摘要:

SummaryExperiments were made using models to analyse the stimuli evoking the pecking behaviour of young Arctic Terns, with comparative tests on Herring Gulls in one year. Some of the findings for the Arctic Tern may be summarized as follows. The chicks pecked at red, blue and silver more than at orange, yellow, green, black and white, and the response was increased by adding a contrasting spot to a beak. A plain red beak, the natural colour in the breeding season, was pecked less than one tipped with black, the colour in the winter. Chicks responded more to the beak models when a “fish” was attached (Fig. 1). Under natural conditions the chicks swallow their food, chiefly the sandeelAmmodytes, head first, and this is facilitated by the chicks pecking more at the head than the tail end of the fish. The stimuli by which head and tail are distinguished were found to be the pattern of the eye and tail‐fin rather than the shape of head and tail.The view that the selectiveness of the tern chicks is adapted specifically to the feeding situation is discussed critically, using the comparative results from the Herring Gull tests, and it is argued that while this is not the case for some of the stimuli effective in evoking the pecking (e.g. movement), whose adaptive significance concerns the general efficiency of the eye, it could well be responsible for some of the selectiveness found (e.g. high response to blue, low response to tail‐fin patterns). Comparison of the two species suggests that the Arctic Tern is specially adapted to respond to fish‐like objects attached to the beak. In the Herring Gull the ability to distinguish the head and tail of a fish appears to anticipate the time when the chick re

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03693.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryThe feeding‐sites of Woodpigeon, Stock Dove and Turtle Dove were examined in a study area in Cambridgeshire by making repeated standardized observations over five years. The crop contents of 614 Woodpigeons and 166 Stock Doves shot throughout the period were analysed to determine the birds' diet. Seasonal variations are detailed. The crop contents of 41 Turtle Doves, and the nestlings of 14 Stock Doves and 5 Turtle Doves were also analysed.During the winter, Woodpigeons fed primarily on clover leaves which they collected from leys and pastures, but also on weed leaves and, during periods of snow, those of various cultivated brassicae. Grain was taken from the spring cereal sowings, after which the birds reverted to clover feeding, supplementing this diet with tree leaf and flower buds. When cereals ripened these comprised the main food being collected from July to November, at first from standing crops and then from stubbles. Wheat was preferred to barley. In the autumn, beech nuts, acorns and other tree fruits were taken and when stocks of these and the cereals were exhausted the birds turned again to clover feeding. Weed seeds, especially pasture species, were collected especially in May and June but only in small amounts.Stock Doves fed primarily on weed seeds throughout the year, obtaining these from fallow ground, ploughed fields and cereal stubbles. Cereal seed was taken when available, but featured less in its diet than that of the Woodpigeon. The most important weed seeds wereSinapsisandBrassicaspecies,Stellaria mediacapsules andPolygonumandChenapodiumspecies. Leaves or tree buds and fruits were not an important food item.Turtle Doves fed primarily on the seeds ofFumariaand grass species, but they also collected cereal grains andStellaria mediacapsules. They collected their food from waste ground or from tall, standing hay or corn crops, where many weeds were growing. They did not appear to feed from trees or hedgerows.The food of nestling Stock and Turtle Doves was similar to that collected by the adults for themselves.The feeding habits of the other British columbids is briefly reviewed. It appears that the Turtle Dove, Stock Dove and Woodpigeon, and also the feral pigeon and Collared Dove occupy different ecological niches, the first three associated with arable farmland. The Woodpigeon, Stock Dove and Turtle Dove have all increased in numbers and range following the development of agriculture. It is likely that the Rock Dove competes for food with the Stock Dove and possibly at times with the Woodpigeon, which probably explains the declining status of the Rock Dove in Britain.The distribution of the Turtle Dove in Britain is similar to the distribution of Fumitory, its major food plan

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03694.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryWet ducklings, like wet chicks, had lower body temperatures than dry birds. The temperature depressions of the chicks decreased as they grew older. The temperature depressions of the ducklings were mainly dependent on the waterproofing of their plumage and how much of their skin became wetted. Completely waterproof ducklings, which maintained a layer of air between their skin and the water, lost heat slowly, but poorly waterproofed birds with wet skins lost heat quickly. Waterproofing was reduced in the laboratory when the ducklings' feathers became soiled and disarranged and when one swam in soapy water.

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03695.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummarySome aspects of the taxonomy and relationships of the barbets are discussed and illustrated, with special reference to the recent classifications of the family by Ripley and by Peters. The colour pattern of the head appears to function as a species‐specific recognition mark. Sympatric species of similar size usually differ strikingly in head colouration. There are several examples of apparent character displacement. The genusPsilopogonis considered to be closely allied toMegalaima. Megalaima lagrandieriforms a link between the two genera. The resemblances betweenCalorhamphusandGymnobuccoare due to convergence. The latter genus is very closely related to the species placed inStactolaema. Lybius chapliniis thought to be closer toL. rubrifaciesthan toL. leucocephalus.The mobility of the rictal bristles of a livingMegalaima asiaticais describe

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03696.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryThe main types of habitat to be found in the Ibadan area are briefly described and their interrelationships considered. The relative degree of shade and cover afforded by each is discussed in relation to human influences.The avifauna, comprising 266 species so far identified in the area, is classified as comprising forest, savanna, widespread and aquatic forms. The status and frequency of each species is indicated.It is shown that the terrestrial element in the Ibadan avifauna is very evenly balanced between forest and savanna forms.The ability of forest forms to emerge from the forest and occupy less shaded habitats is contrasted with the converse ability of savanna forms to enter forested habitats.A number of species are separately noted in a supplement to Appendix 1 that show points of interest concerning their taxonomy, status or range.

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03697.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03698.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03699.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03700.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03701.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03702.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY