210 laridjK. 
This bird is very much like the Sandwich Tern {S. cantiaca) , 
but is a trifle larger and has the bill yellow. I found, on com- 
paring male specimens shot on the same day, that it differs 
from that species also in having the bill stouter in proportion, 
and the lower mandible slightly angulated, or " Gull-billed." 
The feathers of the black crest are more elongated ; and the 
upper tail-coverts and tail are grey, the same colour as the 
back. The primaries underneath are more broadly marked 
with grey next the shafts ; and the tarsus is rather longer. 
301. Sterna hirundo, Linn. The Arctic Tern. 
I obtained this Tern in one instance in winter plumage in 
the Straits of Gibraltar ; and there is no doubt that it occurs 
regularly on its migration south; but it is very difficult 
to get specimens of the Terns in winter for identification. 
The A-rctic Tern is distinguished from the common Tern [S. 
^Mviatilis) by its much shorter tarsus ; and the adults have 
the tail longer than in that species. 
Total length about 15 inches, tarsus 0*55. 
302. Sterna fluviatilis, Naum. The Common Tern. 
Favier includes this species in his notes, and states that it 
is found near Tangier in large flights on the coast during mi- 
gration, passing south during September and October. Pos- 
sibly he may mean the previous species. 
The common Tern is frequently seen in autumn and spring 
in the Straits, and, I think, will very possibly be found nesting 
near Cadiz. 
This species has the tarsus lonff, measuring from 0*7 to 0"75 
inch ; the wings reach beyond the tail. 
Total length about 13 inches. 
303. Sterna minuta, Linn. The Little Tern. 
" This small Tern is seen near Tangier, passing in small 
flights along the coast and on the rivers and lakes. They arrive 
during May, and return in September, some, however, remain- 
ing in the country to breed. They all retire south for the 
winter.^^ — Favier. 
The Little Tern is onlv a summer visitant around Gibraltar, 
