186 THE CONDOR VOL. 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 fonnd 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 pro!lounced 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 /[/. hypoleucus as 2.13 )( 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 clirnbing and patient search. I think it very probable that an occasional pair of Black-vented Shearwaters (Pu2ffnus opislhomelas) breed upon these islandg, 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 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 (]]eleraclils incanus) probably a non-breeding bird which had decided to spend the summer in the southland. Two pairs of Duck Hawks (Falco peregrinus analton) 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.
