摘要:

SummarySome aspects of the weights of over 5,500 birds of 79 species, mostly migrants, captured in spring at an oasis on the northern edge of the Sahara, are discussed. Mean weights for five species were 26–44% below those of fat birds (those containing at least 30% lipid) weighed about the same time on the south side of the desert. Weights of fresh arrivals in Britain are higher than those in North Africa, but the differences are not great, suggesting that these have also made a long journey across Europe. Peak arrival times of day‐migrants differed from those of night‐migrants and the weights of some species varied with the time of day. There was no great advantage to migrants in remaining at the oasis; there were few weight changes greater than those normally occurring within an individual's daily range. Several species lost weight steadily during a cold spell, and many died. Male Swallows are heavier and larger than females, and in both sexes weight increases with wing

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01598.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryAt normal outdoor temperatures there is a distinct influence of brood size on the heat production of ten‐day‐old Great Tits. One ten‐day‐old nestling proved unable to maintain its body temperature at 12°C. Two ten‐day‐old tits together in one nestbox at 12Á°C were able to elevate the air temperature sufficiently to maintain homoiothermia. The same of course holds for tits in larger broods.At an air temperature of 18°C, six or seven ten‐day‐old tits placed in a nestbox elevated the air temperature to a level at which they almost reached a state of hyperthermia: their metabolism was at the basal level. The basal metabolism of a ten‐day‐old tit was found to be slightly more than 0–1800 kcal/h. The metabolism intensity of 12 tits in a nestbox at 12°C was of the same order of magnitude.Tits in broods comprising more than 12 or 13 nestlings at normal outdoor temperatures probably develop hyperthermia, which is unfavourable both for their energy a

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01599.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryThis paper sets out the results of fairly regular observation ofOreotrochilus chimborazoon Mt Cotopaxi between 1964 and 1967.The species is found between 13,000 and 15,000 ft in a small area just south of the Equator where it nests on cliffs. Climate, terrain, food and nesting are described. Breeding continues throughout the year. Particular attention is given to the importance of nesting sites in this harsh climate and the consequent tendency towards colonial* nesting in favoured spots. The high degree of segregation between the sexes is also considered.A brief account is given of theO. chimborazopopulation in the Guamani pass on the rim of the Amazon basin, where climate and terrain have produced some differences in breeding habits.

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01600.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryThe manner in which bee‐eaters cope with the stinging honey‐bees which comprise their principal food was investigated by aviary studies ofMerops bullocki.WorkerApisare de‐venomed by an innate sequence of beating the insect and rubbing its abdomen against the perch. Treatment improves with experience. Drone bees are distinguished by the birds from workers but are not instantly recognised as non‐venomous; they are subjected to low intensity rubbing combined with non‐venomous prey treatment concomitant with their size. Non‐Hymenoptera, including some insects which superficially resemble bees, are recognised as non‐venomous and are not rubbed, but are beaten until immobilized. Bee‐eaters appear to have partial im

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01601.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryLava GullsLarus fuliginosuslive as scavengers and unspecialized predators along the shores of the Galapagos Islands. Although they concentrate locally at places where refuse is available, their breeding density is low: eight breeding pairs were found along a stretch of 35 miles of the coast of Indefatigable Island. The total (world) population is likely to be less than 300–400 breeding pairs.Their low breeding density and small total population is attributed to the fact that they are confined to linear feeding grounds of limited extent, which provide a sparse food supply for much of the year.Lava Gulls nest solitarily, usually in sheltered places near coastal lagoons; all the nests found were at least two miles from any other known site. The clutch consists of two eggs, incubation (one case) lasts 32–33 days, and the fledging period is about 60 days.Breeding takes place throughout the year, with no apparent peak. Individual cycles of 9–12 months have been recorded.Observations are given on behaviour and displays, and on the sequence of plumage change and moult in the first two years of

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01602.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryDiet, feeding frequency and body temperatures were studied in nestling House Sparrows at Oxford. In the diet, studied principally from crop contents, dipterous flies, caterpillars and aphids were most prominent in early May, early June and July respectively, while bread and dry grain, apparently less suitable foods, were more evenly distributed throughout the breeding season but apparently acquired an importance when insect foods were scarce.Adult House Sparrows increased the frequency of their feeding visits to the nestlings proportionately with brood‐size for broods of 1–3, but for larger broods the feeding frequency did not increase. This abruptly achieved upper limit presumably gave rise to inadequate feeding of the larger broods (including the principal brood‐size). The male's share of the visits decreased markedly in the later stages of the nestling period, corresponding to his initiation of a display directed at the female. His displaying at this stage probably allows the female to begin a further clutch soon after the previous nesting has finished.Nestlings were unable to maintain a steady body temperature above the ambient air temperature outside the nest before nestling day 10½. Maintenance of a steady body temperature depends on the nestling's feather covering, which is effectively complete at 9½ days. Before this, temperature control is possible within a limited range of ambient tempe

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01603.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryAn account is given of the migration of British summer resident small passerine night migrants across the English Channel in spring and autumn, as detected by radar.The main times of passage of each species have been determined from the trapping records of Dungeness Bird Observatory.The tracks of the migrants are consistent with the view that they always head about NNW in spring and SSE in autumn but may be drifted by a cross‐wind.The wind‐direction and speed had a paramount influence on the volume of migration in both spring and autumn. Temperature had no effect in autumn, and though there was more migration with warmer than cold weather in spring, this need not have been due to the influence of temperature as such.Small reversed movements occurred, with southerly winds in autumn or, more doubtfully, with northerly winds in spr

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01604.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryNo agreement has been reached on the classification of the avian order Gruiformes as defined by Peters (1934) and Wetmore (1960). Starch gel electrophoresis of egg white proteins was therefore carried out in an attempt to obtain additional taxonomic data. Individual and intrafamilial variability was observed to be small, and the protein patterns thus seem to provide a basis for classification above the familial level.These protein patterns, together with the historically conventional characters, suggest that a relationship exists between the Rallidae, Heliornithidae, Eurypygidae, Turnicidae, and Psophiidae; and that the Gruidae and Aramidae are not far removed from this assemblage. The Aramidae are thoughttooccupy a separate but intermediate position between the Gruidae and the rail‐like assemblage. The Otididae have a very different pattern which, together with the unusual combination of classical characters, suggests that the bustards should be removed from the order. The insufficient sampling from the Cariamidae and Rhynochetidae does little to clarify their systematic position

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01605.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01606.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1969.tb01607.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY