474 NATATORES. STERNA. TERN. 



wings, during the breeding season, whereas, in the Common 

 species, the forepart of the neck, the belly, and abdomen, are 

 nearly white, and in the breeding season frequently tinged with 

 rosy red, as in S. Boysii and Dougalln. The grey colour in the 

 present species is also of a deeper tint. When in company with 

 the others, it is easily recognised by its voice, mode of flight, 

 and other traits, which, though they might pass unheeded by 

 a common observer, are quickly seized upon by the practical 

 ornithologist. Upon the Northumbrian coast it breeds in 

 great numbers on the Fern Islands, where I corrected my 

 mistake respecting it, having at first conceived it to be the 

 Incuba- Common Tern. The colony occupies a large space on the 

 ion, &c. j g j et se i ec f- e( J 5 ant j th e 6 gg S are pl ace( i so near to each other 



as to render it difficult to traverse the site without crushing 

 some of them. They are deposited on the bare sand or gra- 

 vel, to the number of two or three each, rarely four, and 

 differ much in colour and markings. The prevailing tint 

 may be stated as a deep oil-green, with darker spots and 

 blotches. The young, upon exclusion, are covered with a 

 parti-coloured down, usually a yellowish-grey, with darker 

 variegations, but they fledge very rapidly, and within a 

 month from the time of hatching are able to fly. Until they 

 are so far advanced, they continue to be assiduously visited 

 by the parents, and are fed with the fry of the sand-launce 

 (Ammodytes Tobianus), which is taken in the manner com- 

 mon to the genus, by plunging from some height in the air. 



PLATE 90. Fig. 2. represents the Arctic Tern of the natural 



size, and in the summer plumage. 



General Bill, from the forehead to the tip, one inch and two-eighths 



tion. ni I n g5 w ith the upper mandible arched ; colour arterial 



Adult blood-red ; (in some specimens the extreme tip is black- 



J 1 " ish-red). Forehead, crown, and long occipital feathers, 



plumage. intense black. Chin, and line bordering the black cap, 



white. Neck, breast, and the whole of the upper and 



under plumage, deep pearl-grey. Outer web of the 



