LIFE HISTORIES OF NOETH AMERICAN PETRELS AND PELICANS. 159 



OCEANODROMA HOMOCHROA (Coues). 

 ASHY PETREL. 



HABITS. 



This is the smallest of the brown-rumped species of the genus 

 Oceanodroma, and it is not strikingly different from the other small 

 species. Its known range seems to be limited to the coast of Cali- 

 fornia, and it is known to breed only on the Farallon Islands and on 

 some of the Santa Barbara Islands. Mr. Walter E. Bryant (1888) 

 says that it is " the last to arrive on the Farallon Islands " and the 

 " rarest of the birds which breed there. They nest anywhere on the 

 island in natural cavities, particularly those under loosely piled rocks. 

 No nest is made and only a single egg is laid, although it sometimes 

 happens that an egg and downy young will be found in the same 

 place." 



Nesting. — Prof. Leverett M. Loomis (1896) writes of this species 

 on the Farallones: 



Although these petrels were breeding abundantly in all parts of the island, 

 every portion of it might have been passed over in daylight without a single 

 individual being discovered, for apparently only brooding birds occurred, con- 

 cealed in loose piles of stones, in stone walls, and under driftwood. After night- 

 fall the petrels became active. They were especially conspicuous during the 

 early morning hours of the 14th, when the auklets held their concert. As 

 I stood in the dooryard of a keeper's house every few moments one or more 

 would pass silently by, disappearing in the darkness. Their flight recalled that 

 of a Goatsucker. 



The strong musky odor of the petrels renders their discovery in the rock piles 

 easy. It is only necessary to insert the nose Into likely crevices to find them. 

 With little practice one may become very expert in this kind of hunting, readily 

 determining whether it is an auklet or a petrel that has its residence in any 

 particular cranny. Sometimes the petrels are within reach, but usually the 

 rocks have to be removed to get at them. When uncovered they generally shrink 

 away as far as they can, but occasionally one will remain on its egg. When 

 tossed into the air they fly without difficulty. Eggs with well-developed embryos 

 were the rule, but there were also fresh eggs and downy young in various stages 

 of growth. In seventeen specimens preserved the organs of reproduction, except 

 in one female, displayed marked degeneration, showing that the breeding season 

 was about over. Apparently nearly as many males as females were brooding. 

 With a single exception, all the examples taken, including a partial albino, were 

 very fat. It seemed strange to find these birds of the ocean rearing their young 

 near the dwellings and within several rods of the siren. None of the feathered 

 inhabitants of the island appeared to be alarmed at the blasts of this signal, 

 repeated every forty-five seconds when the fog settled down. 



Mr. William L. Dawson (1911) writes: 



Either this species has notably increased of late, or else earlier visitors were 

 inclined to underestimate its numbers. We found them well distributed through- 

 out the main island. Not only are all the stone walls alive with them, but they 

 occupy the minor rock-slides along with the Cassin auklet, and they even burrow 



