6 BIRD BEHAVIOUR 



The best of all birds for observation are, of course, 

 those which live in a tame but free state in their 

 own country, such as Wood-Pigeons in London, and 

 House-Crows (Corvus splendens) in Indian towns, 

 though even here the difficulty of identifying 

 individuals is a drawback. The growing practice 

 of ringing birds, however, which is proving so 

 useful in throwing light on problems of migration, 

 will probably be of service in making records of 

 individual birds in the near future, and in this 

 connection it is worth noting that spring net-traps 

 can be obtained in which many species of birds can 

 be readily captured without injury for this purpose. 



In considering the habits of birds we have to 

 realize that they fall into two categories, which may 

 perhaps be called major and minor habits, or per- 

 haps, habits and customs. By major habits I mean 

 the leading and conspicuous life- activities of a 

 species ; its food, manner of nesting, mode of 

 association (solitary or gregarious), etc. On these 

 its life obviously depends, and to them its structure 

 is often plainly adapted. Yet, as its life depends on 

 the adjustment of its main activities to its sur- 

 roundings, it is just these habits that are particularly 

 liable to vary even in a state of nature, and especially 

 so under the influence of man's interference, direct 

 or otherwise. Habits of this sort are fairly, though 

 not completely known in the case of a vast number 

 of birds, but will always require study, as they are 

 so subject to modification by circumstances. 



The minor habits, or mannerisms as we should 



