CLOTHING OF ANIMALS. 17 



becomes again mottled, and the bird loses much of its 

 beauty. Even the young bird:^ in their autumnal dress re- 

 semble their parents in the mottled plumage, which like- 

 wise becomes white at the approach of winter. 



Among the aquatic birds, similar changes in the colour 

 of the plumage have been observed. The black guillemot 

 (Uria grylle), so common on our coasts, is of a sooty black 

 colour during the summer, with a white patch on the wings. 

 During winter, however, the black colour disappears, and 

 its plumage is then clouded with ash-coloured spots on a 

 white ground. In the winter dress it has been described 

 by some as a distinct species, under the name of the spotted 

 guillemot. In the more northern regions, as in Greenland, 

 for example, this bird, in winter, becomes of a pure white 

 colour. 



These changes of colour, which we have already men- 

 tioned, extend throughout the whole plumage of the bird ; 

 but, in some instances, the change takes place on a small 

 pai't only of the plumage. Thus the little auk {Aka alle), 

 during summer, has its cheeks and throat of a black colour, 

 but in winter these parts become of a dirty white. In this 

 its winter garb, it is often shot on our coasts. Its sum- 

 mer dress induced Pennant to consider it as a variety, 

 and as such to give a figure of it in his British Zoology. 

 The black-headed gull {Larus rid'ibunchis) has a black 

 head during summer, as its English name intimates. Du- 

 ring the winter, however, the black colour on the head 

 disappears; and, when in this dress, it has been regarded 

 by many as a distinct species, under the name of the Red- 

 legged Gidl. 



In many other birds there is a remarkable difference, in 

 point of colour, between the summer and the winter plu- 

 mage, although not so striking as in those which we have 

 already noticed. The colours of the summer feathers are 



VOL. II. B 



