摘要:

SummaryThe diets of three firetail finches were assessed by sampling seeds from the crops of wild—caught birds. Red—browedEmblema temporalisand Diamond FiretailsE. guttatafed predominantly on the seeds of introduced grasses, which also contributed significantly to the diet of Beautiful FiretailsE. bella.Firetails selected seeds that were 0.4–1.4 mm wide and 1–3 mm long because they were easiest to de-husk. Loss of native seed species was not responsible for the decline of Beautiful and Diamond Firetails.

ISSN:0158-4197    

DOI:10.1071/MU9940001

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

SummaryThis paper examines factors that influence the ability of area searches to census the complete bird population at a site. Such factors included duration and repetition of census periods, density of vegetation, density of individuals of species, weather and time of day. Total time spent on the site was found to be more important than the duration or the number of repetitions of the census period, especially in sites with a dense understorey. In sites with a sparse under-storey, more repetitions of censuses of short duration were more effective. To obtain a complete species list, a total time of around 100 census minutes was required in sparse sites compared with 150 minutes in dense sites. Birds occurring at high density were not necessarily encountered early in the censusing, probably due to their mobility. Increasing wind strength, time after sunrise and minimum temperature adversely affected the number of species found.

ISSN:0158-4197    

DOI:10.1071/MU9940009

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

SummaryTen breeding pairs of Willie WagtailRhipidura leucophryswere sedentary and territorial (average territory size 0.85 ha) from 16 September-6 December 1990, at the end of the dry season and the beginning of the rainy season, an important part of the Willie Wagtail breeding season in Papua New Guinea. Nine of 15 nests found were built over water; they were 1–14 m above ground or water. Most were cup-shaped, easy to find but difficult to climb to. Both parents built the nest. During laying eggs were incubated 7080% of the time, mostly by the female. Later, the eggs were incubated for 90% of the daytime and female sitting dominance was not so clear. One-day-old nestlings were brooded most of the day; this decreased as the nestlings grew and after day 7 became minimal. During the first three days of nestling life the male shared brooding; his share decreased later. Both parents equally fed the nestlings. Visits with food per hour varied from 5–26, and increased with nestling age. Males and females foraged in the same places, within 1–200 m of the nest, usually not more than 70 m away. Patterns of post-natal growth in the Willie Wagtail are similar to those of other passerines. Eight different hunting techniques were distinguished. Parent birds spent most of their time at the nest which they defended rather than concealed. Peak singing activity was just before sunrise.

ISSN:0158-4197    

DOI:10.1071/MU9940017

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

SummaryRockhopper PenguinEudyptes chrysocomenumbers at Campbell Island have declined by 94% since the early 1940s. Many breeding colonies have disappeared and the remaining nine major colonies have all shrunk in size. We estimate there were 103 000 breeding Rockhopper Penguins in 1985, compared with approximately 1.6 million in 1942. The decline had started by 1945, was greatest during the next ten years and coincided with substantial changes in sea temperatures. The mean December-February sea- surface temperature rose from 9.1°C in 1944 to peaks of 9.7°C in 1948–49 and 9.6°C in 1953–54. It declined to 8.6°C by 1965, rose rapidly to 10.2°C by 1970, and has averaged 9.7°C since then. In one colony, Rockhopper Penguin numbers temporarily increased after the cooler seas in the 1960s. We consider that rising sea temperatures are associated with the decline, which may have been caused by changes in the penguins' food supply; there is no evidence that terrestrial factors have been responsible.

ISSN:0158-4197    

DOI:10.1071/MU9940027

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

SummaryUntil October 1990, the Night Parrot of Australia was known from only 22 specimens, all but one from last century. Despite regular reports, there was no supporting evidence. We found a road-killed specimen near the edge of the species' known distribution. This bird, an adult, possibly male, confirms the continued existence of this species.

ISSN:0158-4197    

DOI:10.1071/MU9940037

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

SummaryAmong the satellite islands of the New Guinea region, the Aru Islands are the largest and have the richest avifauna, yet no comprehensive field observations of Aru Island birds have ever been published. On the basis of visits to all the main Aru Islands and many outliers, we added 16 species to the Aru avifauna. The most significant additions are of seven presumed resident species: the ternSterna albifrons; the pigeonsPtilinopus rivolicf.prasinorrhousandGeopelia striata; cuckoo-shrikeCoracina lineata;and the flycatchersRhipiduracf.phasiana, Microeca flavigasterandM. griseoceps.We describe field observations for little-known species of restricted distribution, including the pigeonsPtilinopus wallaciiandDucula concinna, the kingfisherDacelo tyro, the crowCorvus fuscicapillusand the white-eyeZosterops chloris.We report a distinctive song of the morphologically confusing honeyeater populationMeliphaga gracilis gracilis.At least four of these species (Ptilinopus rivoli, Ducula concinna, Rhipiduracf.phasianaandZosterops chloris)are‘supertramps’confined to outlying Aru islands.

ISSN:0158-4197    

DOI:10.1071/MU9940041

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

SummaryThree species of finch, GouldianErythrura gouldiae, Long-tailedPoephila acuticaudaand MaskedP. personatawere studied at two sites (Newry and Yinberrie) in the Top End of the Northern Territory. The Gouldian Finch began to moult after its breeding season (usually late February-August) at Newry, earlier at Yinberrie. The Long- tailed Finch began to moult during its breeding season (usually early February-October). The rates of moult increased in the order: Long-tailed, Masked and Gouldian Finch. All species began to moult later at Newry, the drier of the two sites. In Gouldian and Masked Finches, both sexes began to moult at the same time. Gouldian Finches were heaviest, while Masked Finches were lightest. Adult weights were lowest during the dry season, May to October.

ISSN:0158-4197    

DOI:10.1071/MU9940046

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9940053

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9940055

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9940058

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor