LEACH'S STORM-PETREL. 453 



Variations. — The above description is taken from a 

 recent individual procured in December, 1840, besides Avhich 

 I have examined about half a dozen skins, both European 

 and American. Slight differences in tint are observed, and 

 in summer the wing-coverts in particular are lighter, while 

 the greyish-white at the ends of the longer scapulars and 

 secondaries has disappeared. The extent of white on the 

 rump varies, apparently, according to age. 



Habits. — This Storm-Petrel was discovered in 1818 by 

 Mr. Bullock in the Island of St. Kilda. Although long sup- 

 posed to be extremely rare, it has since been repeatedly met 

 with on various parts of the coast. Still it is of very uncommon 

 occurrence, compared with Th. pelagica ; but is said to be 

 plentiful on some of the coasts of North America, and on 

 the banks of Newfoundland. Mr. Audubon being the only 

 person who has given a good account of its habits, I cannot do 

 better than present an abstract of his observations. 



" The Fork-tailed Petrel, like the other species, feeds 

 chiefly on floating mollusca, small fishes, Crustacea, which 

 they pick up among the floating sea-weeds, and greasy sub- 

 stances, which they occasionally find around fishing-boats or 

 ships out at sea. When seized in the hand, it ejects an oily 

 fluid through the tubular nostrils, and sometimes disgorges a 

 quantity of food. It emits its notes night and day, and at 

 not very long intervals, although it is less noisy than Wilson's 

 Petrel. Its flight difiers from that of the other two species, 

 it being performed in broader wheelings, and with firmer 

 flappings, in which respect it resembles that of the Night 

 Hawk, Caprimulgus Virginianus, while that bird is passing 

 low over the meadows or the waters. It is more shy than the 

 other species, and when it wheels off" after having approached 

 the stern of a ship, its wanderings are much more extended 

 before it returns. I have never seen it fly close around a 

 vessel, as the others are in the habit of doing, especially at 

 the approach of night ; nor do I think that it ever alights on. 

 the rigging of ships, but spends the hours of darkness either 

 on the water, or on low rocks or islands. It also less fre- 

 quently alights on the water, or pats it with its feet, probably 



