THRUSH 451 



this bright colouring attains its highest development in nestlings reared 

 in deep shade. If this be confirmed, it seems obviously connected with 

 the feeding process. 



Here it may be convenient to mention that most of the species of 

 perching birds will be treated more briefly than the members of the 

 preceding groups. 



All the British perching birds are very closely related to one 

 another, and in many cases at any rate their separation into " families " 

 must be regarded more as a matter of convenience than anything else, 

 since many of these groups do not differ, for instance, from one another 

 in anything like the same degree as do antelopes from sheep, or the 

 latter from oxen, all of 

 which are included in 

 thesingle family Bovidai. 

 Among British perching 

 birds it is noteworthy, 

 however, that the lark 

 tribe (Alaudid?e) is dis- 

 tinguishable from all the 

 rest by the circumstance 

 that the hind surface of 



the shank of the leg is covered by large transverse shield-like scales, 

 instead of being smooth with a division into two lateral halves. The 

 other families are sometimes subdivided into two sections, the larger 

 characterised by having ten and the smaller only nine primary quill- 

 feathers in the wing ; but this grouping is not followed here. Among 

 the families with ten primary wing-quills, the members of the thrush 

 tribe (Turdidai) are collectively characterised by the fact that the first 

 plumage of the nestlings is spotted or mottled ; and, secondly, by the 

 nostrils being completely open, and not concealed by hairs or bristles, 

 the latter feature distinguishing them from the fly-catchers. In this sense 

 the family includes not only thrushes and blackbirds, but likewise water- 

 ouzels, chats, redstarts, and hedge-sparrows. The range of the famih' 

 is almost cosmopolitan, and a large number of the species are migrator}-. 



Although the typical representative of both the famih' Turdidai 

 and the subfamily Turdinns is the mistlc-thrush, the characteristics of 

 the latter group may be given under the heading of the present species. 

 In all the members of the Turdinte the front surface of the shank of 

 the leg is smooth, and bristles are present at the gape of the beak. 

 While many of these birds habitually perch on trees, others spend 

 most of their time on the ground ; and their food comprises insects, 



