Packing of Birds 247 



more nnmerous : they were certainly scarce those two 

 seasons in that locality. Now here we have an instance 

 in direct contradiction to the suggestion that the early 

 state of vegetation is attractive to our spring visitors. 

 The crakes appeared to come earlier, in larger numbers, 

 and to be more contented and make a longer stay in the 

 colder county than in the warm one. 



The packing of birds is very interesting, and no 

 thoroughly satisfactory explanation of it, that I am aware 

 of, has ever been discovered. It is one of the most pro- 

 minent facts in their history. It is not for warmth, 

 because they pack long before it is cold. This summer I 

 saw large flocks of starlings flying to their favourite firs to 

 roost on the evening of the 19th of June. The cuckoo 

 was singing on the 17th, two days before. 



It would be interesting to know, too, whether birds 

 are really as free in the choice of their mates in spring as 

 at first sight appears. They return to the same places, 

 the same favourite hedge, and even the same tree. Now, 

 when the flocks split up into sections as the spring draws 

 near, each section or party seems to revisit the hedge 

 from which they departed last autumn. Do they, then, 

 intermarry year after year ? and is that the reason why 

 they return to the same locality? The fact of a pair 

 building by chance in a certain hedge is hardly enough 

 to account for the yearly return of birds to the spot. It 

 seems more like the return of a tribe or gens to its own 

 special locality. The members of such a gens must in 

 that case be closely related. As it is not possible to 

 identify individual birds, the difficulty of arriving at a 

 clear understanding is great. 



Why, again, do not robins pack? Why do not black- 

 birds, and thrushes, go in flocks ? They never merge 



