win. 7 ORDERS OF BIRDS 519 



and probably allied to the rails rather than to the waders as is still often 

 supposed. 



Possibly related to the rails are the cariamas of South America, 

 carnivorous birds with very long legs, hardly able to fly, living largely 

 on reptiles. The Miocene *Phororhacos was a similar bird, reaching 

 6 feet high; evidently the group was successful in a region free of 

 mammalian carnivores. *Diatryma was an even larger flightless car- 

 nivorous bird, found in the Eocene of Europe and North America 

 and perhaps also related to the early ancestors of the Gruiformes, 

 though usually classified in a separate order, or near the herons. 



Order 10. Charadriiformes. Waders and Gulls 



This is a large order including the wading birds and the gulls, terns, 

 and auks, which have evolved from them. The typical waders are 

 birds that live mainly on the ground, often inhabiting open watery 

 places or marshes. They are usually gregarious out of the breeding- 

 season and are often very numerous on the sea-shore. They often 

 have long legs and long bills and feed chiefly on small invertebrates. 

 The curlews (Numenius), snipe (Capella), and sandpipers (Calidris) are 

 well-known examples. The lapwings (Vanellus) and related plovers 

 are birds found on drier land than is usual among other waders; the 

 woodcocks (Scohpax) inhabit swampy woods. 



The gulls (e.g. Larus) are a very important group of birds derived 

 from the waders and adapted to life by and on the sea. Usually they 

 have a grey or white colour, often with black head and wing-tips. The 

 young are usually darker than the adults and mottled with brown. 

 The guillemots (Uria) and little auks (Plautus) are more fully marine 

 animals, breeding in very large colonies on the cliffs. 



Order 1 1 . Columbijormes. Pigeons 



The pigeons are tree-living, grain- or fruit-eating birds, mostly 

 good flyers but retaining some primitive features. They are of world- 

 wide distribution. There is little sexual dimorphism; the nest is 

 usually simple and the eggs normally one or two and white. The young 

 are born very little developed and are nourished by the 'milk' secreted 

 by the crop (p. 508). The dodo (*Raphus = *Didus) was a pigeon that 

 adopted a terrestrial habit in the island of Mauritius and grew to a 

 large size, but was exterminated by man in the seventeenth century. 



Order 12. Cuculiformes . Cuckoos 



The cuckoos include some species that build nests but many lay 

 their eggs in those of other birds. In the common cuckoo (Cuculus), 



