122 SEX-LORE 



We find that in these species the male and the female 

 remain together, sharing the labour of nest-building 

 and the general care of their offspring. Some birds 

 do not build a nest, but choose natural cavities such 

 as burrows, caves, etc., to place their eggs in. The 

 cockatoo, for instance, seeks a hole in a tree, enlarges 

 it with the beak until it is big enough to allow the 

 body to enter, and then lines the interior with leaves, 

 feathers, and other materials, until a soft, warm home 

 is ready for the youngsters. The male insures safety 

 by guarding the entrance. Owls also select holes in 

 trees and line them with warm material. 



The simplest forms of nests, such as those of the 

 pigeon, crow, and heron, consist only of a platform 

 built of twigs. The magpie improves a little on this 

 by surrounding the platform with a hedge, or roofing 

 it over with twigs. A still further advance is made 

 by other birds. They first erect a platform of sticks, 

 cement it with mud, and then cover it over with a 

 dome of sticks, leaving an entrance at the side. The 

 nests of the small singing birds are still more elabo- 

 rate and skilfully made, being woven out of fine hair, 

 vegetable fibre, and wool, and softened with saliva 

 by the birds. One of the most intelligent species of 

 birds is the weaver or tailor bird, whose nest is con- 

 structed in a truly marvellous way (Fig. 44). Choosing 

 large leaves, the male and female together pierce holes 

 with their beaks along the two edges of the leaves. 

 Then the male without and the female within pass 

 straws and fibres in and out to each other through 

 the holes, stitching the leaves together until a purse- 

 like nest is completed. A row of thorns at the narrow 

 entrance keeps out all enemies. 



