422 NATATORES. URIA. GUILLEMOT. 



is increased by the number of Kittiwakes (Larus tridactylus), 

 which hover around, and which breed in the small side clefts, 

 or on the projecting angles of the rock ; and by the nests of 

 two or three Crested or Green Cormorants, which, from the 

 unusual confidence they display in continuing to sit upon 

 their eggs, even when overlooked from the opposite preci- 

 pice at only a few yards distance, seem to be well aware of 

 the security of the station they have chosen. The great 

 body of the breeding birds arrives towards the end of March 

 or the beginning of April, at which time most of them have 

 acquired the perfect nuptial plumage. I have, however, ob- 

 tained them much earlier, and when the white upon the 

 throat was only giving place to the pitch -coloured black that 

 distinguishes them till after the sexual intercourse. After 

 the period of reproduction they leave the rocks, and betake 

 themselves entirely to the ocean, when the old birds undergo 

 the moult that assimilates them to the young, or Lesser Guil- 

 lemot of authors. At this time they often lose so many of 

 their quill-feathers, as to be totally incapable of flight ; but 

 these are soon reproduced, and the colonies which had made 

 the English coasts their summer quarters, retire to more 

 southern latitudes to pass the winter months. Their place 

 in this country is but sparingly supplied by a few stragglers 

 from the great bodies that, being bred in still higher lati- 

 tudes, make the friths of Scotland and its isles the limit of 

 their equatorial migration. Much difference of opinion pre- 

 vailed amongst ornithologists a few years ago, as to whether 

 this bird in the summer plumage was not specifically distinct 

 from that state of it in which, together with the young, it 

 has been called the Lesser Guillemot. But the question seems 

 now to be satisfactorily determined by the investigations that 

 have been instituted, and the increased attention latterly be- 

 stowed upon the changes, that so many birds periodically 

 undergo, and which prove their identity beyond a doubt. It 

 may not, nevertheless, be amiss to glance at the reasons ad- 

 vanced by MONTAGU, in favour of this distinction, as how- 



