摘要:

SummaryAumann, T. (1990). Use of stones by the Black-breasted BuzzardHamirostra melanosternonto gain access to egg contents for food.Emu90, 141–144.A captive Black-breasted BuzzardHamirostra melanosternoncracked Domestic ChickenGallus galluseggs by using its bill to throw 15–65 g rounded stones at them in order to feed on the contents. The throwing method, feeding and post-feeding behaviour are described. Throwing accuracy improved during a series of trials conducted over 26 days. The egg-breaking activity is discussed in terms of tool usage and in terms of learned versus non-learned behaviour.

ISSN:0158-4197    

DOI:10.1071/MU9900141

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryLenz, M. (1990). The breeding bird communities of three Canberra suburbs.Emu90, 145–153.The composition and size of the breeding bird populations of three plots with garden city character in Canberra, Australian Capital Territory, were each estimated for one breeding season between 1978 and 1981 using the modified territory mapping method. The number of territories per 10 ha (abundance) were 58.4 (Ainslie). 56.1 (Hackett) and 91.2 (Aranda). Species numbers in the sample areas were 26 (Ainslie, Hackett) and 20 (Aranda). Territories of introduced species, mainly House SparrowPasser domesticus(44.8–63.5%), Common StarlingSturnus vulgaris(6.8–23.0%) and BlackbirdTurdus merula(1.27.6%), comprised between 71–79% of the total number of territories. The only dominant native bird species was the SilvereyeZosterops lateralis(5.9–10.3%). 40–69% of all bird species ranked as rare (each<1 % of the total population). The abundances of native bird species, excluding the Silvereye, were 5.9 T/10 ha in Ainslie, 8.5 T/10 ha in Hackett and 18.9 T/10 ha in Aranda, probably reflecting the extent of native trees and shrubs in streets and gardens. In Ainslie, the vegetation was composed largely of exotic species. In Hackett, native trees (eucalypts) were more common but distributed unevenly. In Aranda, native vegetation dominated, many trees had been retained from the original woodland. Aranda supported a significantly higher population of exotic birds (65 T/10 ha) than Ainslie (46.5 T/10 ha) and Hackett (44.2 T/10 ha); many cavities in the original eucalypts provided House Sparrows and Common Starlings with more nest sites than were available in the other plots.

ISSN:0158-4197    

DOI:10.1071/MU9900145

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryWhitehead, P.J.&Tschirner, K. (1990). Eggs and hatchlings of the Magpie GooseAnseranas semipalmata Emu90, 154–160.The Magpie Goose produces unusually large clutches of eggs (mean = 9.8) slightly smaller in size (mean = 104.2 g) than predicted from allometric equations relating egg size to female body weight in waterfowl. Incubation temperature (37.1°C) is similar to that achieving optimum hatching rates in the Anatidae. The incubation period of 28 days is within the range reported for other waterfowl, including anserine geese. Rate of evaporative water loss from eggs under natural conditions may be low compared with many birds, including other waterfowl. Hatchlings from artificially incubated eggs weighed 74.6 g, 68.6% of estimated fresh weight of eggs from which they hatched: weight of enclosed yolk averaged 11.3% of hatchling weight. Hatchling weight, head, wing and leg measurements were significantly positively correlated with egg size. Within clutches, the last eggs to hatch were lighter and produced smaller hatchlings. Hatchling dimensions did not differ significantly between sexes.

ISSN:0158-4197    

DOI:10.1071/MU9900154

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryBaker-Gabb, D.J., Benshemesh, J.S.&Maher, P.N. (1990). A revision of the distribution, status and management of the Plains-wandererPedionomus torquatus Emu90, 161 -168.On 310 nights during mid–1982–86, 420 Plains-wanderers were banded, mainly on two Riverina grazing properties. Approximately 3% of 750 km2ground-searched was sparse grassland suitable for Plains-wanderers, as was 1% of an aerially-searched area ten times larger. Home range size was 12 ha. It was calculated that 830 Plains-wanderers occur in 7500 km2of the Riverina and estimated that fewer than 5500 birds occur in the whole of the region. Thirty-eight breeding events were recorded in spring or in summer if rains fell. Regular production of broods of 2–4 chicks and the Plains-wanderer's ability to breed in its first year indicate a capacity to recover quickly from low population numbers. In the Riverina and southwest Queensland overgrazing is now the main factor limiting the distribution and abundance of Plains-wanderers. Elsewhere, cultivation replaces overgrazing as the main limiting factor. Two options for management to improve the conservation status of the species are suggested: the acquisition of reserves ideally containing at least 450 ha of suitable native grassland, or the negotiation of covenants with landowners that prevent burning, cultivation or overgrazing of areas suitable for Plains- wanderers.

ISSN:0158-4197    

DOI:10.1071/MU9900161

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryThompson, J. (1990). The sex and age-related distribution of Bar-tailed Godwits in Moreton Bay, Queensland, during the northward migration.Emu90, 169–174.Evidence is presented for the age-related distribution of Bar-tailed Godwits in Moreton Bay, Queensland, during the northward migration in 1989. The age-related distribution was deduced from plumage characteristics, sex ratio patterns and the general distribution of Bar-tailed Godwits in the Bay. A‘natural experiment’at a sewage outfall is described to help explain the age-related distribution. Despite the high densities of birds on the intertidal area adjacent to the outfall, the area appeared to be used by a relatively small proportion of adults. It is suggested that the nature of the intertidal habitat near the sewage outfall is less suited to godwits than island locations in the Bay. Qualitative differences in habitat are suggested to play an important role in determining the overall distribution of Bar-tailed Godwits in Moreton Bay.

ISSN:0158-4197    

DOI:10.1071/MU9900169

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryTarburton, M.K. (1990). Breeding biology of the Atiu Swiftlet.Emu90, 175–179.The Atiu SwiftletAerodramus leucophaeus sawtellibuilds most of its nests from lichen, fibre from the crown of the coconut tree and saliva. Nests were smaller and less often placed in total darkness than those of other species that also have two chicks. Most nests were built in September and the last chicks probably fledged in April. Both parents share the incubation of their two white eggs and both begin moulting their flight feathers while incubating. As well as replacing lost eggs and young broods some parents relaid after successfully fledging their first brood. The average weight of newly hatched chicks was 1.1 g and at the time of fledging (53 days later) was 9.5 g. Each brood was fed six times a day. Chicks do not have any of the parasitic louse flies that are common on other swiftlets in the south-west Pacific but they are killed by crabs. Atiu sustained 380 breeding Atiu Swiftlets during the season, which means the density was 7.1 ha per breeding bird.

ISSN:0158-4197    

DOI:10.1071/MU9900175

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryZotier, R. (1990). Breeding ecology of a subantarctic winter breeder: the Grey PetrelProcellaria cinereaon Kerguelen Islands.Emu90, 180–184.The breeding ecology of the little known, winter breeding, Grey PetrelProcellaria cinereawas studied on the Kerguelen Archipelago. Adults returned to breed in February. The period of egg laying was less extended than has been previously suggested. Laying took place in early April, and hatching in late May to early June. The fledging period, 120 to 160 days, is the longest known among the petrels. The frequency at which chicks were fed affected the length of the fledging period. A particularly long fledging period is common to the southern winter breeders.

ISSN:0158-4197    

DOI:10.1071/MU9900180

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryFrench, K. 1990. Evidence for frugivory by birds in montane and lowland forests in south-east Australia.Emu90, 185–189. Fruit consumption by birds in forests near Healesville, Victoria was determined in 1987 and 1988 by analysing faecal samples of trapped birds. Evidence of frugivory was found in the faeces of 18 species of birds and a further three species were observed eating fruit. Five species of birds consumed large quantities of fruit during autumn while most birds appeared to supplement their basically insectivorous diet with small quantities of fruit. Of the nine common species of plants that produced fleshy fruits during the study, only six were evident in faeces. Some non-fleshy fruits were also eaten. Most species defaecated seeds intact; however, Crimson Rosellas were identified as the only seed predators.

ISSN:0158-4197    

DOI:10.1071/MU9900185

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

SummaryBriggs, S.V. (1990). Sexual and annual differences in activity budgets of Maned DucksChenonetta jubata. Emu90, 190–194.Maned Ducks fed for between 28% (males) and 32% (females) of the day in summer, and 56% (males) and 64% (females) in autumn. Females always fed more than males but males were more alert. Flock size and vigilance, as well as feeding and resting times, were inversely related in both sexes. I suggest that females fed more than males and males were more alert than females, to allow females to maintain body condition during the year. Females in better condition prior to breeding would build up fat reserves for laying and incubation more quickly, providing reproductive advantages to both pair members.

ISSN:0158-4197    

DOI:10.1071/MU9900190

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9900195

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor