LARIDAE. 251 



Family LARID^, OR GULLS. 



The Gulls and their allies are a large group of birds which have become 

 somewhat isolated, though they are allied to the Plovers, to the Petrels, 

 and to the Auks; but it would be difficult, if not impossible, to de- 

 termine to which of these three families they are most nearly related. 

 Forbes differed from this opinion to the extent that he removed the Petrels 

 from the vicinity of the Gulls, but placed the Ibises and Spoonbills near 

 them. Sclater elevates the Laridae to the rank of an order, placing it 

 between the Plovers and the Petrels. There are two notches on each side 

 of the posterior margin of the sternum, as in most of the Plovers and 

 Sandpipers. In the modifications of their cranial bones they belong to 

 the group which includes both the Game Birds and the Plovers. 



In their seasonal changes of plumage the Gulls and Terns differ very 

 little from the Plovers and Sandpipers. The young when first hatched are 

 covered with down and able to take care of themselves. The first feathers 

 appear almost immediately, and fully fledged young in first plumage are 

 probably riot more than a month old. It is no sooner completed than, 

 with some exceptions, they commence to moult into the plumage of birds 

 of the year, even whilst they are being fed by their parents. In February 

 they begin their first spring moult, and six months later their second 

 autumnal moult takes place in August. After this moult .the Terns are 

 in adult plumage; the small Gulls show few traces of immaturity; but 

 the larger Gulls show few signs of maturity at this age, and do not attain 

 fully adult plumage until their fourth or fifth autumn. In both moults 

 if a feather is in good condition it is not renewed, but changes colour where 

 the colours of summer and winter plumage differ. 



The birds belonging to this family have long pointed wings, short legs, 

 and small feet. The tarsus is scutellated in front and reticulated behind. 



This family contains about a hundred species, and may be regarded as 

 cosmopolitan in its range. 



The geographical distribution of the Laridae presents some features of 

 unusual interest. This group of birds may be divided into two classes, 

 one consisting of inland species, the other of oceanic species. The geora- 

 phical range of the continental species conforms in its broad lines to the 

 geographical regions as finally arranged by Sclater ; whilst that of the 

 oceanic species appears to bear no relation to them, and must be considered 



