LIFE HISTORIES OF NuRkTH AMERICAN DIVING BIRDS. 111 
likely to harbor this ubiquitous bird. The interstices of the stone walls contain 
them to the number of thousands. Every cavity not definitely occupied by puf- 
fin, petrel, or rabbit is tenanted by an auklet, and in many cases quarters are 
shared. If one’s imagination is not sufficiently stimulated by regular occur 
rences, it will be jogged by appearances in unexpected places—an old nest of 
rock wren or pigeon guillemot, an inner recess of a murre cave, an abandoned 
spur of puffin burrow, an overturned wheelbarrow or neglected board lying 
‘on the ground, driftwood on the beach—anything affording the slightest prospect 
of protection or cover. A pile of coal, sacked up and awaiting transfer from 
landing to siren, was found to be full of them. Since this was the rule from 
center to circumference of this magic isle, we conclude that the Cassin auklet 
is the commonest bird on the Farallones, and estimates of population anywhere 
short of one or two hundred thousand do not take account of the facts. 
Mr. A. B Howell has sent me the followinig notes on the Cassin’s 
auklet: 
There are but few of the islands along the California coast and halfway 
down the peninsula of Lower California on which this auklet does not breed. 
Coming in from the sea it selects a suitable spot, usually more than 50 feet 
above the ocean, and tunnels out a burrow in the loam, which varies from one 
to several feet in length. These are used year after year until their entrances 
are big enough to fit a puffin. When available sites of this kind become 
crowded they readily occupy niches among the rocks and the corners of caves, 
The odor emanating from the burrows strongly reminds one of a badly kept 
chicken house. Fresh eggs are found by the middle of March and may be 
found in numbers until the middle of July, though the nesting season would 
seem to vary greatly in different years. Of perhaps 50 nests examined by 
me on Los Coronados Islands the first part of July, 1910, all held eggs in 
various stages, except three which contained small young. On June 30, 1913, 
this order was reversed, and out of many nests examined by Messrs Dickey, 
van Rossem, and myself three eggs were obtained, and the remainder held 
young in all stages. It is also worthy of note that at the latter time there 
‘were not nearly as many birds breeding as at the former. The eggs are 
deposited on the bare ground or occasionally a few bits of weed. 
Mr. Chase Littlejohn sent the following notes to Major Bendire: 
This auklet arrives at the island, on which it intends to nest, between 9.30 
and 10 in the evening, according as the weather is clear or cloudy—the darker 
the sky the earlier they come—and immediately drop into the grass and are 
soon in their holes, where they both take a hand in digging and cleaning out 
whatever has accumulated since it was last occupied. After this house clean- 
ing ig done, or a new hole is dug, the nest is made, the egg deposited, and 
incubation begins at once, which is taken part in by both parents, and as near 
as I could determine these duties are exchanged nightly; while one sets the 
other is away, far at sea, on the feeding grounds. On his or her return to the 
hole a greeting note is sounded, and immediately the one on the nest answers 
and comes to within a few inches of the entrance to meet the mate which has 
just returned. Here the peculiar rasping love note is repeated over and over 
with hardly an intermission for at least half an hour (I have listened that 
long), sometimes by one and oftener by both. While this salutation is going 
on they are constantly bowing to each other, and so absorbed are they in their 
greeting that the hand can often be placed on them for a short time without 
