NORTH AMERICAN BIRDS. 49 



27 mm.* The offensive reddish, oily fluid which this species almost 

 invariably ejects when handled or irritated probably serves as food for 

 the young. The male and female assist in the duties of incubation 

 and often both sexes may be found sitting side by side in their burrow. 

 Eggs collected on the Atlantic coast are chalky-white, finely dotted 

 on the larger end, often in a circle, with purplish-red and lilac. Twenty 

 specimens average in size 1.34x1.00. On approaching the breeding 

 ground of the petrels, not one of them is to be seen. Many of the 

 birds are far out at sea, and as night comes on those in their bur- 

 rows come forth and those out at sea return, and the air seems alive 

 with them flitting about like bats and uttering their peculiar clatter- 

 ing notes. 



108. Oceanodroma homochroa (Couss.) [725.] 



Ashy Petrel. 



Hab. Coast of California. 



This, Mr. Emerson informs me, is the rarest of the birds that 

 breed on the Farallons ; nesting anywhere in cavities under bowlders, 

 laying a single egg. 



Two eggs collected June 15, 1885, and June 8th, 1886, measure 

 respectively 30x23, 31x23.5 mm.f 



Mr. A. M. Ingersoll first found the egg of this species on South 

 Farallon in June, 1885. He described the egg as dull creamy-white, 

 with a circle of reddish spots around the large end, so fine as to be 

 almost indistinct. The large end is somewhat flattened, like the large 

 end of an acorn. It measures i.iSx .94.^ 



109, Oceanites oceanicus (KUHL.) [722.] 



Wilson's Petrel. 



Hab. Atlantic and Southern Oceans. 



Wilson's Stormy Petrel is one of the best known and commonest 

 of the smaller petrels. It is to be met with nearly everywhere over 

 the entire watery surface of the world far north in the icy regions of 

 the Arctic seas and south to the sunny isles of Southern oceans. Its 

 general habits are the same as those of Leach's Petrel. 



Dr. J. H. Kidder found it on Kerguelen Island, southeast of 

 Africa. He had previously seen them at the sea coast off the Cape of 

 Good Hope, and, on December 14, saw them out by day feeding on 

 the oily matter floating away from the carcass of a sea-elephant. The 



* 1.40x 1.06 This description of the eggs refer to the new subspecies of this Petrel, since described 

 by Mr. Bryant in a paper read before the California Academy of Sciences July 18, 1887. He has named this 

 local variety, Guadalupe Petrel, Oceanodroma leucorhoa macrodactyla. It is similar to O. leucorhoa, but 

 larger and darker. White of upper tail coverts more restricted, and the ends of coverts broadly tipped with 

 black. Pileum darker than back, lighter anteriorly. Bill broader and deeper at base than that of leucorhoa. 



1 1-18 x. 91, 1.22 x. 93. 



| Ornithologist and Oologist. Vol. XI, p. 21. 



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