392 LARIDAA 
have found the eggs laid among broken shells, sand, and 
gravel, and sometimes surrounded with clumps of dry sea- 
weed. 
The eggs, three in number, are seldom laid before the 
last week in May, incubation not becoming general until 
early in June. ‘They vary much in colour from dark 
brownish to light stone-buff, blotched with hght and dark 
brown. 
The mottled nestlings closely harmonise with their sur- 
roundings. 
Considering their small size, Terns are wonderfully 
courageous in defence of their young and eggs. Birds of 
almost any size, predatory or otherwise, are bravely con- 
fronted, and as a rule successfully driven off. I have seen 
Kestrels, Herons, and Hooded Crows, mobbed and scolded 
to such an extent that they retreated without showing the 
least resistance. 
Geographical distribution..—The Common Tern 1s re- 
markable for its wide distribution as a breeding-species 
It is found over Temperate Europe, while westward, it 
extends to North America and eastward to Asia. It also 
breeds in North Africa. On migration it reaches Cape 
Colony, India, and other countries in Southern Asia, and 
South America as far as Brazil. 
DESCRIPTIVE CHARACTERS. 
PLUMAGE. Adult male nuptial.—Forehead, top of head, 
and back of neck, black; cheeks, chin, sides of neck, and 
throat, white; back, scapulars, and wings, dark ‘ pearl’ grey; 
the inner web of each outer primary being marked with a 
broad streak of very dark grey ; breast and abdomen, pale 
vinaceous-grey ; tail-feathers, white, edged externally with 
grey, which is darkest on the outer tail-feathers; under 
tail-coverts, white. 
Adult female nuptial.—Similar to the male plumage. 
Adult winter, male and female.—Forehead and top of 
head, streaked and spotted with white; breast and abdomen, 
white, with the merest trace of vinaceous tint. 
Immature, male and female.—Forehead, white; top of 
head and back of neck, streaked with blackish-brown; back, 
"On September 6th, 1906, I observed two Common Terns, flying 
strong and buoyantly at about a distance of 1,345 miles west of the 
British Isles, latitude 56° 14’ N., longitude 33° 2' W., North Atlantic. 
