LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 159 
of limestone rock 30 or 40 feet high, as we walked along the stony 
beach below. Black guillemots were not common on this coast, prob- 
ably on account of the scarcity of suitable nesting sites. 
On the northeast coast of Labrador, in the summer of 1912, we 
found this species evenly distributed and one of tne commonest of 
the sea birds, as far north as Nain. Mandt’s guillemot is said to 
breed in the northern portion of the coast also, but all that we shot 
proved to be Cepphus grylle. They breed mostly on the outer 
islands, which are bare and rocky, laying their eggs in remote cavi- 
ties under the numerous piles of broken rocks or in crevices in the 
rocky cliffs which are often inaccessible. Their eggs are persistently 
collected for food all summer and it is a wonder that they are not 
entirely exterminated. We found plenty of eggs which were nearly 
fresh as late as the first week in August. We saw no young birds 
anywhere, and probably only these birds that had selected inaccessi- 
ble locations had succeeded in hatching any eggs. 
Eggs.—The black guillemot lays almost invariably two eggs, 
though occasionally one egg constitutes a full set; where more than 
two eggs are found in a nest, as some writers aave reported, these 
are probably the product of more than one female. The eggs are 
handsome and boldly marked. The ground color is dull white, often 
with a faint bluish or greenish tinge, sometimes “cream color,” or 
“cream buff.” Some eggs are fairly well covered with small spots, 
but usually the markings are grouped about the larger end, often 
forming a ring, in large irregular blotches of dark shades of brown, 
varying from “clove brown” to “sepia.” One particularly hand- 
some egg in my series is heavily blotched with “ cinnamon,” overlaid 
with “chocolate,” on a cream-colored ground, with numerous faint 
spots of “lilac gray.” Most eggs are more or less spotted and some 
sre quite heavily blotched with “lavender” or “lilac gray” of 
various shades, They vary in shape from “ovate” to “elliptical 
ovate.” The measurements of 54 eggs, in the United States National 
Museum collection, average 59.5 by-40 millimeters; the eggs show- 
ing the four extremes measure 65.5 by 42, 62.5 by 48, 55 by 42, 
and 60.5 by 38 millimeters. 
Young—Incubation lasts for about 21 days and is shared by both 
sexes. The young remain in the nest, or in the crevices among the 
rocks near it, for a long time and are fed by their parents until they 
are fully fledged or nearly so and ready to learn to fly. The prin- 
cipal food of the young seems to be rock eels, small fish, and other 
soft-bodied sea animals which their parents find among the sea- 
weed and rocks at low tide or obtain by diving. 
Plumages.—The young when first hatched are covered with thick 
down which is uniform sooty blackish above, and paler or more 
