170 THE STORY OF THE BIRDS 



great majority of birds appear, however, to 

 prefer the latter time. Then the punctuaHty of 

 their arrival in certain spots season after season 

 is most remarkable. Almost to the day, nay 

 almost to the hour, we may confidently look 

 for certain migratory birds to arrive, and sel- 

 dom are we disappointed. The Swifts leave my 

 Devonshire home each year almost to the day ; 

 they arrive with almost the same punctuality. 

 Some sea-birds visit their breeding-places with 

 equal punctuality. The sociability or the reverse 

 of migrant birds is also interesting. Some birds 

 migrate in a solitary way, eschewing the com- 

 pany of their kindred, so far as we can see ; 

 others always congregate for the annual journey. 

 Generally speaking, however, gregarious tenden- 

 cies are a characteristic feature of migration both 

 in spring and autumn, but more especially so 

 at the latter season. Social tendencies are also 

 common during migration, and it is no un- 

 common thing to see a large flock of travelling 

 birds composed of several species. Again, an 

 odd bird or so of one species will not unfre- 

 quently attach itself to a flock of migrants, per- 

 haps of very distantly allied birds, and journey 

 in their company. Then there are not a few 

 life-paired species in which the spring journey 



