ZOOGENESIS 



ship, suggesting that they would build in holes if 

 only they could find them. The English sparrow, 

 which is not a true sparrow but a weaver-bird, if it 

 cannot find a hole suitable for a nest will construct a 

 bulky nest of straw with a side entrance in a tree, thus 

 indicating its affinities. Flickers in treeless regions 

 will burrow into cliffs, and robins in sandy regions 

 make their nests without the usual cup of mud. 

 Many other similar cases could be cited. 



Some of the grebes build floating nests, like rafts, 

 that can be towed from place to place. The motmots 

 build their nests in the nests of termites, and certain 

 kingfishers of southeastern Asia make their nests in 

 holes in trees which are tenanted by bees. 



Many birds ornament their nests. Our common 

 Baltimore oriole often weaves into its pendent nest 

 bits of bright colored yarn or string, the indigo bird 

 incorporates bits of paper, the crested flycatchers use 

 the case skins of snakes, and other birds use other 

 objects, such as shells or bits of shiny stones or 

 brightly colored pebbles. One bird in India enlivens 

 the vicinity of its nest with fire-flies stuck in the 

 ground. 



But it is not only in the formation of their nests 

 that birds show mental traits which are more or less 

 parallel to those of man. The bower-birds of Aus- 

 tralia build curious runs or play-houses which they 

 ornament with bright and conspicuous objects of all 

 sorts and which have no connection with their nests. 

 Many other birds, particularly of the crow family, as 

 ravens, crows, magpies and jays, are very fond of 



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