BIRDS 1587 



series of nest-building contrivances. The nest is built 

 before the eggs are ready to be laid, and in most cases 

 the female takes the prominent part in its construc- 

 tion. But both in the building and in the subsequent 

 brooding the male may do his share, or in some cases 

 much more. Each species usually has its own pecul- 

 iar style and material of construction, though this 

 may be adapted to varying conditions. The nests are 

 usually solitary, more rarely grouped, and very ex- 

 ceptionally (as among cassowaries and ostriches) 

 common property. Rooks, sea-fowl, herons, are fa- 

 miliar examples of breeding communities, while the 

 sociable grosbeak, the republican swallows, and a few 

 others, form even closer associations. The cuckoo 

 and the cowbird have managed by a sort of para- 

 sitism to shirk their task, and quite a number of birds 

 lay their eggs in an exceptional manner in the nests 

 of neighbors. The beak is the organ most used in 

 construction, but the pressure of the body may round 

 off the forming nest, and the feet may also be used. 

 How comfortable a nest may be made inside every 

 one knows; how adroitly hidden it may be by ex- 

 ternal decorations of moss and lichen is familiar to 

 every nest-hunter. The smaller birds usually build 

 the more beautiful nests, and every variety occurs, 

 from the comparatively careless hole in the sand 

 made by the ostrich to the skilfully suspended and 

 neatly fashioned nest of the tailor-bird. It must be 

 noticed that habits vary considerably, as the very 

 diverse nests built in different circumstances by fal- 

 con, eagle, heron, etc., well illustrate. Nests are 

 shifted to suit food-supply, and vary in structure ac- 



