SIDE UGHTS ON BIRDS 



tradition of a supposed water-builder is that of the 

 kingfisher — ^the halcyon, which was said to nest 

 on the waves of the sea — the gods vouchsafing 

 perfectly calm weather during nidification ; hence 

 the expression " halcyon days." 



Original Builders, 

 In selecting a site for a nest most birds appear to 

 follow a more or less fixed rule. Year by year the 

 rooks assemble on the summits of their ancestral 

 elms and the guillemots on the ledges of the sea 

 cliffs. With equal fidelity we find the lapwings 

 returnmg m the spring to the same rough pastures, 

 the terns to their rocky islets, the landrails to the 

 growing grass, and the woodpeckers to their holes 

 in the decayed trees. Yet instances are constantly 

 occurring which go to prove that even nest-building 

 IS m a state of evolution, and that, from time to 

 time, original thinkers arise to set aside conven- 

 tionality and to make a bold departure from the 

 traditional plan. It is interesting to note that 

 the species which exhibit the greatest tendency to 

 innovation in the direction of nest-building are 

 those most nearly associated with man. The 

 house-sparrow, starling, robin, wren, spotted fly- 

 catcher, blackbird and the two most familiar of the 

 titmice — the great and the blue— and, in a lesser 

 degiee, the pied wagtail and the redstart, are all birds 

 of the homestead, and it is to these that one looks for 

 original thinking when the annual question of the 

 selection of a nesting site arises. The house- 

 sparrow is a most daring innovator. There is 

 every reason to believe that the house-sparrow, like 

 the tree-sparrow, was originally a builder in trees 

 exclusively. Now, although still at times piling up 

 a coarse, domed structure of straw in the leafy 

 summits of beech or elm, he will boldly seize upon 



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