PROCREANT CRADLES' 



i°5 



a nest than the short, thick bills of the chaffinch and gold- 

 finch ; and yet the nests of these two finches are almost the 

 most perfect of those built by any British bird, while the 

 creeper's felty couch is by no means of a high order of archi- 

 tecture, though comfortable enough, no doubt, when sheltered 

 by the walls of the deep crevice in which it is usually placed. 

 Some birds, such as the petrel and guillemot, dispense with a 

 nest altogether. They simply drop their eggs in a hole in 

 the rocks, or on a ledge. In the most primitive forms of 



nest-building the breast plays as important a part as the bill. 

 A hole is pressed in soft earth or gravel by the bird's breast, 

 and rounded by the pressure of its muscle and down. Then 

 the beak may be used by the bird resting in the hollow to 

 pull tufts of grass or other litter lying within reach and to 

 pack them round its body. So the heap of material grows 

 larger and warmer as the period of incubation goes on. 

 Plovers add grass stems to the original bare hollow of their 

 nests, and by the time that the eggs are hard set they 

 usually rest on a fairly substantial mat. Gulls on their sunny 

 ledges can be seen drawing seaweed and dry mallow- leaves 

 and tufts of sea-pink up to their white breasts with yellow 



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