Passeres 



67 



blue chest-band, the House-martin (Delichon urbica) 

 with shortly forked tail, conspicuous white rump and 

 lower surface, and the Sand-martin {Riparia riparia), 

 which is not blue-black above like the others, but is 

 brown with a mottled band of the same colour on the 

 white breast. It has, moreover, a tuft of feathers above 

 the hind-toe. All three have very short beaks with 

 a wide gape. It will be seen below that the Swift is 

 not a Swallow, but a "Picarian" form aUied to the 



Swallow's nest 



Humming-birds. The nesting habits are as distinct 

 as the coloration, for both the Martins breed in colonies, 

 while the Swallow does not. It builds an open cup 

 with pellets of mud, and lines it warmly with straw 

 and feathers to hold the five or six white eggs with 

 brown and greyish markings ; the House-martin sticks 

 a half-cup of the same substance, with an aperture at 

 the top of one side, under eaves, in window corners, 

 under rock-shelves or mouldings at the top of bridges, 

 adds a bedding of straw, chaff, or softer materials, and 



5—2 



