64 BRITISH BIRDS. 



result of excessive excitement to high-pitched squealing notes 

 and imitations. Thus neither the female nor the male seem to 

 have any choice ; yet again, if this is always so, and if the 

 young return to the home of their birth, how is inbreeding 

 prevented ? How does the bird which has never paired 

 choose his ground and his mate ? The method cannot be a 

 haphazard one, but to discover how this comes about will be 

 a matter of extreme difficulty, although it may be that the 

 plan of marking birds with rings will help us here. 



Mr. Howard considers that he can distinguish the " yearling" 

 Blackcap from the adult in the spring by the browner or less 

 glossy head of the cock, and he has noticed that these birds 

 are not such accomplished singers. Several of his arguments are 

 founded on the assumption that the young are always thus 

 dully coloured, but here he is on treacherous ground, owing 

 to his reliance (apparently) on work in the field only. If a 

 good series of skins of male Blackcaps be examined it will be 

 found that although some young birds have brown or brownish 

 heads in the spring following the year they were hatched, 

 others acquire a glossy black head in their first autumn. The 

 brown on the head is individual and varies in extent, and may 

 very likely be due to a want of vigour. But Mr. Howard is 

 wrong in supposing that glossy black-headed birds are 

 necessarily older than brown -headed ones. 



Another point to which we should like to draw attention is 

 the observation that the Blackcap not only carries away the 

 faeces of the young, but that it sometimes swallows them. 

 This we know is a regular habit of the Mistle-Thrush, Song- 

 Thrush and Blackbird, and it would be very interesting if 

 observations regarding it were made upon other species, 

 because as we have suggested elsewhere, it may be of 

 economical importance to the bird which is busy feeding young ; 

 the faeces may provide for the old some nourishment that the 

 young, by reason of its exceedingly rapid digestion, has not 

 assimilated. 



In conclusion, we heartily recommend Mr. Howard's book, 

 not only as containing the results of much valuable original 

 observation, but as a thoughtful piece of work. We have 

 discussed at some length a few of the points the author has 

 raised, not so much with a view to criticism as to show how 

 much there is of interest in such observations as the author of 

 this work has so perseveringly made. 



H. F. W. 



