THE FINCHES 147 



not so much, after all, in the details, as in the general subject, and 

 the questions arising out of it, that true interest lies. Why do birds 

 flock ? What was the origin of the habit ? Is it an initial instinct, 

 upon which, sometimes, circumstances may act as a check, or do 

 circumstances alone produce the phenomenon? The number of 

 solitary species seems a sufficient answer to the first of these ques- 

 tions ; l whilst that habits themselves, however brought about, may 

 pass, by degrees, into instincts, is a truth that can hardly be ques- 

 tioned. The rivalry and jealousy between male birds, as well as the 

 proprietary feelings and protective instinct of both parents, which 

 will not willingly suffer a too close contiguity to the neighbourhood 

 of the nest, is sufficient to keep families apart during the season of 

 domestic activities, but, when these are over, the check is relaxed, 

 and there is no jyrima facie reason why like should not seek like. If, 

 then, the numbers of the species, or the similarity of food and habits, 

 tend to produce this result, it is easy to understand how a mere state 

 of things, coming naturally about, should pass into a custom, and 

 this, in some instances, into a craving so strong as even to break 

 down the barriers just glanced at, so that nesting itself becomes 

 social. Of this there is some indication even amongst our own 

 finches, whilst their foreign relations, the Weaver-birds, 2 supply us 

 with a crowning example of it. With this trifling preface we may 

 pass from the general to the particular. 



Bramblings, so social as we have seen them in their habits of 

 roosting, are sufficiently so, even in the spring-time, for several to 

 build their nests near together, 3 sometimes, even, though this is 

 exceptional, within the confined territory of a small juniper bush. 

 When the period of domesticity is over, they yield entirely to the now 

 more dominant instinct, and gather into flocks so vast as to attain, 

 sometimes, even in Britain, a length of a quarter of a mile and a 



1 Yet the solitary habit may be induced. 



* " Hardly to be distinguished from the Fringillidce, except by their tenth primary being 

 distinctly developed," says the Cambridge Natural History. A pedantic reason then, surely, 

 for thus separating them. 



3 R. Collett, quoted in Sharpe and Dresser's Birds of Europe. 



