BIRDS OF GLIIKNSKY. 



193 



Common Tern, so it may be as well to point out the 

 chief distinctions : these are the short tarsus of the 

 Arctic Tern, which only measures 0*55 of an inch, 

 whilst that of the Common Tern measures 0*7 of an 

 inch ; and the dark grey next to the shaft on the 

 inner web of the primary quills of the Arctic Tern, 

 which is much narrower than in those of the Common 

 Tern. These two distinctions hold good at all ages 

 and in all states of plumage ; as to fully adult birds 

 in breeding plumage there are other distinctions, 

 the tail of the Arctic Tern being much longer in 

 proportion to the wing than in the Common Tern, 

 and the bill being nearly all red instead of tipped 

 with horn-colour. 



The Arctic Tern is not included in Professor 

 Ansted's list, and there is no specimen at present 

 in the Museum. 



165. Black Tern. Hijdrochelidon mfiya,ljmn^Uii. 

 French, '' Guifette noire," " Hirondelle de mer 

 epouvantail."*— The Black Tern is by no means a 

 common visitant to the Islands, and only makes its 

 appearance in the autumn, and then the generality 

 of those that occur are young birds of the year. 

 I have one specimen of a young bird killed at the 

 Vrangue on the 1st October, 1876. It does not 

 seem to occur at all on the spring migration; 

 at least I have never heard of or seen a Channel 

 - Temminck, ' Man. d'Ornithologie.' 



