xvm. 7 ORDERS OF BIRDS 521 



long, composed of a short humerus and long distal segments. The 

 swifts are insectivorous and have very large mouths, adapted for 

 feeding on the wing. The nests are made in holes, the eggs are white, 

 and the young helpless at birth. 



Order 17. Coraciiformes. Bee-eaters and Kingfishers 



This is a large group of birds, including the bee-eaters (Merops), 

 mainly tropical and often brightly coloured. The three anterior toes 

 are united (syndactyly). The nests are usually made in holes and the 

 eggs are white. The kingfishers (Alcedo) are modified for diving into 

 the water to catch fish. 



Order 18. Piciformes. Woodpeckers 



The woodpeckers (Picus) are highly specialized climbing, insecti- 

 vorous, and wood-boring birds. The bill is very hard and powerful 

 and the tongue long and protrusible and used for removing insects 

 from beneath bark. The tail feathers are used to support the bird as 

 it climbs the tree-trunk. The nest is made in a hole in a tree and the 

 eggs are white. 



Order 19. Passeriformes. Perching birds 



The great order of perching birds contains about half of all the 

 known species. They are birds mostly living close to the ground, 

 rather small, and of very varied habits. There are always four toes 

 arranged to allow the gripping of the perch. The display and nesting 

 behaviour is usually complicated, with a well-developed song in the 

 male. Many species build very complicated nests and the eggs are 

 often brightly coloured and elaborately marked. The young are help- 

 less at birth. Only a few of the many and varied types can be men- 

 tioned here. 



The rooks and jackdaws (Corvus) are the largest passerines and 

 perhaps 'highest' of all birds; they are mostly colonial. The starlings 

 (Sturnus) are also partly colonial and nest in holes. The finches 

 (Frifigilla, &c.) are seed-eating birds with a short, stout, conical bill. 

 The house-sparrows (Passer) are closely related to the finches and 

 have become commensals of man all over the world. The larks (Alauda) 

 make their nests on the ground. The pipits (Anthus) and wagtails 

 (Motacilla) are somewhat like the larks, largely terrestrial birds with 

 slender bills. The tree-creepers (Certhia) are tree-living, insectivorous 

 birds with long bills, showing some convergent resemblance to wood- 



