512 COLYMBIDAi 
Voice.—The harsh, discordant bark is generally heard 
when the bird is on the wing. It resembles the syllables 
kark-kark, shortening sometimes into kak-kak-kak. 
Food.—F ish are consumed in large quantities, the bird 
often gorging itself with sprats, flat-fish, eels, &c. Hresh- 
water fish are taken, but those of the sea are preferred, 
and even when nesting on inland lakes at some distance 
from the coast, the young are fed upon sea-fish conveyed by 
their parents at frequent intervals during the day. 
Nest.—Vhe nesting-sites are rather similar to those of 
the Black-throated Diver, but are frequently situated in 
wilder localities. A favourite resort 1s the margin of a 
mountain-tarn, sometimes elevated many hundred feet above 
the sea-level. Thus in Ireland a nesting-site described by 
Mr. Ussher was beside a small mountain-lake, the most 
elevated of a series, and more than three miles from the 
nearest bay. The nest was scraped in the peaty surface of 
a bank, on the verge of the open water, on swampy ground 
amid flowering bog-bean. The birds flew to the sea to fish, 
returning at night. When the female was hatching the male 
was generally on the lake. The nest is always very close 
to the margin of the lake. ‘‘'The sitting bird hes flat down 
on the eggs, and, when disturbed, glides into the water, and 
at first swims very low; then, bending the head and neck 
forwards, it disappears with a gentle plunge which hardly 
leaves a ripple; but I have noticed that if my stay near the 
nest was prolonged, the bird would swim high, snapping 
the mandibles and turning the head with a jerking action, 
while occasionally stopping to drink” (Saunders, Man. 
Brit. Birds, 2nd Eidit., p. 716). 
The eggs, two in number, are greenish-brown, spotted 
with umber. They are laid at the end of May or during 
the first week in June. 
In Great Britain this species nests from Argyll north- 
ward to the Shetlands and Orkneys, and westward to the 
Hebridean Islands. The breeding-haunt in co. Donegal 
appears to be the only one in Ireland. 
Geographical distribution.—Abroad, it breeds in Arctic 
and Sub-arctic Europe, Asia, and America, having a cir- 
cumpolar distribution. In autumn and winter it migrates 
southward over Kurope (visiting the Mediterranean, Black, 
and Caspian Seas), Asia to China and Japan, and along both 
sides of the American sea-board to about lat. 25° N. 
