摘要:

SUMMARYLoyn, R.H. 1985. Bird populations in successional forests of Mountain AshEucalyptus regnansin central Victoria. Emu 85: 213–230.Bird populations were estimated from 1977 to 1979 by mapping territories and by an“area search”method in stands of differing age (regenerating after wildfire or harvesting eucalypts) in the Victorian Central Highlands mainly near Toolangi. The aims were to assess effects of harvesting (followed by burning and artificial regeneration) and provide data on populations and ecology of birds inhabiting this distinctive forest type. Mountain Ash forests grow in high rainfall areas and the trees can reach heights of 100 m; they usually grow as even-aged stands and 79% of Mountain Ash forests in the Central Highlands has regenerated after severe fires in 1939.About 65 species of birds were found to be regular inhabitants of Mountain Ash forests and associated plant communities. All except the Pink Robin breed also in foothill gullies. Several species that are common in drier foothill forests, were absent from Mountain Ash forests. The commonest species were those that feed in the dense shrub layer or from damp ground below. Some insectivorous birds that were abundant in summer (e.g. Golden WhistlerPachycephala pectoralis, Grey FantailRhipidura fuliginosa)left Mountain Ash forests for the winter. Winter food sources were limited and the most important were blossoms of Mountain CorreaCorrea lawrenciana, invertebrates in damp leaf litter, and invertebrates or carbohydrate exudates from hanging bark of Mountain Ash or branches and trunks of Silver WattleAcacia dealbata.Habitats and interactions between various bird species are described.Bird population densities were low in the first three years after harvesting but some species were confined to open stands of this age. Other forest birds returned rapidly as eucalypts and understorey species regenerated. Populations were as high in 39-year-old regrowth as in older stands though some species (mainly those that need tree hollows for nesting) were more common in older forest. Implications for management are discussed.

ISSN:0158-4197    

DOI:10.1071/MU9850213

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

SUMMARYWingham, E.J. 1985. Food and feeding range of the Australasian GannetMorus senator(Gray). Emu 85: 231–239.Regurgitations analysed over three seasons (1978–80) indicated that PilchardsSardinops neopilchardus, both numerically and by weight, were the most common prey species of the Australasian Gannet at Motukaramarama. The next most common species were: numerically, AnchoviesEngraulis australisand by weight, Jack MackerelTrachurus novaeselandiae.It is thought that relative abundance of prey analysed reflects their abundance. Prey between 11–20 cm comprised 77% of the Gannet's diet.A further two prey species: SpratSprattus antipodumand KahawaiArripis truttawere recorded, bringing the known food of the Gannet to 15 species.The average adult Gannet regurgitated food equal to 11 % of its body weight (or 259 g and 2,000 Kj), whereas the average daily energy requirements were estimated at 2,844 Kj/day, or 353 g of food.An average feeding range of 268 km (range = 86–450 km) was estimated from the time adults spent away from the colony, resighting of marked birds and from recoveries of banded, breeding adults.

ISSN:0158-4197    

DOI:10.1071/MU9850231

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

SUMMARYHULSMAN, K. and LANGHAM, N.P.E. Breeding biology of the Bridled TernSterna anaethetus.Emu 85: 240–249.Features of breeding Bridled Terns can be considered as either anti-predator or other adaptations. Each anti-predator feature acting by itself or with others can decrease the likelihood of gulls preying on eggs and/or chicks. Anti-predator features include nesting under cover, dispersion of nests, cryptic colour of eggs and chicks, behaviour of chicks and adults, defeacating away from the nest and fast initial growth of chicks. However, other features can increase the likelihood of gulls preying on young. These include asynchronous laying and hatching and not removing egg shells from nests.Breeding success of Bridled Terns at One Tree Island, Great Barrier Reef was high because: (1) predation on their eggs and chicks was lower than on those of other terns, (2) their ability to fast for longer periods than, for example, Crested TernSterna bergiichicks buffered them from the effects of cyclonic weather.Growth rate of Bridled chicks may depend on the ability of, and the effort made by, their parents to transport food to them as well as the nutrient composition of their diet. We suggest that dietary differences are responsible for differences in the timing of adults' moulting in the Seychelles and Australia.

ISSN:0158-4197    

DOI:10.1071/MU9850240

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9850250

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9850257

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9850261

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9850264

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9850267

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9850269

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9850271

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor