摘要:

SUMMARYFifty species of insectivorous warblers Sylviidae, flycatchers Muscicapidae and whistlers Pachycephalidae were studied in primary rainforest at various localities in New Guinea. The structure of the various forest types is described and the birds' feeding ecology and behaviour analysed by recognizing three main foraging techniques and five horizontal and three vertical basic structural divisions of the habitats.Altitudinal ranges of the species are assessed to determine potential co‐existence and they are divided into lowland and lower montane groups (either side of the main avifaunal discontinuity at 1500 m) with a third small group occurring in both areas and a fourth group of 12 lower montane species that occur also in the structurally much simpler Upper Montane forest.The feeding behaviour and ecology of the species within each major habitat are compared, with particular attention to taxonomically related and ecologically similar species. Other important considerations—additional behavioural differences, notable morphological distinctions, altitudinal separation of ranges within the habitat—are also noted.The likely importance of differences in foraging behaviour and feeding sites for reducing competition between related species is amply demonstrated, members of several pairs and groups of species have nearly mutually exclusive preferences. The overall pattern of habitat utilization is, however, extremely complex with nearly all stations used, in a variety of ways, by several species and there are many instances of substantial similarity between pairs of species, often involving congeners.The calculation of information theory derived indices of foraging diversity and overlap enables more general comparisons between the altitudinally graded habitats to be made and differences related to current ideas on tropical species diversity.Between Lowland and Lower Montane forest there is a fairly general trend of reduction in foraging diversity and decrease in the mean overlap between species in many genera and groups. The 12 species that continue into the simpler Upper Montane forest show very significantly reduced foraging diversity (compared with their values in lower montane forest) and also less overlap, indicating a different relationship between these species in the absence of the other Lower Montane forest birds. Together these results suggest that the most tropical (i.e., lowland) species show greatest overlap but do not necessarily have smaller niches.In progressively higher habitats there is a bias to the disappearance of generalist (high diversity index) species. These mainly use flycatcher‐gleaning techniques supporting suggestions that the increase in insectivorous species in the tropics is partly due to exploitation of feeding strategies related to hovering. Habitat and ecological factors influencing this are assessed.The importance of altitudinal isolating mechanisms is also discussed and, amongst the species studied, both on average and in specific cases, those with the greatest similarities in foraging behaviour and ecology are segregated altitudinally and do not co‐exist. It is suggested, however, that substantial overlap between many co‐existing tropical species may not be abnormal, but rather an adaptation for ensuring maximum efficiency of habitat utilization in the prevailing environmental conditions of tropical

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03532.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYThe differential development of various body organs and of fat, water, and other constituents was studied in three species with altricial nestlings—Blue Tit, House Martin and House Sparrow.In all species resources available at each stage of the nestling period were allocated to those components of most use to the nestlings at the time, although due regard was paid to future needs. Components associated with the ingestion and assimilation of food, such as the mouth, gizzard, intestine and liver, developed early in the nestling period whilst locomotory components, such as wings and pectoral muscles, developed late. Similarly, body plumage needed for insulation developed ahead of the locomotory remiges and rectrices, but only after much of the nestlings' growth in size had been completed.The water index (water content/lean dry weight) provided a consistent index of tissue and nestling maturity amongst young of different nutritional status. This index was very similar for all three species when age was expressed as a fraction of the nestling period.Both absolute fat content and the fat index (fat content/lean dry weight) increased with age. The adaptive value of these trends and of interspecific differences in fat index is discussed.The results are seen as consistent with both the physiological bottleneck models of avian growth rates. It is suggested that the growth patterns of birds may be dominated more by ecological considerations affecting all aspects of the development mode than by internal physiological constraints affecting growth rates alon

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03533.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYThe bowing display and other postures commonly seen in sexual display, of Australian and some New Guinea pigeons are described. These behavioural data are examined to determine how they support phylogenetic groupings based on the birds' morphology.The inclusion ofLeucotreronandMegaloprepiainPtilinopusis supported. Among the bronzewing pigeonsPhaps, Ocyphaps, GeophapsandPetrophassaare very similar behaviourally, as well as morphologically;Petrophassais the most divergent. The display postures do not assist the classification ofLopholaimus, ChalcophapsorLeucosarciabut, rather, emphasize the separation of these from other groups of pigeon species. The bowing displays ofGeopeliaandStreptopeliado not support the suggestion thatG. humeralisshould be moved from the former genus to the latter.

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03534.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYThe parasitic behaviour of Black‐headed Gulls in a mixed colony of terns and gulls at the Sands of Forvie on the northeast coast of Scotland is described in some detail. Food‐stealing occurred with varying frequency throughout the breeding season. Less than 6% of the terns were attacked during incubation and when their chicks were a few days old, but up to 29% were attacked thereafter. At the same time the percentage of successful attacks rose from 1% or less to 6.5%.Food items brought back to the ternery were predominantly sandeels, clupeids and gadoids. Only a small proportion of terns carrying fish shorter than 7 cm were attacked whether they were sandeels, clupeids or gadoids.Robbing success was higher with clupeids and gadoids than with sandeels.The effect of the Black‐headed Gulls' kleptoparasitism on the Sandwich Terns' breeding success is thought to have been negligible during incubation and early chick‐life, but might have influenced fledging weight and ultimately post‐fledging

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03535.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03536.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03537.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

In Willow GrouseLagopus I. lagopus, as in the otherLagopusspecies, the hen alone incubates the eggs, leaving the nest only to defaecate and feed. The cock stands nearby to defend the nest area against predators and normally takes no direct part in egg or chick care (Johnsgard 1973, Watson&Jenkins 1964). This note discusses two cases of abnormal incubation and chick care by captive Willow Grouse cocks at the University of Tromsø's Wildlife Research Station

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03538.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03539.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03540.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1977.tb03541.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY