LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 135 
thing goes. Fortunately it is impossible to find all the nests, or kill all the 
birds, so enough remain to stock the island again another season. 
By no means every island in this vicinity is occupied by murrelets. Within 
400 yards of the one of which I write is another of about the same size and 
topography, but strange to say, no murrelets are found on it, although there 
are two or three small colonies of auklets, the remainder of the island being 
given over to Leach’s petrels. Again, on two other small islands, also near to- 
gether, each containing about a couple of acres, and in every way alike, one is 
given over entirely to auklets, while on the other the murrelets have almost com- 
plete control. These facts cause me to believe that the birds always return 
to the island on which they have been reared. 
On June 23 our party returned to the island on which we first landed, and 
found to our great satisfaction that the murrelets’ eggs were more plentiful 
than on our former visit, and a few of them were taken. We also soon dis- 
covered that they were not especially particular in the selection of a nesting site. 
An abandoned burrow of Cassin’s auklet, a dark crevice in cliffs, under large 
broken rocks which had fallen from the latter, or under large tussocks of rank 
grass, with which the higher portion of the island was covered, would answer 
equally well. Under these almost solid bunches (the grass remaining from 
‘several previous years), the murrelets would force their way, leaving only a 
slight hole in the mass, which usually was very hard to detect. After once gain- 
ing an entrance into this matted vegetation and working their way in for 2 or 
8 feet, a shallow cavity about 5 inches in diameter and 2 or 3 inches deep, 
was scratched out and this was nicely lined with blades of dry grass of last 
year’s growth, carried in from the outside, making a very neat and snug home, 
in which the two beautiful eggs comprising a set, were deposited. Some of their 
nests were found fully 200 yards from the water. In the other situations men- 
tioned little and often no nest is made, and the eggs are deposited on the bare 
rocks, in the soft sand, or on the wet, muddy soil. I even took several sets on 
‘the bare ice at the bottom of some auklet’s burrow, the ground being still 
frozen, immediately beneath the grass and moss on July 3, when I left the 
island. 
The setting bird will sometimes leave the nest when danger threatens, but 
it will frequently allow itself to be taken from the eggs, and when brought 
to light it will screech, scratch, and bite with vigor. When released they can 
not fly unless thrown into the air, and will then often fall back to earth. One 
evening, just at dusk, I was crouched in the grass waiting for a shot at a 
Peale’s falcon (Falco peregrinus pealei), who made regular trips to the island 
to prey on the auklets and murrelets, when I heard a very low but rather 
shrill whistle. Turning my attention to the spot from which it seemed to come, 
I listened; presently I heard it again, but was still unable to locate the bird, 
which I afterwards found to be a murrelet. Subsequent observations proved 
that this was a call note uttered just about the time the setting bird expected 
the return of its mate, and was evidently uttered to attract his or her attention, 
for as far as my observations went, they, like the auklets, exchange places 
nightly, and while one attends to the home cares, the other is usually a number 
of miles out at sea on the feeding grounds. This call note is the only one I could 
attribute to this species while on land, and so ventriloquial are their powers, 
that in only two instances did I succeed in locating the nest from the sound. 
While out at sea, the ancient murrelet utters a peculiar piping whistle entirely 
different from the one uttered while on the nest. 
Two eggs are laid to a set,'the second is deposited after an interval of two 
or three days, and frequently three or four days elapse before incubation be- 
