LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 67 



Kaeding petrels, 100 white-crested cormorants, and 500 Baird's cor- 

 morants. Professor Jones (1908) has well described it, as follows: 



Seaward Carroll Islet presents a rock precipice some 200 feet in height. A 

 stone dropped from the top, within 2 rods of our camp, would fall clear into the 

 ocean below. Landward the islet slopes at first gently, but finally at an angle of 

 nearly 70° to within 30 feet of the water, ending in another precipice there. It 

 was only along the landward side that ascent was possible, and even there one 

 must clamber up vertically for 10 or more feet, finding foothold in the weathered 

 rock. • Two sharp rock ridges jut out, one at the northeast corner, the other 

 landward easterly. The gentler slope of the top is covered with Sitka spruce 

 trees, two of them old monarchs, with a few deciduous trees, growths of elder 

 bushes, a sort of red raspberry .bush, and the ever-present salal bushes. Border- 

 ing on the steeper slopes there is a growth of grass clinging to masses of soil 

 which has lodged in the interstices between rock chips. In some places this 

 grass is seen clinging to shelves on the face of precipices. Exposed rock faces 

 are pitted and hollowed by the elements into nesting places for cormorants and 

 gulls. Other rock masses, a good deal worn down, project from the other angles 

 of the island. The waves have worn a hole completely through the island par- 

 allel to the landward side and about a hundred feet from it. Practically the 

 entire island was covered by the nests of this species, except the area covered 

 by the taller trees, and also a relatively small area on the steep slope of the 

 northeastward side. 



By covered is meant that there were nests in all sorts of situations and within 

 reasonable distance of each other, but never within striking distance of the 

 birds occupying adjoining nests. A number of nests were found beneath the 

 dense fringe of salal bushes, and many of the larger grottoes of the perpendicu- 

 lar rock faces contained a nest. Ledges, which were broad enough to afford us 

 secure footing, were also occupied by nests. Often nests could be seen on small 

 niches in the rocks. There was one nest on the murre ledge fully exposed on the 

 bare rock. Many of the more exposed nests showed unmistakable signs of 

 having been pilfered by crows. 



Professor Jones noticed that all of the gulls which were nesting 

 under the bushes were old birds with pure white heads, while many 

 of those nesting in the open showed signs of immaturity. The nests 

 were also better made than those in the open. 



We found this species nesting under somewhat different condi- 

 tions in the Aleutian and Pribilof Islands, where it was decidedly 

 the commonest large gull and universally distributed. On Bogoslof 

 Island on July 4. 1911, we found a colony of between 100 and 200 

 pairs of glaucous-winged gulls nesting on the flat sandy portions 

 of the famous old volcano. The steep, rocky pinnacles in the center 

 of the island were densely populated by countless thousands of 

 Pallas's murres. Eecent eruptions had thrown up so much volcanic 

 dust, ashes, and sand that extensive sand dunes and flat sandy plains 

 had been formed all around the island, which was entirely bare of 

 shelter and devoid of vegetation. The nests of the glaucous-winged 

 gulls were widely scattered over this area, no two being anywhere 

 near together. They were weir made of seaweed, rockweed, kelp, 



