160 BULLETIN 121, UNITED STATES NATIONAL MUSEUM. 



in the level ground in front of the keepers' houses. In investigating the drift 

 area on Frauconia beach, we found almost as many petrels as auklets skulking 

 under logs and planks. In point of abundance they are easily third, possibly 

 second, on the island. 



It is evident that these petrels have a lengthy season of courtship during 

 which they spend their nights ashore, chiefly in their burrows, and return to the 

 sea daytimes. This is followed by a " honeymoon " period of some duration, 

 presumably a week or more, in which both birds remain ashore all the time. 

 As soon as the egg is laid incubation begins, and the other bird retires to sea to 

 forage. Precisely what the division of labor is from this point on as between 

 male and female remains to be determined, but it is certain that the male is 

 often found alone upon the egg. 



Mr. Chester Barlow (1894a) describes a few nesting sites, as 

 follows : 



In 1892 I found an egg on the floor of a cave about ten feet from the entrance 

 with the parent bird incubating it. The cave was dark and damp, and the egg 

 was laid on a little moss growing on the ground. It was about to hatch. This 

 year while climbing about on the summit on East End I secured a young auklet 

 (Ptychoramphns aleuticus), and after examining it let it go into a crevice in 

 the cliff. While watching it disappear I observed a forked tail of a bird vibrat- 

 ing as it breathed, and on tearing away the rocks found a petrel sitting on its 

 fresh egg. The bird was sitting with its head as far into the crevice as possible, 

 thus being protected from the light, but its tail was in view. The elevation was 

 about 200 feet above the ocean. 



I have found the petrels nesting beneath the stone walls within a few inches 

 of Cassin's auklet, but have never found any sign of a burrow made by the 

 petrel. In 1892 I took an egg from a petrel at the base of an elevated footpath 

 of the West End, and carefully replaced the stones. This year on going by 

 the place I remembered the incident and thought I would try again. On 

 stooping down I detected the familiar nmsky odor, and soon had a fresh egg. 

 It is possible that this was the same bird I found in 1892, and that it had 

 clung to this nesting site these two years. Within a foot of this petrel was a 

 pigeon guillemot {Cepplius columba) sitting on her two eggs. I found one egg 

 about two feet in a crack in a cliff plainly in view, and it proved to be fresh. 

 I suppose the bird did not discover she had selected such an open place to nest 

 in until after she had laid the egg and daylight came, when no doubt she left 

 for more secluded quarters. 



Mr. Osgood discovered a petrel of decided tastes, as regards nesting, for on 

 the brink of a cliff, beneath several loose boulders, she had constructed a nest, 

 of coarse Farallon weed, perhaps four inches in diameter. It was naturally 

 rough, but was undoubtedly constructed by the bird, as it was in such a posi- 

 tion that a larger bird could not have gained access to it. It must be luiderstood 

 that the nest and egg were entirely concealed by numerous rocks, which had to 

 be removed to permit of the photograph being taken. The egg was badly 

 incubated. 



In one in.stance I found an egg laid on an accumulation of pebbles, and 

 again quite a collection of small granite chips were used. As in the former 

 case, everything points to the bird gathering them. 



The male incubates the egg as well as the female, as two males were found 

 performing this duty. The mates of the birds incubating were never observed. 

 I believe that when an egg is taken that the petrel does not lay a second egg 

 the same season. 



