BIRDS FROM THE FARALLON ISLANDS. 39 



They nest anywhere on the island in natural cavities, 

 particularly those under loosely piled rocks. No nest is 

 made and only a single egg laid, although it sometimes hap- 

 pens that an egg and doAvny young will be found in the same 

 place. The egg of this petrel was first found by Mr. A. M. 

 Ingersoll on the South Farallou, and noticed by him in 

 the " Ornithologist and Oijlogist," of February, 1886. The 

 egg is accurately described as "dull creamy white in color, 

 with a circle of reddish dottings so fine as to be almost in- 

 distinct, around the large end, which is somewhat flattened 

 like the large end of an acorn." It measured 30x24 mm. 

 (1.18x94 ins.) Two sets of petrels' eggs collected by Mr. 

 Emerson, June 15th, 1885, and June 8th, 1886, measure re- 

 spectively 30x23 and 31x23.5 millimeters. 



A young bird which was taken from the nest June 11th, 

 1886, has a heavy covering of light slaty down on the un- 

 derparts, across the interscapulars and on the head. With 

 the exception of the parts mentioned the bird is feathered. 

 The tips of wing coverts are light gray. 



11. Phalacrocorax dilophus albociliatus. 



Farallon Coemorant, — Although not the most abundant 

 of the cormorants they gather in the largest rookeries for 

 nesting. About the first of May this species begins to col- 

 lect dry kelp and stalks of the Farallon weed, which they 

 carry in large mouthfuls to their rookery, usually on some 

 rough ridge side. They are very dilatory in the work of 

 construction, resting a great deal upon the nest, whereby a 

 depression is formed on the accumulated material, for the 

 eggs. By May 10th some of the nests contain eggs, and a 

 week later every nest is covered by a sitting bird; both 

 sexes share the work of incubation, one staying on the nest 

 while the other is off fishing. 



While sitting the birds purloin material from each other's 

 nests to add to their own. 



They will lay repeatedly in the same nest if robbed. 



