278 THE ZOOLOGIST. 



age, time of day, weather, vehemence, size of bird, and arboreal 

 life. Accent in song, exercise of ears or of eyes in detecting 

 danger, necessity for leisure, flight in song, fluttering of wings as 

 a means of address, and singing in chorus, are all dealt with in 

 this chapter. One point claimed by the author is that a life in 

 foliage leads to a development of hearing, because by that sense 

 birds would most readily learn what was going on in their 

 vicinity ; also that a life in foliage is only suited to small birds, 

 as compared with the increased sustenance to be found in larger 

 kinds of food afforded by a more open habitat. Hence singing 

 birds are arboreal and small. The Sky Lark is not mentioned 

 here ; but possibly the author would say that the size of the bird 

 and its inconspicuous colouring enable it to survive, despite the 

 conspicuous appearance it presents when singing. 



The necessity of leisure for singers is claimed as a reason 

 why laborious birds, as the Rook and Crow, do not sing ; and the 

 effects of the demands of young birds, and of enforced idleness 

 in captivity, are here considered. 



In Chapter VII. the crux of the whole argument— the in- 

 fluence of heredity — is discussed ; and here, as elsewhere, the 

 author, though traversing a good deal of ground, has felt himself 

 obliged for want of space to cite but a few examples only in each 

 branch of the subject. He begins by proving the absolute 

 inheritance of the voice in certain non- singing birds, such as the 

 Domestic Fowl, Duck, Swan, Pheasant, &c. Other inheritors 

 of the voice are mentioned, who possess the same tones and notes 

 whether reared artificially or naturally, but we are reminded that 

 in some song-birds every note of the young is acquired by 

 imitation of the parents. 



Mr. Witchell traces a family resemblance in the cawing 

 of birds of the Crow family. He finds similarity between the 

 call-notes of several birds of the Turdidce, indicating relation- 

 ships between the Redwing and Blackbird, Common Thrush and 

 Mistle Thrush, King Ouzel, and others. The long high distress- 

 note of the Blackbird he finds to be used on similar occasions 

 by the Robin. The young of the latter approximate to the 

 Redstart, and this bird exhibits as an alarm-note a certain little 

 whistle common to several Warblers. 



Similarly the author finds the alarm-croak of the Nightingale 

 reproduced in a modified form in several of its allies. 



