Least and Leach's Petrels 119 



that name and on the coast of South America. It is slightly larger and has the 

 upper tail-coverts entirely white and the tail slightly emarginate instead of even 

 or rounded. 



Least Petrel. Very closely related is the Least Petrel (Halocy plena micro- 

 soma], found along the Pacific coast from Lower California to Panama, the sole 

 representative of its genus. It is only about five and three quarters inches long, 

 and differs from the last mainly in possessing a rounded tail and in the absence 

 of the white rump. It is a rare bird, and but little is known of its habits beyond 

 the fact that it nests on San Benito, a small rocky island some fifty miles off the 

 coast of the peninsula, placing its pearly white egg on the bare rock, in the crev- 

 ices of rocky ledges, or among the loose stones. 



Leach's Petrel. Also closely allied are the numerous species of Oceanodroma, 

 which differ mainly by their larger size, distinctly forked tails, and the tarsus 

 shorter rather than longer than the middle toe and claw. Their range is chiefly 

 in the seas of the Northern Hemisphere, coming southward more or less regularly 

 to the coast of Peru and the island of St. Helena. Of the dozen or more forms, 

 Leach's Petrel (O. leucorhoa) is one of the best known. It is uniform sooty, 

 rather darker above, and belongs to that section of the genus characterized by a 

 white rump patch ; its length is eight inches. It is equally at home in the North 

 Atlantic and North Pacific, its habits being very similar to those of the Stormy 

 Petrel; in fact, it is the common " Mother Carey's Chicken" of the New England 

 coast. It breeds abundantly on the Atlantic coast of North America from Casco 

 Bay, Maine, to Greenland, at various points on the European coast, as well as 

 the coast of Alaska in the Pacific. The nest is in a burrow, often several feet 

 deep, made usually in peaty soil. 



Wilson's Petrel. A little larger than the Stormy Petrel, and often confused 

 with it under the name of "Mother Carey's Chicken," is the Wilson's Petrel 

 (Oceanites oceanicus], of the Atlantic and Indian oceans, typical of the subfamily 

 Oceanitina, in which the leg bones are longer than the bones of the wing, the 

 claws are very flat and broad, while the wing has ten, instead of at least thirteen, 

 secondaries, as in the last subfamily. About seven inches in length, Wilson's 

 Petrel is sooty black above, somewhat lighter below, while the longer upper tail- 

 coverts are white and the wing-coverts grayish, margined with whitish. It 

 breeds on various islands in the South Atlantic in the months of January and 

 February, after which it is widely dispersed, becoming abundant, for example, in 

 August, off the coast of North America from New Jersey to Newfoundland. Its 

 nest is found in chinks and crevices among rocks, and the single egg is usually 

 sprinkled and dotted with pink around one end. A second species known as 

 the Graceful Petrel (O. gracilis] is found off the Pacific coast of South America, 

 from Chile to the Galapagos Islands, and differs in having the tail distinctly 

 forked, the abdomen white, and the webs of the feet dusky instead of yellowish. 



Sea-nymph. Closely allied is the pretty little Petrel known as the Sea- 

 nymph (Garrodia nereis], which is found in the Southern Ocean from Kerguelen 

 Island to New Zealand and the Falkland Islands, and is the only member of 

 its genus. It is a little more than six and one half inches long, and has the head, 



