2 BRITISH BIKDS. 



change into the plumage of birds of the year, which differs very little from the 

 winter plumage of adults ; this is effected principally by a change in the 

 colour of the feathers, only a few of which, the worn-out ones, are moulted. 

 Sometimes the change takes place after migration, but generally during 

 migration. In spring, birds of the year moult into a plumage very nearly 

 resembling the adult summer plumage; but they can generally be recog- 

 nized by the colour of their wing-coverts, which in birds of the year are 

 in summer plumage; in adults these feathers seem always to be in 

 winter plumage. The quills and tail-feathers are generally moulted twice 

 in the year, in spring and autumn ; but possibly some quills or tail-feathers 

 which are renewed in autumn are not moulted again in spring. The 

 change of plumage in autumn takes place principally by the growth of new 

 feathers, which push away and replace the old ones ; but if an old feather 

 retain its vitality it is not replaced, but changes colour the rich summer 

 tints seem to die out, and the grey winter tints to replace them. 



Birds of the year apparently moult their feathers or change colour, as 

 the case may be, more slowly than adults; and many of them do not 

 attain the nuptial plumage during their first spring. Possibly these may 

 be late-hatched birds ; they not only pass their first summer in immature 

 plumage, making no attempt to pair or breed, but they sometimes remain 

 in their winter-quarters during the whole of their first summer, or if they 

 migrate they stop short of the breeding-grounds, and while away the 

 summer in regions where adult birds are only seen passing through on mi- 

 gration in spring and autumn. (Legge, ' Stray Feathers/ 1873, p. 490 ; 

 Hume, ' Stray Feathers/ 1874, p. 288 ; Adamson, ' Some more Scraps about 

 Birds/ p. 47 ; and Swinhoe, ' Ibis/ 1863, p. 404.) 



The birds belonging to this family present a great variety of modifi- 

 cations in their external characters. The two most important are the 

 pointed wings and the un webbed or partially webbed feet with a minute 

 elevated hind toe, which is sometimes absent. The legs are never very 

 short, and the tail is never long. The toes are sometimes furnished with 

 a scolloped or lobed membrane, resembling those of the Coots and Grebes ; 

 and the middle claw is occasionally serrated, as in the Goatsuckers, 

 Herons, Bitterns, Cormorants, and Barn-Owls. The bill is so variable in 

 shape, as to be practically useless as a distinguishing character. 



This family of birds is one of the most cosmopolitan, and contains more 

 than two hundred species. About a fourth of these are found in Europe, 

 of which nearly a score breed in our islands, and about thirty more occur 

 accidentally, or more or less frequently on migration. 



