300 



VERTEBRATE ANIMALS. 



Pigeons and Doves, this sub-order includes also the remarkable 

 extinct bird the Dodo, which was of gigantic size, comparatively 

 speaking, and inhabited the island of Mauritius up to the com- 

 mencement of the seventeenth century. 



Order IV. Scansores. 



The order of Scansores or Climbing Birds is very shortly and 

 easily defined, having no other distinctive and exclusive peculiarity, 

 except the fact that the feet have four toes, of which two are turned 

 backwards and two forwards (fig. 214, B). Of the two toes which 

 are turned backwards, one is the proper hind-toe, and the other is 

 the outermost toe. This arrangement of the toes enables the Scan- 

 sorial birds to climb with gi-eat ease and readiness. Their powers 

 of flight are usually very moderate, and below the general average, 

 and their food consists of insects and fruits of various kinds. Their 

 nests are usually made in the hollows of old trees, but some 

 (Cuckoos) have the remarkable habit of depositing their eggs in the 

 nests of other birds. They are never polygamous, and the young 

 are born in a naked and helpless condition. 



214.— A, Skxill of a Parrot (Psittacits enjthacus). B, Foot of the same : a Hallux ; 

 h Index : c Middle toe ; d Outer or ring toe. (After Blanchard.) 



Upon the whole, we must regard the order of the Scansores as an 

 artificial assemblage, comprising birds which have little in common 

 save the adaptations which fit them for an essentially scansorial 

 life. Bearing this in mind, we may include in the Scansores the 

 following families : 1. The CucuUcIt, or Cuckoo family, comprising 

 the true Cuckoos and some allied birds. They are remarkable for 

 the fact that many of them are " parasitic " ; that is to say, they lay 

 their eggs in the nests of other birds. The yellow-billed Cuckoo 

 (C america.tv's), however, of the United States, builds a nest for 

 itself and brings up its own young, as do others of the family. 

 2. The Picida;, or Woodpecker family, comprising many familiar 



