YELLOW-BILLED CUCKOO 139 



another externally is in the arrangement of the toes, 

 two being directed backwards and two forwards. 

 This division of the toes, however, is not confined to 

 the Parrots and Cuckoos, being shared by many other 

 groups of birds, quite unlike in other particulars. 



There are a very large number of species of Cuck- 

 oos, showing a surprising range both in size and col- 

 ouration. Some are wholly black, some resplendent 

 in rich metallic emerald-green and copper, while oth- 

 ers are clad in sober hues of grey. 



Although comparatively few species are found in 

 America, among them are some of the most remark- 

 able of the Order. Africa and India are particularly 

 rich in Cuckoos. 



While the Cuckoos are somewhat solitary in habit, 

 the Anis, an exclusively American branch of this fam- 

 ily, are gregarious. A number of them combine in 

 building a nest, in which several females lay and take 

 turns in brooding the eggs. Their powers of flight 

 are not strong, but they are good walkers and runners. 



The Yellow-billed Cuckoo is common in the eastern 

 part of North America, migrating in winter to Cen- 

 tral and South America. It is greenish-grey above, 

 white below, the outer tail-feathers black tipped with 

 white, the under part of the bill yellow, the upper part 

 black. 



The Black-billed Cuckoo resembles the preceding 

 species, but in this the bill is wholly black and the tail 

 is grey, very slightly tipped with white. Its range is 

 much the same as that of the Yellow-billed Cuckoo. 



One of the best known of all this family is the Com- 

 mon European Cuckoo, a bird which is found over the 



