Auk 



472 Oberholser, Subspecies of Larus hyperboreus. [oct 



Larus hyperboreus barrovianus Ridgway. 



Larus barrovianus Ridgway, ' The Auk,' III, No. 3, July, 1886, p. 330 

 (Point Barrow, Alaska). 



Chars, subsp. — Similar to Larus hyperboreus hyperboreus, but smaller, 

 the bill particularly so, and relatively as well as actually more slender; 

 mantle decidedly darker; and the line of demarcation between the white 

 tips to the primaries and the pale grayish basal portions usually more 

 evident. 



Measurements. 1 — Male: wing, 444-470 (average, 458) mm.; tail, 

 178-197 (189); exposed culmen, 56-65 (61.1); height of bill at base, 20-22 

 (20.9); tarsus, 69-74 (71); middle toe with claw, 66-72 (69). 



Female: wing, 425-457 (average, 436) mm.; tail, 171-190 (180); ex- 

 posed culmen, 46-60 (52.7); height of bill at base, 17-21 (18.7); tarsus, 

 62-73 (66); middle toe with claw, 58-71 (63). 



Type locality. — Point Barrow, Alaska. 



Geographic distribution. — Western North America. Breeds on the 

 Arctic coast and islands north to Franklin Bay, northwestern Mackenzie, 

 Hershel Island, Yukon, and Point Barrow, Alaska; west to the western 

 coast of Alaska and to Unalaska Island; south to Unalaska Island, Amak 

 Island, and the coast region of northern Yukon and northwestern Mac- 

 kenzie; east to Amak Island, and the coast region of western Alaska and 

 Franklin Bay in northwestern Mackenzie. Winters north to the Pribilof 

 Islands and the Aleutian Islands; and south along the Pacific Coast to 

 Monterey, California. Accidental in northern Texas. 



Remarks. — Mr. Robert Ridgway first noticed the differences 

 characterizing this race, and many years ago described it from a 

 specimen taken at Point Barrow, Alaska, as a distinct species, 

 under the name Larus barrovianus. 2 His emphasis on the rela- 

 tively greater depth of the bill at the angle of the gonys, as com- 

 pared with its depth at base, which now proves to be an inconstant 

 character, was the evident reason for the rejection of the form by 

 Dr. Dwight, 3 and its relegation as a synonym to Larus hyper- 

 boreus. Although the relatively greater depth of the bill at the 

 angle of the gonys proves to be valueless as a character to separate 

 Larus barrovianus, this bird is very readily recognizable by its 

 usually smaller size and particularly smaller bill, but especially 



i From Dwight, ' The Auk,' XXIII, No. 1, January, 1906, p. 28, except for dimensions 

 of bill, which have been remeasured for the present use. 

 2 ' The Auk,' III, No. 3, July, 18S6, p. 330. 

 3 ' The Auk,' XXIII, No. 1, January, 1906, pp. 27-29. 



