NIDIFICA TIOiV. 269 



more frequently than anywhere else, on the ground. Again 

 these nests are variously formed and joined together. They 

 are flat and loosely built of coarse materials, in the case 

 of most birds of prey and Herons, and these birds are called 

 platform-builders; or, they are more or less cup-shaped, 

 rimmed up, as in the case of the majority of nests built 

 about trees and bushes, and on the ground; or, they are 

 more or less basket-shaped, as, for example, the nests of the 

 Red-winged Blackbird and the Vireos; or, they are sewed 

 together, as those of the Orioles, or that of the famous 

 Tailor-bird; or, they have the structure of a loose felt; or, 

 they are dome-shaped. Hence, some very intelligent writers 

 have attempted to classify birds according to their styles of 

 nidification, calling them carpenters, masons, miners, plat- 

 form-builders, basket-makers, felt-makers, weavers, cement- 

 ers, tailors, etc. But this method of classification fails to 

 conform to any other system, and bears no relation what- 

 ever to the most important data for determining orders. 

 Birds so similar in structure and habit, as to represent the 

 same order, may vary essentially in their nidification. Most 

 kinds of Hawks, for instance, build platform-nests in trees, 

 while other kinds construct quite different nests on the 

 ground, and others still lay their eggs in cavities of trees, 

 almost without any nest whatever. The different kinds of 

 Swallows also adopt widely different modes of nesting, some 

 occupying cavities in trees or stumps, while others are 

 miners, tunneling a cavity into the ground, and others still 

 are cementers. Besides, the above method is imperfect in 

 itself, failing to make provision for some very important 

 groups, as those which commonly occupy cavities already 

 prepared, or those which lay their eggs on the ground with- 

 out any nest, or those which build their nests, raft-like, on 

 the water. Nor does the same species always construct or 



