LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 121 



collected by Mr. Joseph Dixon at Demarcation Point, Alaska, on 

 August 28, 1913. Practically nothing is known about the distribu- 

 tion or life history of this decidedly boreal species. 



There are two sets of two eggs each, in Col. John E. Thayer's 

 collection, taken by Mr. Warmbath in Ellesmere Land on June 15, 

 1910. These, and I believe a few others, were sold as eggs of Kum- 

 lien's gull, which they were honestly supposed to be at that time. 

 These eggs are not strikingly different from many other gulls' eggs, 

 though they are rather more pointed than the average; the shape 

 varies from ovate to elongate ovate. The ground color is " dark 

 olive-buff," "buffy brown," or "buffy olive." The markings are 

 similar to those of other large gulls. The four eggs measure 80 

 by 51.5, 83 by 52, 73 by 49, and 75 to 52 millimeters. There is a set 

 of three eggs in the author's collection, taken by Captain Bernard 

 on Victoria Island, Arctic America, on June 27, 1914. The nest is 

 described as the " usual nest of vegetation on rocks close to the sea." 

 In these three eggs the ground color is, respectively, " deep olive 

 buff," " yellowish glaucous," and " sea foam yellow." All three are 

 quite uniformly and rather thickly covered with small spots of 

 " vinaceous drab " and various shades of dark brown, from " bister " 

 to almost black. In one egg the darkest markings are in scrawls. 

 They measure 67 by 46, 67 by 48.5, and 70.4 by 46.5. 



Very little is known about the distribution and habits of Thayer's 

 gull, but, as it is now supposed to be a subspecies of the herring gull, 

 its habits and plumage changes are probably similar to those of the 

 common species. 



Mr. Brooks (1915) says of its distribution: 



Though there is no data to determine the range of this species it must be a 

 very boreal form, and perhaps comparatively small in numbers. The Alaskan 

 specimens may have wandered from Ellesmere Land, but it seems reasonable 

 to believe that the bird may inhabit Prince Patrick, Melville, or Bathurst 

 Islands, nearly all this territory being north of 75°. 



Dr. Jonathan Dwight (1917) has studied practically all of the 

 specimens of this gull now available, some 25 in all, which he says : 

 demonstrate that the supposed new species is nothing more than a geographical 

 race of the herring gull, and should stand as Larus argentatus thayeri- 

 Thayer's herring gull. Complete intergradation between the two forms occurs 

 argentatus 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 Port Chimo, Ungava, are argentatus, and those of Cape 

 Fullerfon, north of Chesterfield Inlet, not quite typical thayeri, but farther 

 north and west all the birds are thayeri. 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. 



