GULL TRLBE. 
5 IQ 
the marsh-terns are specially distinguished by the rounded or slightly pointed tail- 
feathers, the short tail, which is less than half the length of the wing, the small 
beak, with the culmen less than twice the length of the metatarsus, and the feeble 
feet, in which the webs are considerably indented between the toes. All these 
terns nest in marshes, either on tussocks of grass, or among floating vegetation. 
The best known of the British species is the black tern ( H . nigra), in which the 
under-parts in the adult summer plumage are dark leaden grey; the upper tail- 
coverts and tail being grey, the beak black, the chin and sides of the face like the 
under-parts, the crown nearly black, and the under wing-coverts pale grey. On 
the other hand, the whiskered tern ( H. hybrida), which is but an occasional 
straggler to Britain from the south, has the beak blood-red, the chin and sides of 
the face pure white, the throat and breast grey, passing into blackish grey on the 
abdomen, and the 
under wing- 
coverts white. 
Abundant in 
Southern Europe, 
this tern ranges 
over a large part 
of Africa and 
^ most of Asia. 
The beautiful 
white - winge d 
black tern (H. 
leucoptera), which 
is likewise but a rare visitor to the British Isles, differs from both the preceding 
in that the upper tail-coverts and tail are white in the adult summer-plumage, the 
under-parts being black as far as the vent, and the under wing-coverts of the 
same hue, while the beak is dull red. Rare in Northern Europe, this species is 
more common in the south and east, whence its range extends over the greater 
portion of Europe. Mr. Saunders writes that “ the black tern breeds in colonies, 
the nest being situated in marshes, and formed of decayed pieces of Equisetum and 
other plants, or heaps of wrack, which rise and fall with the tide ; sometimes they 
are placed on the firmer hummocks of bog in the middle of shallow parts. The 
eggs are three in number, of various shades of ochreous clay, olive-brown, or olive- 
green, blotched with dark brown, especially at the larger end. The food of this 
tern consists chiefly of beetles and dragon-flies, with some small fish; it is also 
very partial to leeches.” 
The true terns, of which the common tern {Sterna fluviatilis) is the 
typical form, differ from the marsh-terns and their allies by the distinctly 
pointed outer tail-feathers; while they are further characterised by the shortness 
of the metatarsus, the moderately elongated tail, and the compressed and slender 
beak. With two exceptions, these terns have the crown of the head black; 
while, as a rule, the under-parts are white or grey, although in the Oriental 
black-bellied tern ( S. nielanogaster) they are black. The common species, as well 
as the Arctic ( S. macrura), roseate (S. dougalli), and Sandwich tern {S. cantiana) 
HEAD OF BROAD-BILLED TERN. 
(From Saunders, Proc. Zool. Soc., 1876.) 
