451 



THALASSIDEOMA LEACHIL LEACH'S STORM- 

 PETREL. 



FORK-TAILED PETREL. 



Petrel de Leach. Procellaria Leachii. Temm. Man. d'Ornith. IT. 812. 

 Fork-tailed Petrel. Thalassidroma Leachii. Audubon, Ornith. Biog. IV. 



434. 

 Fork-tailed Storm-Petrcl. Thalassidroma Bullockii. Selby, lUustr. II. .537. 

 Procellaria Leachii. Leach's Petrel. Jenyns, Brit. Vert. Anim. 286. 

 Procellaria Leachi. Bonap. Comp. List, 64. 



Tail forked ; hill and feet hlack ; plumage grey ish-Uack, 

 tinged with hroion ; quills and tail hrownisk-hlack ; smaller 

 wing-coverts and inner secondaries light gretjish-hrown ; 

 feathers of the rump, sides of abdomen, and outer tail-coverts, 

 white ; upper tail-coverts white, tipped with hlack ; length 

 nearly eight inches. 



Male in Winter. — This, the largest British species, and 

 distinguished from the others by its forked tail, has the body 

 slender, the neck short, the head oblong and compressed. 

 The bill is shorter than the head, slender, much compressed, 

 decurved at the end, and acute. The upper mandible with 

 its dorsal line direct at the base, abruptly deflected at the 

 nostrils, then for a short space straight, finally arcuate and 

 much decurved, the ridge narrow at the base, narrow and 

 convex in the rest of its extent, separated by a narrow groove 

 from the sides, which are convex, the edges inclinate and 

 sharp, the unguis narrow, decurved, and pointed ; the lower 

 mandible with the intercrural space narrow and pointed, the 

 crura narrow, with the sides erect, the outer outline slightly 

 decurved, the angle slightly prominent, the dorsal line concave 

 and declinate, the edges sharp, decurved at the end ; the gape- 

 line sinuous. 



The nostrils opening directly forward from the tube at the 



