THE NORTH ATLANTIC GREAT SHEARWATER. 433 



Measurements and structure. — $ wing 335-360 mm., tail 1 18-140, 

 tarsus 51-57, middle toe with claw 66-73, bill from feathers 50-55, 

 width at base 18.5-20 (8 measured). $ wing 325-355, bill 46-53, 

 width at base 16-19. Primaries : 1st minute, pointed and about 

 two-thirds primary- coverts, 2nd longest, 3rd 3-10 mm. shorter, 

 4th 20-28 shorter, 5th 40-50 shorter, 6th 70-80 shorter. Rest of 

 structure as in Manx Shearwater. 



Soft parts. — Bill yellow-horn ; legs and feet pale flesh, outer 

 side of tarsus, outer toe, joints and webs dusky ; iris brown. 



Characters and allied forms. — For differences of P. k. borealis 

 see under that form. P. k. edwardsii (Cape Verde Is.) is smaller than 

 typical form ; P. k. flavirostris (Kerguelen) has a longish but slender 

 bill. Large size, mottled sides of neck, yellow bill distinguish species. 



Breeding-habits. — Breeds in holes in ground and clefts of rocks, 

 sometimes in face of high cliffs, but also on low islets. Nest. — A 

 layer of dead leaves of Scilla maritima. Egg. — One only, white, 

 no gloss. Average of 65 eggs, 68.1x45.3. Max. : 73.7x44.9 and 

 65.6x52.9. Min. : 63x42 and 65x41 mm. Breeding -season. — 

 Late May or early June. Incubation. — Apparently by both sexes. 

 Period estimated as four weeks by Kriiper. Single brooded. 



Pood. — Chiefly Cephalopoda (cuttle fish), including Loligo vulgaris. 

 Also green substance, said to be leaves of Inula crithmoides and 

 once eggs of fish (Feilden). 



Distribution. — England. — One. Female picked up Pevensey 

 Beach (Sussex), Feb. 21, 1906 (ut supra). 



Distribution. — Abroad. — Mediterranean Sea, from Palestine to 

 Spain. Replaced in north Atlantic by other forms inhabiting east 

 Atlantic Islands (Azores to Canaries and Madeira), Cape Verde Is., 

 and Kerguelen group. 



343. Puffinus kuhlii borealis Cory— THE NORTH ATLANTIC 

 GREAT SHEARWATER. 



Puffinus borealis Cory, Bull. Nuttall Orn. Club, vi, p. 84 (1881 — 



"Near Chatham Island, Cape Cod, Massachusetts"). 



Puffinus kuhli fortunatus Bannerman, Bull. Brit. Orn. Club, xxxv, 



p. 120 (1915— Type, Canary Islands). 



Puffinus kuhlii borealis, J. B. Nichols, Brit. B., ix, p. 203. 



Description. — Adult male and female. Winter and summer. — Like 

 P. k. kuhlii and not to be distinguished with certainty by plumage, 

 but in most examples white on inner webs of primaries extends less 

 far towards the tip. Sept. and Oct. examples examined were in 

 full moult. 



Measurements and structure. — £ wing 350-378 mm., tail 125- 

 145, tarsus 54-60, middle toe with claw 68-77, bill from feathers 

 54-60, width at base 20-23 (16 measured). ? wing 335-368, bill 

 51-60, width at base 18-21. Thus bigger than P. k. kuhlii but 

 measurements overlapping, bill markedly thicker and deeper. 

 VOL. ii. 2 F 



