BRITISH BIRDS 



remain concealed in their holes. Stormy weather does not prevent their coming 

 abroad, nor are they less active during calms." In the breeding season, when 

 underground, they utter, according to Hewitson {Eggs of British Birds), "a sort of 

 warbling chatter." 



As in all the Petrels, the male and female are alike in colour. 



LEACH'S FORK-TAILED PETREL. 



Oceanodroma leucorrhoa (Vieillot). 

 Plate 79. 



This species, first discovered by Bullock in 1 818 on St. Kilda, is now known to 

 breed on that island as well as in the Flannen Isles and the Outer Hebrides, also 

 on islands off the Irish coast. 



In autumn it often approaches the shores of England, and seems even more 

 liable to be driven inland by storms than the Storm-Petrel. It inhabits the 

 northern portions of the Atlantic and Pacific Oceans, breeding as far north as 

 Greenland and Alaska, and wandering south in winter. 



Like that species, it follows in the wake of vessels, when it may be distinguished 

 from the other by its forked tail, larger size, and rather lighter colour. It breeds in 

 colonies, and its single egg, which is deposited within a burrow, is pure white in 

 ground-colour, marked with a zone of tiny spots of reddish-brown. Like other 

 members of the family, Leach's Petrel is more or less nocturnal in its habits, 

 becoming active as darkness comes on, when it flits to and fro, incessantly uttering 

 its sharp querulous notes. The food is similar to that of the Storm-Petrel, consist- 

 ing of floating molluscs, crustaceans, and oily substances on the sea. 



MADEIRAN FORK-TAILED PETREL. 



Oceanodroma castro (Harcourt). 

 Plate 79. 



This species, a rare bird in the British Islands, has been thrice recorded, the 

 first at Littlestone, Kent, in December 1895, the second at Hythe, in the same 

 county, in November 1906, and the last at Milford, Hampshire, November 191 1. 



90 



