152 BULLETIN 121, UNITED STATES NATIONAL MUSEUM. 



tions. Its close resemblance to other forked-tailed species may have 

 caused it to be overlooked, and we really do not know very much 

 about its distribution. 

 Nestmg. — Mr. A. W. Anthony (1898Z>) says of its nesting habits : 



On Guadalupe island a colony of 0. macrodactyla were found breeding among 

 the pines and oaks at about 2,500 feet above the sea. Well incubated eggs were 

 taken March 24, and well grown young the middle of May. The range of 

 variation In breeding in these three species of Oceanodroma presents an inter- 

 esting study. The Guadalupe petrel, with a breeding season e^irly in March, 

 leaves the colony altogether by June 10, by which time 0. socorroensis has not 

 begun to lay, and O. melania ' is still later. I have found' the last species 

 incubating as late as September 8. I am quite sure that only one young is 

 raised each year, though each species seems to have a rather long nesting 

 season. , 



Little attempt is made at nest building by either the Socorro or black petrel, 

 though a few sticks are often dragged into the burrow with an evident desire 

 to construct soibething resembling a nest. The Guadalupe petrel, however, 

 nearly always has a few dry oak leaves or pine needles at the end of the 

 burrows I have opened, it making a much better attempt at nest building, 

 owing perhaps to the fact that the burrows are dug among the trees where 

 this class of nesting material is abundant, whereas the other species nest on 

 barren islands and can not so readily obtain desirable material. 



Mr. Henry B. Kaeding (1905) adds the following: 



This species, peculiar to the immediate vicinity of Guadalupe Island, breeds 

 sparingly on the island, eggs taken on the 25th of March being slightly Incu- 

 bated; the birds may be seen at sea near the island. The, breeding habits of 

 this petrel differ materially from the other petrels found breeding In these 

 waters in that they lay their eggs at least 100 days earlier than the others, 

 and also instead of selecting low, sandy' or rocky situations for their burrows, 

 are only to be found nesting in burrows at the extreme top of Guadalupe 

 Island, at art altitude of over 4,000 feet above sea level, and in pine and 

 cypress groves at that. 



Mr. W. W. Brown's notes, published by Messrs. Thayer and 

 Bangs (19b8) give a different impression, as to the breeding dates; 

 he took a series of a dozen adults and three downy young, between 

 May 28 and June 17, also a single egg on the latter date; his notes 

 state: 



This species was abundant at night about its nesting burrows on, the pine 

 ridge at the northern end of the island. Most of the burrows that we opened 

 were empty, the breeding season being about over; three, however, contained 

 one young each, and one, one egg. ' ' 



The burrows were of various lengths and usually led between or under 

 heavy fragments of rock, making it very difficult, in many cases impossible, to 

 reach the end. We found no'adult birds in the burrows. After the young are 

 hatched the old birds appear to come in only at night to feed them. The one 

 egg we secured was in a deserted burrow fifteen inches long, and lay in a 

 somewhat enlarged depression at the end. It was white with a faint wreath 

 of reddish brown specks at the larger end. 



