416 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



bill from feathers 13.5-16 (20 measured). $ wing 147-159. Rest 

 of structure as in 0. I. leucorrhoa but tail though varying somewhat 

 almost always considerably less forked. 



Soft parts. — Bill, legs and feet black ; iris black-brown. 



Characters. — No subspecies. Forked or slightly forked tail, 

 usually considerable white on outer tail-feathers, white shafts of 

 upper tail -coverts and black tips of lower ones distinguish it from 

 other British Petrels. 



Field -characters. — Black tips to white feathers of tail-coverts 

 and squarer tail distinguish this species from 0. leucorrhoa. Generally 

 first noticed following in wake of ship ; to ordinary observer not 

 unlike a Martin. Flies low with erratic somewhat fluttering flight, 

 the legs hanging down and feet often pattering on water as its pace 

 is diminished to pick up some minute planktonic organisms on 

 which it feeds. Generally seen after storms because ocean surface 

 then strewn with dead plankton and for same reason follows ships 

 as propeller kills plankton which floats to surface some little way 

 aft. (P. R. Lowe.) 



Breeding-habits. — Breeds in burrows in ground, which are said 

 to be longer and more tortuous than those of Frigate -Petrel. Egg. — 

 One only, white, no gloss, with at times a zone of pale red spots at 

 large end. Average of 32 eggs, 33.5 X 24.8. Max. : 36 X 26 and 35 x 

 26.1. Min. : 30.8x24.1, and 31.2x23.2 mm. Breeding -season.— 

 In Cape Verde group Jan. to March : at Porto Santo apparently 

 not only in June- July, but also in Dec. -Jan. Incubation. — Period 

 not ascertained. 



Food. — No definite information. 



Distribution. — England. — Three. One picked up dead Little - 

 stone (Kent), Dec. 5, 1895 (H. Saunders, Bull. B.O.C., v, p. 37). 

 Female shot near Hythe (Kent), Nov. 8, 1906 (N. F. Ticehurst, 

 op. c, xix, p. 20 ; cf. Brit. B., n, p. 369). One picked up dead 

 Milford (Hants.), Nov. 19, 1911 (P. W. Munn, Brit. B., v, p. 252). 



Distribution. — Abroad. — Has a curiously wide distribution, 

 breeding on outlying rocks of Azores, Salvage and Madeira groups, 

 on Cape Verde Islands and probably St. Helena, as well as on 

 Hawaiian and Galapagos Islands in Pacific Ocean (birds from 

 latter two groups have been separated as distinct forms, but both 

 require confirmation.) Casual on coasts of Denmark and U.S.A. 



Genus OCEANITES Keys. & Bias. 



Oceanites Keyserling and Blasius, Wirbelt. Eur., pp. xciii, 131, 238 

 (1840 — Type according to text clearly O. wilsoni = oceanicus). 



Similar to Hydrobates and Oceanodroma, but legs much longer, 

 tarsus in front with an undivided shield, 1st phalanx of middle toe 

 as long as the distal two phalanges. 12 rectrices, tail straight or 

 emarginated. 4 species, chiefly in seas of Southern Hemisphere. 



