186 
THE CONDOR 
Von. XII 
occupying the burrows during the day are about equally divided between males 
and females. 
Murrelets are also attracted by light, as is the case with so many of the noc- 
turnal sea-birds, and I have had them enter my tent thru the front flap and under 
the sides at night when my lantern was lighted. 
The eggs of this species are laid upon the bare ground at the end of a burrow 
under a rock or in a natural cranny, and show an almost limitless capacity for vari- 
ation. Even in the same nest I have found one egg that was clear sky-blue with 
very faint markings, while the other was nearly black. In fact one rarely sees a 
set in which the eggs are perfectly uniform both as to color and size. But the vari- 
ation in size is more pronounced in the length than in the width of eggs of a set. 
The interval between the depositing of eggs was forty-eight hours in the case of 
two nests noted. With the assistance of Mr. Osburn and several others, I am able 
to give the average measurements of eighty-five eggs of B. hypoleuais as 2.13 X 
1.41 inches. They vary from 1.97 to 2.25 in length, and from 1.32 to 1.48 in 
width. Sets of one egg are as often found as those of two. Their nests are at all 
times difficult to locate and require a vast amount of climbing and patient search. 
I think it very probable that an occasional pair of Black-vented Shearwaters 
( Puffinus opisfhomelas) breed upon these islands, for there were six birds of this 
species constantly to be seen in the vicinity of the South island; and on June 2, 
just at daylight, as I was rowing to the North, I lookt up in time to see one of 
these at about a hundred yards from a steep hill-side, far above the water and fly- 
ing directly out to sea, but altho I hunted for hours, I was unable to locate the 
nest. At present, this species is not known to breed regularly farther north than 
San Martin Island, where in March, I saw 7 them congregated by the thousand, at 
about four in the morning. 
I shall omit any reference to the petrels in this article, as I have turned over 
all the information that I gathered concerning this group to Mr. Osburn, who is 
preparing a special paper on the subject. 
On July 9, I saw a single Wandering Tattler ( Heteractitis incanus ) probably a 
non-breeding bird which had decided to spend the summer in the southland. 
Two pairs of Duck Hawks ( Falco peregrin its anatum ) had their nests here, 
one pair on the North, and the other on the South island. They must do fearful 
damage among the murrelets and auklets, for I have frequently seen them catch 
and kill both species just for the fun of the thing; sometimes only knocking them 
over, and at others, carrying them for a few yards before dropping them into the 
waves. On several occasions I witnest interesting exhibitions of their truly mar- 
velous flying ability. The first and most notable time was when I was collecting 
on a very steep cliff at two hundred feet above the sea. It being a lucky day, I 
pulled a murrelet out of a cranny and releast it. As usual, it dropt like a shot 
strait down until, when it began to curve out over the water, it had attained an 
enormous velocity. When it had gotten about a hundred yards from the shore, a 
pair of Duck Hawks left a ledge below me and gave chase. The unfortunate mur- 
relet had not gone a hundred yards farther before he was. caught. I am afraid to 
venture a guess on the speed at which these hawks must have been traveling. 
When seizing a small pelagic bird, they always stop the wing-beats at the instant 
of contact and by an upward flirt of their tails, shoot strait up in the air for per- 
haps a distance of seventy-five feet. They are also responsible for the death of a 
good many petrels, as is shown by the debris below their ledges. A curious habit 
that these falcons have, is that of one snatching food from another by turning belly 
upwards and grabbing the morsel in its talons. 
