DR. THEODOR NEUMANN. 161 



bird ; he turns round and round, while holding his 

 tail up nearly perpendicularly and pressing the ma- 

 terials. The upper part of the nest-wall receives its shape 

 through the alternate work of the breast, the shoulders 

 and the neck ; the rini of the nest is shaped with the 

 lower part of the beak or the chin, especially through wag- 

 ging movements of the tail ; it is haally smoothed by a 

 stroking movement of the beak. Long stalks, which are 

 to be wrapped around twigs, are always first broken or 

 bent and made pliable ; lumps of clay, used by some 

 birds, are kneaded for some time before use. Any bird 

 that builds with cure takes away all stalks which protrude 

 outside or inside, and if he finds that the nest itself is in- 

 sufficient, does not hesitate to enlarge it or heighten its 

 rim, often even after eggs are lying in it. 



Some birds build common nests, and the different 

 mothers lay their eggs together and may even sit on 

 them in turns; others erect a main building, a tenement 

 house, and divide that into different compartments, each 

 of which serves as a domicile for one family ; still others 

 try to find a residence in the nests of other birds, es- 

 pecially in the substructure, and hatch their young to- 

 gether with their hosts. 



In striking contrast to some of these birds, which pro- 

 duce really wonderful works of art, stand others which 

 practically do not build any nest at all, and with these 

 our review should be begun, although naturally not 

 much can be said about them. Such birds as make no 

 nests whatever, but deposit their eggs on the bare ground, 

 or in some sheltered hollow, are the condor (Sarcorham- 

 phus gryphus), some parrots, and a few others. Some 

 scrape at least the earth away until a small hole is made 

 which, however, does not yet show the slightest lining, 

 either with grass, leaves or feathers. To these belong the 

 ostrich (Struthio camelus), the bustard (Otis tarda), the 

 peewit (Xema ridibundus). 



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