LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 203 
He says further: 
When the auks deposit their eggs along with the guillemots, which they some- 
times do, they drop them in spots from which the water can escape without 
injuring them; but when they breed in deep fissures, which is more frequently 
the case, many of them lie close together, and the eggs are deposited on small 
beds of pebbles or broken stones raised a couple of inches or more, to let the 
water pass beneath them. Call this instinct if you will; I really do not much 
care, but you must permit me to admire the wonderful arrangements of that 
nature from which they have received so much ‘useful knowledge. When they 
lay their eggs in such an horizontal cavern as that which I have mentioned 
above, you find them scattered at the distance of a few inches from each other; 
and there, as well as in the fissures, they sit flat upon them like ducks, for 
example, whereas on an exposed rock, each bird stands almost upright upon 
its egg. Another thing quite as curious which I observed is, that while in 
exposed situations the auk seldom lays more than one egg, yet in places of 
greater security I have, in many instances, found two under a single bird. This 
may, perhaps, astonish you, but I really can not help it. 
E'ggs.—The razor-billed auk never attempts to raise more than 
one young bird in a season and never lays but a single egg, I believe, 
unless the first one is taken, when, of course, it will keep. on laying. 
Two eggs have frequently been found together and are probably 
in such cases incubated by a single bird, but I believe that, in such 
cases, the two eggs have been accidentally rolled together or have 
been laid by two birds. Some specimens of the eggs closely resem- 
ble certain types of eggs of the murres, but they can usually be 
easily recognized. They are less pointed, as a rule, and are never 
really pyriform. In shape they vary from “elliptical ovate” to 
“elongate ovate.” They also never show the deep blue colors of 
the murres’ eggs. The ground color varies from “ pinkish buff” to 
“ivory yellow ” or “ Marguerite yellow ” in some specimens, but more 
often it is a very pale bluish white or greenish white and often dull 
pure white. The markings are variable in size, shape, density, 
and arrangement; sometimes the egg is fairly evenly covered with 
small spots and sometimes it is boldly blotched and scrawled; 
frequently the markings are confluent in a ring around the larger 
end. The colors in the markings are only the darker shades of 
brown, from “warm sepia” or “bone brown” to black; frequently 
there are inconspicuous, underlying spots of various shades of 
lavender, lilac, or gray. The texture of the shell is coarse, thick, and 
lusterless. The measurements of 80 eggs in the United States Na- 
tional Museum average 75.9 by 47.9 millimeters; the eggs showing 
the four extremes measure 83.5 by 48, 78.5 by 51.5, 69 by 48.5, and 
75 by 42 millimeters. 
Young.—The period of incubation is about 30 days and both 
sexes incubate. Audubon (1840) says that the young have “a lisp-- 
ing note” and are “ fed freely on shrimps and small bits of fish, the 
food with which their parents supply them. They were very friendly 
