430 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



flank-feathers with large subterminal sooty- brown bands or spots, 

 lower-flanks and under tail-coverts sooty-brown, latter tipped pale 

 brown or whitish, lower ones mottled whitish ; axillaries white 

 with about distal quarter brown and extreme tips white ; under 

 wing-coverts white, those round edge and bend of wing with broad 

 brown shaft -streaks or brown with white fringes, and some in 

 centre often with narrow brown shaft -streaks ; tail brown- 

 black ; primaries brown-black becoming brown on inner webs and 

 on basal portions white ; secondaries same with more or less 

 silver-grey wash and narrowly margined white and more white on 

 inner webs, inner feathers browner ; greater coverts washed silver- 

 grey and fringed white, rest of coverts as mantle. This plumage 

 is acquired by complete moult June-Sept.* 



Nestling. — (Not examined.) 



Juvenile. — Apparently as adult. 



Measurements and structure. — Wing 310-335 mm., tail 107- 

 121, tarsus 56-62, middle toe with claw 66-75, bill from feathers 

 44-49 (20 measured, but insufficient sexed material to give separate 

 measurements). Primaries : 1st minute, pointed and concealed 

 by primary-coverts, 2nd longest, 3rd 3-8 mm. shorter, 4th 15-23 

 shorter, 5th 38-45 shorter, 6th 60-70 shorter, 7th 82-95 shorter. 

 Best of structure as in Manx Shearwater. 



Soft parts. — Bill yellow-green (Audubon) in dried skins dark 

 horn-colour ; legs and feet outer side brown, inner side yellowish- 

 flesh ; iris grey -brown. 



Characters. — No subspecies. Large size, white under-parts with 

 brown patch down centre of belly distinguish it from other 

 British Shearwaters. 



Field -characters. — One of the large Shearwaters looking as big 

 as P. kuhlii, from which it is easily distinguished by the strongly 

 marked line of demarcation between brown of head and pure white 

 of throat, sides and front of neck. White of neck also runs back- 

 wards some little way so as to produce impression of a conspicuous 

 brown cap which is very diagnostic. A minor point for recognition 

 is the white tips to upper tail-coverts. With glasses sooty-brown 

 smudge on white abdomen might be made out as bird tilts over. 

 Flight as under North Atlantic Great Shearwater. Brewster says 

 will frequently glide half a mile without moving wings perceptibly. 

 (P. R. Lowe.) 



* It has frequently been stated that Great Shearwaters and Manx 

 Shearwaters moult their wing-feathers so rapidly as to become almost flight- 

 less (compare especially Prof. A. Newton, Ann. Scot. Nat. Hist., 1900, 

 pp. 142-7). In the moulting examples of Puffinus which I have examined 

 usually two adjacent primaries have been in different stages of growth, and 

 those next to them on either side full grown or old. In one case (Great Shear- 

 water, Greenland, June) the outer four primaries are all in various stages of 

 growth, giving the bird a very short-winged and flightless appearance. The 

 wing-feathers, however, are not dropped simultaneously and thus the moult 

 is not comparable with that of the Anatidse and others. — H.F.W. 



