XXXI 

 THE CEMENT OF BIRD MASONS 



BIRDS may be divided into two classes — those 

 which build nests and those which do not. 

 To the latter belong the parasitic starlings 

 and cuckoos, which drop their eggs in the 

 nests of other birds ; those, such as plovers, which lay 

 their eggs on the bare ground ; and those which deposit 

 them in holes, in the earth, in trees, in banks, or in 

 buildings, as, for example, the Indian roller or blue 

 jay (Coracias indica). 



Interm-cdiate between the birds that build nests 

 and those which do not — for there are no sudden 

 transitions, no sharply defined lines of division in 

 nature — are those birds which merely furnish, more or 

 less cosily, the ready-made holes in which they deposit 

 their eggs. The common myna (Acridotheres tristis) 

 affords a familiar instance of this class of birds. Some 

 of the nest-builders are really excavators ; they dig out 

 their nests in a tree or bank. The woodpeckers and the 

 bee-eaters are examples of these. The rest of the nest- 

 builders actually construct their nurseries. These 

 buildings are of various degrees of complexity. Crows, 

 doves, birds of prey, herons, and a few other families 



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