ISSN:0158-4197    

DOI:10.1071/MU9910001

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummaryGeographic variation in the Zebra FinchTaenio-pygia guttatawas examined by comparing live wild-caught and captiveT. g. guttatafrom the Lesser Sunda Islands in Indonesia andT. g. castanotisfrom the Australian mainland and confirmed by museum skin measurements ofguttataandcastanotis.(1)T. g. castanotisis significantly larger thanT. g. guttata, as measured by wing length, weight and bill length. (2)castanotishave redder, darker, brighter bills thanT. g. guttata.(3)T. g. castanotismales have larger breast-bands thanT. g. guttatamales, even when the size difference is taken into account, with strongly pronounced black barring on the throat and upper breast which are absent fromT. g. guttatamales on Lombok, Sumbawa, Flores and Timor. (4)T. g. castanotisproduce lower frequency distance calls and the males differ fromT. g. guttatamales in having a noise part to this call. (5) The songs of captiveT. g. castanotismales are lower in frequency and their song phrases are shorter, with fewer elements per phrase, than captiveT. g. guttatamales from Timor. In contrast to the differences betweenT. g. castanotisandT. g. guttata, little geographic variation was found withinT. g. guttataon the four islands studied, although there was a cline of decreasing size in bill depth from west (Lombok) to east (Timor). The status of the two forms,T. g. guttataandT. g. castanotis, is discussed.

ISSN:0158-4197    

DOI:10.1071/MU9910002

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummaryMorphological differences between the sexes in KeasNestor notabiliswere quantified from a sample of 86 sexed museum specimens, nine sexed zoo captives and 129 live, wild-caught birds. The results demonstrate that Kea are sexually dimorphic. Males are about 5% larger than females in linear measurements of body size and their upper bills are on average 12–14% longer, with a slightly larger radius of curvature. The dimorphism in bill size was statistically independent of the difference in overall body size, suggesting the possibility of intersexual differences in niche utilisation. Culmen length appears to be a useful means for distinguishing sexes in the field: our data indicate an optimum separation criterion of 43.9 mm for wild-caught individuals. Culmen length measurements from specimens originating in captivity were more variable. There was no evidence that sexual dimorphism increases with sexual maturity in this species.

ISSN:0158-4197    

DOI:10.1071/MU9910012

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummaryThe problem of establishing the breeding status of burrowing birds is compounded by the inaccessibility of long meandering burrows. A solution, involving manipulation of a mini video camera and monitor, using infra-red light is presented which enables efficient, reliable recording of burrow occupancy with minimum disturbance to the birds and burrows. It was designed to establish the breeding status of the Wedge-tailed ShearwaterPuffinus pacificusin the Capricorn Group of islands, Great Barrier Reef, but with proper screening and possibly, further modification, its use need not be site or species specific.

ISSN:0158-4197    

DOI:10.1071/MU9910020

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummaryThe precocial Magpie GooseAnseranas semipalmatanests colonially on seasonally inundated floodplains, producing a large conspicuous nest. As predicted from the hypotheses of Rohwer&Freeman (1989) regarding the ecological correlates of intraspecific nest parasitism, nests are parasitised by conspecifics. Criteria based on laying rates and sequences classed 35% (n= 22) of closely monitored nests (n= 63) as parasitised. Criteria were conservative, but interpretation is complicated by variable mating arrangements including a preponderance of trios comprising one male and two females. Parasitism rates may have been increased by rising water levels which resulted in flooding of most nests after about one third of the incubation period. Mean clutch size in nests classified as parasitised (10.9±2.3 [s.d.]) was significantly greater than apparently unparasitised nests (8.5±3.1). Parasitic eggs were similar in size and shape to other eggs in parasitised clutches. Clutch size, within-clutch variation in egg dimensions and degree of staining are unlikely to identify parasitism reliably. Improved assessment of the incidence and ecological importance of intra-specific nest parasitism in the Magpie Goose requires further study employing a combination of biochemical and observational techniques.

ISSN:0158-4197    

DOI:10.1071/MU9910026

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummaryOn Penguin Island, Western Australia, similar numbers of Little PenguinsEudyptula minorcame ashore at each of the three landfall points on beaches giving access to the main breeding area. Almost every marked bird consistently used only one of these landfall points, and nested close to this point, but the same individuals did not regularly come ashore together. Little Penguins first arrived on the island 0.5–1 h after sunset throughout 1986–87, in groups of about ten. Peak arrivals occurred about 1–2 h after sunset and peak departures around sunrise. Arrival times and group sizes did not appear related to climatic conditions. The strict nocturnality of Little Penguins may be related to the avoidance of predators, human disturbance and heat stress, or to daylight feeding at sea. The small size and isolation of the Penguin Island colony do not favour its development as a tourist spectacle.

ISSN:0158-4197    

DOI:10.1071/MU9910032

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummaryPlayback experiments and an investigation of song interaction were used to examine the response of SilvereyesZosterops lateralis chlorocephalato the individual variation in their territorial song. The Silvereyes did not respond differentially to playback of neighbours' or strangers' songs, nor did they habituate to the presence of playback song within or between experiments. The continuous nature of the individual variation in the Silvereyes' songs did not allow their perception of specific individuals or groups on the basis of song structure. Time of day, the individual's song used and the age of the individual responding did not significantly affect the response. There was no apparent interaction of song between territorial males, either in acoustic avoidance or song stimulation.

ISSN:0158-4197    

DOI:10.1071/MU9910036

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummarySkins of ibises attributed to forms within the Sacred IbisThreskiornis aethiopicuscomplex,sensuHolyoak (1970) were examined for variation in 12 morphological characters and measured for four other characters. This investigation revealed significant variation within these characters and that several forms of the ibis showed distinct and diagnostic suites of characters. The study concludes that three species should be recognisedviz. T. aethiopicus, T. melanocephalusandT. moluccuscomprising a superspecies complex. It was also concluded thatT. strictipennisis synonymous withT. moluccusand thatT. pygmaeusis a distinct and dwarfed form ofT. moluccus.The formsT. abbottiandT. bernieriare very similar to one another and are most closely related toT. aethiopicus. T. melanocephalusis distinct from other members of the complex.

ISSN:0158-4197    

DOI:10.1071/MU9910041

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

SummaryThe conservation status, with special reference to nesting requirements, of the Red-tailed Black-CockatooCalyptorhynchus banksii graptogynein south-eastern Australia (specifically, south-western Victoria) was studied between December 1988 and April 1990. Though the total population size is uncertain, it seems that the subspecies numbers between 500 and 1000 birds with considerably fewer than 200 birds breeding. For feeding, nesting and roosting the birds use three distinct habitats each of which has declined and continues to be under some threat. Twenty-five nests were found in 22 hollows in 21 trees. Seventeen nests were in dead trees and we have stressed the apparent importance of dead trees to the birds' conservation needs.C. b. graptogyneis clearly endangered and in need of more detailed and long-term study of its ecology and demography.

ISSN:0158-4197    

DOI:10.1071/MU9910046

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9910051

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor