摘要:

SummaryAfter a comparison of the numbers of avian species counted by Kikkawa&Pearse (1969), Pianka&Schall (1981) and Blakerset al.(1984), statistical methods are used to evaluate the closeness of the relationship between these numbers and the main environmental parameters such as rainfall (used among other climatic parameters by Pianka&Schall) and the chief characteristics of vegetation and the land surface. While it is acknowledged that rainfall is of vital importance, it is shown here that its relevance acts indirectly through its influence on the vegetation, and particularly the height of the vegetation, which offers the greatest variety and number of avian niches. The closest statistical correlation is obtained from a combination of relative relief of the land surface, variety of vegetation types, height of the vegetation and closeness of the plant cover. Gradual spatial variations (clines) in the density of avian species are examined and the concept of eco-biological escarpment (steep spatial change in numbers) is introduced. Maps are presented to show the geographical patterns of clines and escarpments (latitudinal, longitudinal and oblique) in the numbers of avian species in Australia. Map 8 shows a synthesis of avian species clines, revealing the dominance of NE-SW and NW-SE discontinuities along the western and north-eastern Torresian boundaries.

ISSN:0158-4197    

DOI:10.1071/MU9920129

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

SummaryObservations are presented of the breeding biology of the Pheasant CoucalCentropus phasianinusat Townsville, north Queensland. Nests were dome-shaped structures, lined with eucalypt leaves and twigs, built close to the ground in grass clumps. Twelve of the 13 nests were associated with the introduced Chinee AppleZizyphus mauritiana.Nesting occurred early in the wet season and four broods were followed during development. Hatching was asynchronous, spread over up to six days. Nestlings fledged asynchronously and the mean nestling period of 12.6 days (range 10–15 days) was appropriate to a much smaller species. At fledging, young had attained only 40% of adult male weight, with wing 32% and tarsus 90% of adult measurement; they thus fledged well before they were fully grown, after a short nestling period. All four nests succeeded in fledging at least one young and it is suggested that fledging early in development is an adaptation that reduces nest predation.

ISSN:0158-4197    

DOI:10.1071/MU9920141

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

SummaryEstimates of the breeding status of the Wedge-tailed ShearwaterPuffinus pacificuson the Capricorn Group of islands in the southern Great Barrier Reef indicate that the size of the breeding population is much lower than previously thought (500 000 pairs). For the 1989–90 season 43% and 56% of burrows, on Heron and Erskine Islands respectively, supported breeding birds. Most occupied burrows featured lined nesting chambers. Burrow lengths ranged from 0.1 m to 2.35 m with a mean of 0.91 m. There was no relationship between burrow length and breeding activity.

ISSN:0158-4197    

DOI:10.1071/MU9920147

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

SummaryA Crested TemSterna bergiicolony containing 13 000–15 000 nesting pairs was located on North Bountiful Island in the Wellesley Group, Gulf of Carpentaria. This is Australia's largest known colony and may be the largest documented colony in the world. Breeding birds are thought to aggregate in autumn from foraging areas throughout the vast eastern Gulf of Carpentaria. The outer Wellesley Islands also support major colonies of Brown BoobiesSula leucogaster, Least FrigatebirdsFregata arieland a newly discovered colony of approximately 1000 pairs of nesting Roseate TemsSterna dougallii.Seabird nesting follows the summer monsoonal flooding and is presumably a response to nutrient enrichment of the Gulf by river runoff.

ISSN:0158-4197    

DOI:10.1071/MU9920152

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

SummaryForty-two nests of Yellow-eyed PenguinsMegadyptes antipodeswere dispersed in an 11 ha area of Middle Bay, Campbell Island, during the 1987–88 breeding season. Eighty-three per cent of eggs hatched. The mean hatch date was 26 November, 9 days later than that recorded on the South Island of New Zealand. Eighty-five per cent of chicks fledged at a rate of 1.4 chicks per nest. This level of success was comparable to that found during good seasons on South Island or in areas where predation levels on chicks is low. Chicks fledged at a mean weight of 5.1 kg, 108 days after hatching.

ISSN:0158-4197    

DOI:10.1071/MU9920157

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

SummaryManed DucksChenonetta jubatawere first seen in the study area, near Taralga, in the 1930s, when the first farm dams were built. This study tested the importance of farm dams by comparing numbers of Maned Ducks and their broods, in the periods September-December of 1981–83, on three pastoral properties with differing numbers of dams (40, 10, 14). There were significant differences among properties in numbers of Maned Ducks and their broods but, when compared on a per dam basis, there were relatively few differences in these two measures. Where differences occurred these were attributable to dams being close to where wheat was being fed to livestock, a strong predictor of relative abundance. The species used farm dams almost exclusively and not the creeks within the study area (1981–83), Most dams were used by Maned Ducks at least once; only small dams covered by emergent surface vegetation were not used. During breeding, Maned Ducks were usually found on dams within 400 m of tree hollows. Broods tended to stay on those dams close to where they were hatched although the size of the dam was also important through the fledging period. After breeding, the area of the dam was an important predictor of relative abundance of Maned Ducks. Most dams satisfied the ecological requirements of this species and this study provided evidence that the number of dams is the main determinant for the number of Maned Ducks and the number of broods hatched.

ISSN:0158-4197    

DOI:10.1071/MU9920163

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

SummaryI report observations of honeyeaters at sugar-water feeders conducted over two years in heathland near Sydney. Eight to 14 sugar-water feeders were distributed over a 4 ha patch of heath, and placed away from existing territories to minimise the chance of feeders being monopolised by a few birds. All common species of honeyeaters used feeders, and feeders were used extensively during all months except May-July (when nectar fromBanksia ericifoliawas abundant) and November-January (when there were few honeyeaters on the heath). Incidence of aggression at feeders was low, and most birds that were excluded could feed as soon as the aggressor finished using the feeder. Feeders were occasionally defended by large honeyeaters (Little Wattlebirds, Noisy Friarbirds and Red Wattlebirds) but these species were relatively uncommon. Feeders were never defended by New Holland or White-cheeked Honeyeaters, which were the most common species and defended breeding territories on the heath. Consequently, the majority of feeders were always freely accessible, so that they provided easy access to energy similar to that provided by rich and abundant nectar sources such asBanksia ericifolia.I conclude that feeders can be used to test whether correlations between nectar abundance and honeyeater abundance, behaviour and breeding are caused by responses to changes in energy availability.

ISSN:0158-4197    

DOI:10.1071/MU9920170

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9920181

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9920184

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9920187

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor