Nests and Eggs 163 



other birds and leaves them to hatch it out and bring up 

 the young Cuckoo, there are other members of the Sub- 

 Order Cuculi which build their own nests, rear their own 

 young, and make most affectionate parents. 



Humming-birds lay white eggs, but their cup-shaped 

 nest, though built in an exposed place, is generally made 

 so as to assimilate with its surroundings, as is often done 

 by our Common Flycatcher (Musdcapa grisola), and other 

 birds. The remarkable mud-like nest of the Guacharo 

 (Steatornis) is alluded to below (p. 189) ; it is one of the 

 most wonderful of all nests, and is not unlike that of the 

 Flamingo in appearance. Some Swifts, as has been seen, 

 make most extraordinary nests, such as could hardly be 

 supposed to be the work of members of the same Sub- 

 Order of Birds, for the majority of them have no artistic 

 tastes at all, and construct the roughest of nests of materials 

 which they procure on the wing, agglutinated together by 

 the saliva of the birds themselves. On the other hand, a 

 wonderful hanging nest is sometimes made and attached 

 to a rock, while the Tree-Swifts {Macrodipteryx) are ap- 

 parently responsible for the smallest nest constructed by 

 any bird in proportion to its size. 



Owls always lay white eggs, and mostly nest in the hole 

 of a tree, but not invariably, as one day-flying species at 

 least, viz. the Snowy-owl (Nyctea nycted), makes its nest in 

 the open. Among the Birds of Prey the greatest difference 

 exists in the colour of the eggs, which range from nearly 

 white to the most richly-marked and beautiful eggs of any 

 known birds. Throughout the Herons, Ducks, and Geese, 

 an evident type of egg prevails, that of the former being 

 plain blue or white, and that of the latter being buff, olive, 

 or whitish, without any spots, but in the Flamingoes, as 

 well as in the Pelicans, Cormorants, and Gannets, the egg 

 has a peculiar chalky covering, which has to be removed 

 before the real colour of the egg can be seen. This is a 



