BLACK-FOOTED KITTIWAKE. 517 



The plumage is full, close, elastic, and blended ; but on 

 the back and wings somewhat compact. The lower surface 

 of the quills and tail-feathers Avith silky lustre. The wings 

 are very long, extending an inch and a half beyond the tail, 

 rather narrow, acute, with twenty-eight quills ; the first 

 longest, the second slightly shorter, the other ])rimaries 

 rapidly graduated ; the outer secondaries obliquely rounded, 

 the inner elongated. The tail is even, and of moderate 

 length. 



The bill is pale greenish-yellow ; the angles of the mouth 

 and the edges of the eyelids bright orpiment, inclining to 

 scarlet ; iris hazel ; feet brownish-black, with a green tinge ; 

 claws bluish-black. The head, neck, all the lower parts, a 

 portion of the back anteriorly, the upper tail-coverts, and the 

 tail, are pure white ; the back, scapulars, and upper surface 

 of the wings, including their edges, are light bluish-grey, of 

 which there is a slight tinge on the marginal lower wing- 

 coverts. The outer web of the first quill, unless just at the 

 base, and its inner web, for two inches and a half at the end, 

 are deep glossy black ; the ends of the next four quills are 

 of the same colour, diminishing in extent ; the fourth and 

 fifth with a small white space at the tip. There is a little 

 white on the tips of the other primaries, and the secondaries 

 are largely tipped with the same, the inner excepted. 



Length to end of tail IT inches ; extent of wings 36 ; 

 wing from flexure 12-^ ; tail 5 ; bill along the ridge 1^, 

 along the edge of lower mandible 2-^; tarsus 1;^ ; first toe-J^? 

 its claw -J^- 3 second toe ^-f-j, its claw -^-^ ; third toe 1-^, its 

 claw -j^ ; fourth toe l-fh>, its claw -^. 



Female. — The female is similar to the male, but some- 

 what less. 



Length 16|^ inches ; extent of wings 35 ; bill along the 

 ridge l^- ; tarsus 1^ ; middle toe and claw 2. 



The above descriptions are from individuals killed on the 

 Firth of Forth, in May 1824, compared with others. 



Variations. — In size this s])ecies varies little, the greatest 

 length being 17|^, the least 16 inches, and the extended 



