Incuba- 
tion, &c. 
General 
descrip- 
tion. 
Adult 
bird. 
Summer 
plumage. 
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. Boysit and Dougallii. 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 
Common Tern.—The colony occupies a large space on the 
islet selected, and the eggs are placed 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. 
PiaTeE 90. Fig. 2. represents the Arctic Tern of the natural 
size, and in the summer plumage. 
Bill, from the forehead to the tip, one inch and two-eighths 
long, with the upper mandible arched; colour arterial 
blood-red ; (in some specimens the extreme tip is black- 
ish-red). Forehead, crown, and long occipital feathers, 
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 
