LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 193 
among the eggs looking them over and even poking them about with 
its bill until the right one was found. Sometimes a mistake is made 
and the rightful owner finds a stranger sitting on its egg, which 
leads to a little squabble. That both sexes incubate I have proven 
by finding both males and females with bare abdominal spaces. The 
incubating bird sits in a horizontal position and does not “ straddle” 
its single egg in an upright position, as has been stated; while one 
of a pair is incubating the other frequently stands beside it. 
Eggs—tThe eggs of this species show such striking and endless 
variations in color patterns that any attempt to describe them can 
not but fail to convey an adequate idea of what a large series of 
these beautiful eggs will show. The prevailing ground color is 
bluish green or greenish blue, varying from pale bluish white to 
deep “Nile blue” or from pale greenish white to “glaucous green,” 
pale “beryl green” or “malachite green”; pale shades of “apple 
green ” or “ oil green ” are rarely found; sometimes the ground color 
is pure white, varying to “cream buff” or “olive buff.” Abso- 
lutely spotless eggs of the lighter shades are occasionally found. 
Many eggs are more or less covered with small spots of various 
shades of dark brown and a few show underlying blotches of lilac 
or “ecru drab”; many are beautifully or fantastically, scrawled with 
irregular markings of “ecru drab,” “wood brown,” “raw umber,” 
“sepia,” or “clove brown.” But the prevailing types are more or 
less heavily blotched, spotted or scrawled with course markings of 
the last two shades. These blotches are often confluent in rings 
about the larger end of the egg. Some particularly handsome speci- 
mens are heavily clouded with lilac and light brown, overlaid with 
blotches of darker browns. They vary greatly in shape but are 
generally pyriform and elongated. The measurements of 41 eggs, 
in various collections average 80 by 50 millimeters; the eggs show-: 
ing the four extremes measure 87.5 by 53.5 and 67.5 by 43 milli- 
meters, 
Young.—After a period of incubation lasting about 28 days the 
young murre is hatched in a weak and helpless condition. It is 
brooded and fed by its parents until it gains sufficient strength to 
move about, but it grows rapidly and soon becomes very lively. 
While in the helpless downy stage it makes a very shrill, but faint 
peeping noise; but when about half grown and clothed in its soft, 
juvenal plumage it can stand erect and walk or run about on the 
ledges, uttering its loud, shrill, emphatic cries, which sound to me 
like the syllables “beat it, beat it, beat it.” The cliffs fairly re- 
sound with the cries of the young at this season, the last week of 
July or first week of August on Bird Rock; it is the most critical 
period in their lives, for then it is that their parents are persuading 
them or forcing them to leave the cliffs, long before they can fly, and 
