ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1927.tb02175.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1927.tb02176.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1927.tb02177.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1927.tb02178.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1927.tb02179.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

摘要:

SUMMARY.1Heinroth's important data on the body‐weight and egg‐weight of 432 species of birds have been re‐examined, and the figures for ten selected groups, and for the total of all groups, presented in simplified graphic form. The body‐weights range from about 2 g. to 90 kg., the egg‐weights from about 0.3 g. to over 1 kg. The relative egg‐weight decreases from 12.2 per cent. in the first class to 1.8 per cent. in that of highest body‐weight.2As already shown by Eeinroth, relative egg‐weight decreases as absolute body‐weight decreases.3The relation between egg‐weight (y) and body‐weight (x) within any group of birds can apparently be expressed by an equation of the form y = bxk. However, while k approximates to 1.0 for small values of x, it gradually decreases with increasing body‐weight, and the limiting value for large values of x appears to be about2/3.4This may indicate that two antagonistic processes are at work in deciding relative egg‐size, one (possibly biological advantage in the struggle for existence) favouring growth of egg‐weight in linear proportion to body‐weight; the other (possibly the physiological difficulty of increasing the bulk of the already enormous egg‐cell) restricting growth of egg‐weight to a linear proportion to surface (of body or egg).5As is well known, different groups of birds show different relative egg‐weights. It is shown that the difference between groups in this respect remains approximately constant through the whole range of body‐size. Special conditions of life, such as nidicolous and naked condition of young (e.g. Oscines), and, still more notably, reproductive parasitism on smaller species (some cuckoos) are correlated with special values for the relative egg‐weight.6The curves for each group are on the whole similar in shape whether the group comprises only small or only large forms. Thus between the same absolute body‐weights, egg‐weight increases much less rapidly in the larger members of a group of low mean size than in the smaller members of a group of high mean size (e.g. OscinesversusColumbæ; Oscines, Columbæ and LimicolæversusAnseres and Otidids).7There are indications in some groups of the superposition of two (or more ?) curves of the above mentioned type, one for the smaller, the other for the larger forms within the group (Anseres, Colymbiformes, etc.).8The importance of accurate weight‐measurements for v

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1927.tb02180.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1927.tb02181.x

出版商:Blackwell Publishing Ltd    

年代:1927

数据来源: WILEY