414 Dwiacut, Status of Thayer’s Gull. las 
geographical race of the Herring Gull and should stand as Larus 
argentatus thayeri — Thayer’s Herring Gull. 
Complete intergradation between the two forms occurs, argenta- 
tus prevailing south of Hudson Strait and of the northern shores 
of Hudson Bay, while northward probably throughout the Arctic 
archipelago of Canada, thayeri seems to be the common form. 
Breeding birds of Ft. Chimo, Ungava, are argentatus, and those 
of Cape Fullerton, north of Chesterfield Inlet not quite typical 
thayert but farther north and west all the birds are thayert. The 
localities from which I have seen breeding specimens are Buchanan 
Bay, Ellesmere Land, Browne Island (south of Cornwallis Island), 
Kater Point, Coronation Gulf, Bernard Harbor, Dolphin and 
Union Strait and Cape Kellett, Banks Island. 
Thayer’s Herring Gull probably winters chiefly on the Pacific 
Coast for I have examined a number of specimens from Barkley 
Sound, Departure Bay and Comox, Vancouver Island, British 
Columbia. I also have an adult female in my own collection taken 
on the north shore of the St. Lawrence at Tadousac, Quebec, July 
26, but this specimen is doubtless a wanderer from the north for 
dissection showed it to be a bird past the breeding stage. 
The plate (Plate XV) shows so well the chief character by which 
the two races may be distinguished that little need be said except 
that thayerz is a little smaller and is apt to have the primaries of a 
slatier black. Fig. 2 represents the wing pattern of the type of 
thayert (M. C. Z. No. 40336, & June 10, Ellesmere Land). Other 
specimens show a great diminution of white on the first and second 
primaries and a subterminal band of black on the first, while speci- 
mens of argentatus often have the first primary with a completely 
white tip. 
The describer is further to be congratulated for discovering a gull 
with characters that create a strong suspicion as to the affinities 
of Larus kumlient. If thayert were crossed with Larus leucopterus 
we would expect just such a series of hybrid specimens as now are 
placed under the name kwmlieni, but this is a matter for future 
consideration. 
