 162–169. There are 48 records of Redheaded Quelea Quelea erythrops occurring in South Africa. Most are for the summer and early autumn months from October to April and all are restricted to the low lying eastern coastal areas. The pattern of occurrence in South Africa is similar to that in adjoining countries to the north; the species does not however occur as regularly in the south. Breeding or attempted breeding has been recorded on six occasions. This shows the typical pattern of occurrence of a species at the southern limit of its distribution. There is some evidence to suggest that its occurrence may be associated with “wet” years when rainfall is above average. The Redheaded Quelea may be considered as a rare and irruptive summer vagrant to South Africa, which only breeds when conditions are suitable.
TL;DR: Comparisons are made between the Red-billed Quailfinch and the other two Ortygospiza species which occur in Zambia in respect of distribution, habitat, seasonality, vocalizations and breeding data.
Abstract: Summary Penry, E. H. 1986. Notes on the biology of the Red-billed Quailfinch Ortygospiza gabonensis in Zambia. Ostrich 57: 193–202. In April 1977 a nest of the Red-billed Quailfinch was discovered in Chingola, Zambia. The nest and eggs of this species were previously undescribed and subsequently further nests were found. Notes were kept on this poorly documented species between 1976 and 1979. Comparisons are made between the Red-billed Quailfinch and the other two Ortygospiza species which occur in Zambia in respect of distribution, habitat, seasonality, vocalizations and breeding data. Following Traylor (1963) the Red-billed Quailfinch is treated as a distinct species.
TL;DR: Hockey et al. as mentioned in this paper reviewed the records of rare scolopacid waders in southern Africa and found that 374 records of 15 species are accepted: seven of four Nearctic species, 51 of four Holarctic species and 316 of seven Palaearctic species.
Abstract: Summary Hockey, P. A. R., Brooke, R. K., Cooper, J., Sinclair, J. C. & Tree, A. J. 1986. Rare and vagrant scolopacid waders in southern Africa. Ostrich 57: 37–55. Records of rare scolopacid waders in southern Africa are reviewed. 374 records of 15 species are accepted: seven of four Nearctic species. 51 of four Holarctic species and 316 of seven Palaearctic species. Their spatial and temporal (year and season) occurrence is analysed and their habitat requirements in southern Africa are described.
TL;DR: Clancey et al. as discussed by the authors found that good morphological differences exist, which, when correlated with the widely differing annual cycle, warrant the arrangement of the populations into northern and southern subspecies.
Abstract: Summary Clancey, P. A. 1986. Breeding season and subspecific variation in the Redheaded Quelea. Ostrich 57: 207–210. The Afrotropical Redheaded Quelea Quelea erythrops, originally described from Sao Tome, Sao Tome e Principe, in the Gulf of Guinea, has a wide if uneven range throughout the moister and more open savannas of Africa. Study of males in breeding dress in museum collections and of relevant data from the literature shows that the populations breeding to the north of the Equator nest at different times of the year to those in the south. No geographical races of the present species are currently recognised, but it is now found that good morphological differences exist, which, when correlated with the widely differing annual cycle, warrant the arrangement of the populations into northern and southern subspecies. A name is introduced for the southern assemblage of populations.
TL;DR: A pair of African Goshawks Accipiter tachiro began nest-building in November 1982 and one of the two young birds took its first flight on 11 February and both young fledged successfully.
Abstract: Summary Dewhurst, C. F. 1986. The breeding ecology of the African Goshawk at Karen, Nairobi, Kenya. Ostrich 57: 1–8. A pair of African Goshawks Accipiter tachiro began nest-building in November 1982. Eggs hatched on 7 January and one of the two young birds took its first flight on 11 February. Prey fed to the juveniles consisted of birds, chameleons, a toad and a Bush Squirrel, The nest was vacated in mid-February and the juveniles left the nest area during the latter part of March. Both young fledged successfully. The following year both young from the second nesting were killed before they left the nest.