摘要:

SummaryParameters used to characterize the course of growth are described, and calculated growth parameters are presented for 105 species of birds of many taxonomic groups from a wide range of geographical localities.Growth parameters are found to exhibit as much as 20% variation within a species with respect to geographic locality and time of the nesting season. There is also considerable local variation, irrespective of season and locality, which is related to nutrition and perhaps to an inherited variability. The application of curve‐fitting as a method of analysing intraspecific variation is discussed briefly, and the importance of comparative growth studies is emphasized.Growth patterns are correlated with other parameters of the life‐history to evaluate the extent of diversity in the course of growth. Low rates of growth and prolonged growth periods occur primarily in species large for their families and in oceanic species. In most others, high rates of growth are maintained for longer periods of time. The shape of the growth curve is not related to the mode of development (i.e. whether precocial or altricial).Overall relative, or weight‐specific growth rates, as measured by the constants of fitted growth equations, are most highly correlated with the adult body size of the species, changing as the ‐0–278 power of adult body weight. Smaller variations in the rate of growth appear to be correlated with differences in nesting success; open‐nesting passerines grow faster than hole‐nesting species of a similar size. Growth rate is further correlated with brood size. Oceanic species with single egg clutches and tropical land‐birds with small clutches have low growth rates.The asymptote of the growth curve of the young (in relation to the adult weight) is related to the foraging behaviour of the adults. Aerial feeders generally have high asymptotes while those of ground feeding species are usually below adult weight. These differences are related to the need in the former for well‐developed flight at the time of fledging.The diversity of growth patterns is related to evolutionary trends which are the result of (1) selective forces acting at stages of the life‐history cycle other than development, (2) factors which affect the survival of offspring during the growth period, and (3) adjustments made to balance the energy budget of the family group. The last trend is discussed in detail in relation to the correlations found in the analysis. Two hypotheses are presented. Firstly, in species which cannot gather enough food to support even one young at a normal growth rate, the pace of development is reduced to decrease the energetic requirements of the young. Secondly, in species with small clutches, where adjustments to feeding capacities are not readily made by changing brood size, growth rate may be adjusted to accomplish this. The lack of critical energetic data to test these hypotheses is emphasized as a major deficiency in our understanding of the breedi

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00058.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SummaryVery few quantitative data existed for the spring migration of birds across the Sahara desert. Observations covering 105 days in spring 1963–66 were made at Defilia, on the extreme northern fringe of the desert in southeast Morocco. The physical features and climate of the area are described, with brief reference to neighbouring desert zones. The birds recorded are listed in weekly or part‐weekly totals, followed by subspecific and other comments on selected species.The movements of migrants are summarized, together with the effects of adverse winds on migration; very bad weather along the northern desert fringe may contribute to the late arrival of some species in the British Isles (and presumably elsewhere in Europe) in spring by causing delays and heavy mortality. Most visible migration was northeastward or eastward, but substantial westward movements of hirundines took place.Comparison is made with migration through other areas in Morocco and Algeria, both from existing literature and from previously unpublished data, which provide evidence of broad‐front migration across the entire width of the Moroccan Sahara. Birds recorded in northwest Algeria in 1966 are listed, together with notes on physical features, climate and field observations. Many terns and waders were recorded at Daiat Tchiour, including some predominantly coastal species, which suggests that the latter were migrating on a great‐circle track from winter quarters in West Africa across the Sahara to their breeding grounds in Siberia.Recoveries of ringed birds are discussed; some of these, together with records of species well west of their normal migratory range, suggest that birds may be subject to lateral displacement by winds when crossing the Sahara, leading to considerable annual variation in species and numbers of birds recorded on the northern desert edge, even in the sam

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00059.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SummaryThe present paper summarises observations made during the International Indian Ocean Expedition on board the R.R.S.' Discovery, from August to November 1963 and from February to September 1964 in the Indian Ocean north of 20° S and west of 70° E. In 1963 work was carried out in the Somali Basin. In 1964 a series of transects were made over the ocean, the main purpose of which was to investigate the system of equatorial currents and the changes in the sea associated with the onset of the Southwest Monsoon in May.The Tropical Indian Ocean is briefly described. Except for local concentrations, the surface layers are poor in nutrient salts and plankton. There is a seasonal reversal of winds and surface currents in the Arabian Sea, but seasonal changes become less marked further south.Previous ornithological observations in the western Indian Ocean are mostly confined to the Arabian Sea or to the island groups. Thus, existing information on the pelagic range of pantropical species is incomplete.Observations made on each transect across the Indian Ocean in 1964 are summarised and compared with oceanographic data collected at the same time. General conclusions are not possible on the basis of so little information, though there appeared to be some relationship between the distribution of certain species and wind or current belts. The only marked discontinuity recorded was a concentration ofPuffinus pacificusandGygis albaat the northern edge of the Equatorial Counter‐current at 58° E in March. Observations made on transects that were repeated before and after the onset of the Southwest Monsoon suggested thatSterna fuscataconcentrates in the equatorial region as the monsoon develops. In general, both plankton and sea‐birds were more abundant at 58° E than at 671/4° E.An analysis of the presence or absence of sea‐birds during each observation period, which lasted an average of one hour, established the difference between pelagic species and those largely restricted to within 50 miles of their breeding stations. There was no evidence of any correlation with zooplankton abundance, though birds of all species taken together were commonest where flying‐fish were most abundant andS. fuscataappeared to be commonest in cool‐water areas with strong winds, i.e. the Trade‐wind belts. It was not possible to sample the food organisms of sea‐birds quantitatively.Sea‐bird observations in the Indian Ocean more than 200 miles from the continental coasts are summarized and compared with previous observations.The little information collected in the Indian Ocean agrees with previous work in the Pacific Ocean, where sea‐birds are commonest in areas of convergence, and not where local upwelling and an associated concentration of plankton occur, such as on the equator. This may be due to the fact that populations of organisms on which sea‐birds feed develop or concentrate a considerable time after upwelling of nutrient‐rich water occurs.Since few sea‐birds were seen feeding, it seems likely that available food is scarce and that much time is required to locate areas where it is abundant.Finally, evidence is presented to indicate how some sea‐bird species may avoid or reduce competition by feeding at different distances offshore, or i

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00060.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SummaryThe migration of soaring birds was observed at Küçük Çamlica at the southern end of the Bosphorus between 14 July and 8 November 1966. Simultaneous watches were also carried out at other points on the Bosphorus on a number of dates. The largest movements of birds of prey occurred on days of light northeasterly winds, the largest movements of storks on days of light winds with a southerly component. On most days the stream of migrants appeared to be concentrated over the southern end of the Bosphorus. Migration frequently occurred right throughout the day, though the peak period was usually not spread over more than three hours. Figures are given for the daily times of migration of the commonest soaring birds. Daily counts of soaring birds (storks, raptors and Cranes) migrating over the Bosphorus at Küçük Çamlica are given. The main species found migrating were (with total number recorded in brackets) White StorkCiconia ciconia(207,145), Black StorkC. nigra(6,194), Honey BuzzardPernis upivorus(8,997), BuzzardButeo buteo(12,949), “Spotted” EagleAquila clanga/pomarina(4,309) and sparrowhawkAccipiter nisus/brevipes(5,224). The autumn migration of 1966 is discussed in detail in a systematic list. BuzzardsB. buteowere recorded in large numbers for the first time at the Bosphorus, and were the commonest bird of prey. CranesGrus gruswere also recorded for the first time. Comparison is made between our results and those of previous workers, though differences of coverage rule out any firm

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00061.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00062.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SummaryThe present paper describes the results of experiments designed to evaluate the importance of auditory‐motor experience in the development of song in the Chaffinch. For this purpose a number of Chaffinches collected as nestlings or adults were deafened by extirpating the cochlea at different ages. Recordings of their song made subsequently provide the material on which the paper is based.Since the results of the experiments can only be interpreted in the light of knowledge of normal song development, the latter is described from the observation of previous workers and from some new material.Of the 20 males deafened, only three came into full song of their own accord; song was induced in the rest by the administration of testosterone phenylacetate or testosterone propionate. Songs of abnormal length were common among first‐year males though males deafened when two or more years old produced song of the normal length. The song of male Chaffinches deafened as adults, that is after they had produced full song for one or more breeding seasons, was infistinguishable from that produced by intact adult males. They even went through a “plastic” song stage in which some “intermediate” themes occurred. A first‐year male deafened when it had almost stabilized its song produced song that gradually deviated more and more from normal song. This indicates that the bird had not yet laid down a long‐term memory of its song independent of auditory feedback.First‐year male Chaffinches deafened during early spring, mid‐winter and late sumer, respectively, show that the more they were deprived of the normal period of auditory‐motor experience, the simpler was the song they produced in their first spring. Thus, at the time of deafening they had acquired a particular auditory‐motor experience, and it is the type of element established up to that time that is incorporated into full song.Male chaffinches brought into the laboratory as nestlings and deafened when three months old produced a virtually sfyctureless song, in which the only recognizable element was a sound reminiscent of the juvenile “chirrup”. The subsong and other calls of these birds were also highly abnormal. Song development in the Chaffinch clearly starts before song as such has made its appearance.The available evidence suggests that the kind of song a male Chaffinch produces depends directly on its auditory‐motor experience before deafening. There is no indication that deafening achieves its effects on the resultant song by interfering with the hormonal substrate.Relatively stable song end patterns develop in the absence of auditory feedback, so their occurrence does not necessitate the postulation of templates or preconceived patterns. Song development differs mar

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00063.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00064.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00065.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00066.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1968.tb00067.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY