摘要:

SummaryOlsen, P.D.&Olsen J. (1989). Breeding of the Peregrine FalconFalco peregrinux.II. Weather, nest quality and the timing of egg laying.Emu89, 1–5.Peregrine Falcons near Canberra bred slightly earlier following a dry winter. The laying season was shorter and ended earlier when there were many raindays between June and September. The number of raindays in July and August accounted for 77% of the variation in the length of the laying period. A warm, dry winter was associated with a lengthened laying season. A longer, slightly earlier, laying season resulted in more pairs laying and therefore more young raised by the population. Late-laying pairs were only slightly less successful than early-laying pairs. Pairs with alternative nest(s), or with a well-drained nest, had a longer egg laying season, and more of them laid, than other pairs. Thus, pairs holding a territory with a high quality nest were advantaged over those that were not, because of the direct effect of rain.

ISSN:0158-4197    

DOI:10.1071/MU9890001

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

SummaryOlsen, P.D.&Olsen, J. (1989). Breeding of the Peregrine FalconFalco peregrinus: III. Weather, nest quality and breeding success.Emu89, 6–14.Peregine Falcons laid clutches at 75% of territories annually and fledged young from 58%. Sixty-seven per cent of pairs fledged young each year. Brood size at fledging was 2.16, equivalent to 1.44 young per pair, or 1.23 young per territory. For the population persistent rain and low temperatures in the three to four months between egg laying and to a week or so after hatching had an adverse effect on breeding success; in years when the number of raindays was high fewer pairs bred, more clutches failed to hatch and some very young nestlings may have died. July-September raindays accounted for 60% of the variation in young fledged per territory while mean maximum temperature between August and October accounted for 74% of the variation in the percentage of territories from which young fledged and raindays in those months accounted for 58%. On the other hand, brood size was larger in years when it was wet during the nestling period. Overall, severe drought enhanced the breeding success of the population because more pairs bred successfully. Almost all of the adverse effect of rain could be attributed to nest quality: (1) in cold, wet years Falcons with a choice of nest, or with a well- drained, well-sheltered nest, bred as successfully as they did in dry years, while those without such nests performed poorly; and (2) the average number of young fledged from territories with a choice of nest was about 50% greater than that from territories with only one nest. The advantage of holding a territory with a high quality nest(s) as oppposed to a poorer nest, has clear selective value in the Darwinian sense.

ISSN:0158-4197    

DOI:10.1071/MU9890006

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

SummaryWeimerskirch, H., Zotier, R.&Jouventin, P. (1988). The avifauna of the Kerguelen Islands.Emu89, 15–29.The status of the 35 bird species breeding on the Kerguelen Islands in the south-western Indian Ocean is reviewed in view of recent discoveries and censuses made between 1984 and 1987. Aspects of the breeding biology of most of the species are described, together with weights and measures for 17 species for which data were previously scarce or unavailable. Four new breeding species have been recently discovered on the archipelago: the Yellow-nosed Albatross, the Southern Giant Petrel, the Soft-plumaged Petrel and the Fairy Prion. The population sizes of King and Macaroni Penguins and albatrosses were monitored: the first two species increased in number during the last 20 years, while Wandering and Black-browed Albatrosses decreased. The status of the three prion species is reviewed and the study validates the previously debated specific status of Kerguelen Antarctic and Thin-billed Prions. The taxonomic status of several Kerguelen seabird populations is discussed. Most of the burrowing petrels breeding on the mainland are today threatened by predation from recently introduced feral Cats and by degradation of their habitat caused by introduced Rabbits and other herbivorous mammals. The presence of 300 islands and islets around the mainland, mostly yet unmodified, will ensure the safety of much of the Kerguelen avifauna if they are protected now from further interference.

ISSN:0158-4197    

DOI:10.1071/MU9890015

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

SummaryPyke, G.H., Recher, H.F.&O'Connor, P.J. (1989). Patterns of residency and movement among honeyeaters in heathland near Sydney.Emu89, 30–39.We present patterns of residency and movement derived from the results of a five-year program of banding birds and a three-year program of observing the location and behaviour of individually colour-banded birds in heathland in Brisbane Water National Park, near Sydney. New Holland and White-cheeked Honeyeaters account for most birds captured or observed in our study area. We define a resident bird to be one that is observed nesting and/or is repeatedly sighted in about the same area over a period of at least two days and then categorise species on the basis of whether or not resident individuals are present throughout most of the year. Those species that satisfy the latter criterion also exhibit high recapture rates whereas other species have relatively low recapture rates. We argue that our definitions are more useful than others in the literature. Based on the above definition and on recapture data, most individual New Holland and White-cheeked Honeyeaters are either transients that are captured just once and are never mapped as resident; or occasional residents that are captured more than once, visit our study area throughout their lives but satisfy our definition of resident only some of the time. Future residents, for example, spend some of their time on our grids for an average of eight months before being mapped as residents. There are also gaps of about three to five months between periods of residency. During summer, the residents appear to spend less time in our study areas than during the rest of the year. However, there appears to be no regular, seasonal movement of New Holland and White-cheeked Honeyeaters into and out of our study area. Residents show little variation over time in the locations of their centres of activity in the heathland and do not move far from these areas. Consequently, emigration of resident birds is negligible and departures of residents must be due to mortality. This mortality of residents, which averages about 54% p.a., is associated with low availability of nectar, the principal source of energy to these birds. Individuals often change partners but not unless their partner vanishes, presumed dead.

ISSN:0158-4197    

DOI:10.1071/MU9890030

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

SummaryAmbrose, S.J.&Davies, S.J.J.F. (1989). The social organisation of the White-browed ScrubwrenSericornis frontalisGould (Acanthizidae) in arid, semi-arid and mesic environments of Western Australia.Emu89, 40–46.The social organisation and demography of White-browed ScrubwrensSericornis frontaliswere studied in arid, semi-arid and mesic environments of Western Australia over three years. The highest incidence of co-operative breeding was observed in the semi-arid environment whereas it was least common in the arid environment. Social grouping was also a common occurrence in the mesic environment, but only a small proportion of these groups bred co-operatively. Auxiliary (non-helping) membership in the groups seems to be due to habitat saturation resulting from a high survival rate of birds in the population. Helpers contribute significantly to the feeding of nestlings and the maintenance of nest hygiene and, on average, cooperatively-reared nestlings fledge one to two days earlier than those reared by parents only. This shortened nestling period increases the probability of young fledging before the onset of unfavourable environmental conditions. The low incidence of co-operative breeding in the arid environment seems to be due to the slight competition for breeding space as a consequence of a high mortality rate amongst immature and adult birds. This high mortality rate may be due to the inability of birds to cope with harsh summer conditions after the depletion of body reserves resulting from recent breeding attempts.

ISSN:0158-4197    

DOI:10.1071/MU9890040

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

SummaryCrome, F.H.J.&Moore, L.A. (1989). Display site constancy of bowerbirds and the effects of logging on Mt. Windsor Tableland, north Queensland.Emu89, 47–52.The localities of display sites of Tooth-billed Catbirds, Golden and Satin Bowerbirds were mapped for four successive years in two adjoining areas of upland rainforest on the Mt. Windsor Tableland, north Queensland. One of the areas was logged halfway through this period. Most display sites were located along ridges and logging reduced the number of courts of Tooth-billed Catbirds on the logged area by 33% but the same number of courts were built concomitantly on the adjoining unlogged area. The latter resulted in no extra crowding as measured by distance to nearest neighbour. Most sites for courts were used from season to season and recaptures of banded birds showed that some were caught in the same site from year to year. Management of road and track construction and maintenance in rainforests is discussed in relation to bowerbird conservation. It is recommended that clearing of roadside vegetation be kept to a minimum where roads follow ridges.

ISSN:0158-4197    

DOI:10.1071/MU9890047

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9890053

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9890055

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9890058

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0158-4197    

DOI:10.1071/MU9890061

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor