1926] Swarth: Birds and Mammals from the Atlin Region 95 



Through the courtesy of several museums and private collectors 

 (to Avhom acknowledgment is made elsewhere in this paper) a series of 

 168 rock ptarmigan in summer plumage was brought together, repre- 

 senting many parts of the mainland of North America and some Arctic 

 islands also. A few of these localities are represented by extensive 

 series of summer birds, and some such points fortunately prove to 

 be rightly placed to illustrate certain important features of geo- 

 graphical variation in the northwest. This study has not included the 

 ptarmigans of the Aleutian Islands, Greenland, Newfoundland, and 

 Anticosti. 



In the portion of North America indicated, excluding the islands 

 mentioned, the rock ptarmigan has differentiated into three easily 

 recognizable branches. First, there is a gray -colored bird that extends 

 from Labrador westward" to the coast ranges of northern British 

 Columbia. In the east it apparently extends northward into the 

 Arctic regions ; it also occurs on islands north of Mackenzie, but else- 

 where in the west it is restricted to the southern part of the region 

 covered by the species Lagopus rupestris. Second, there is a ruddy- 

 colored form that occupies almost the entire mainland of Alaska and 

 extends eastward along the Arctic coast about to the one hundredth 

 meridian. Third, there is a dark colored form with a rather limited 

 range in the coastal region of southeastern Alaska (see fig. I). 



The first-mentioned race, the gray-colored bird, may probably be 

 assumed to represent Lagopus rupestris rupestris (Grmelin), described 

 from ' ' Hudson Bay. ' ' It was the gray coloration of British Columbian 

 birds, as compared with the ruddy Alaskan specimens, that first 

 attracted my attention, and it seems evident that this gray race extends 

 practically across the continent. There are two males and one female 

 at hand from McLellan Strait, Labrador, and one female from the 

 mouth of the Nastapoka River (east coast of Hudson Bay), Ungava. 

 The two male birds can be matched exactly in the series of Atlin 

 specimens. The female from McLellan Strait is even more gray than 

 any of the British Columbia birds ; the one from the Nastapoka River 

 is indistinguishable from Atlin skins. 



A half-grown juvenal from Ponds Inlet, Baffin Land, is a trifle 

 more gray than comparable Atlin specimens, but very slightly so. The 

 variation is no more than occurs within series from any one place. 

 The locality of capture of this specimen might be considered as within 

 the range of Lagopus r. reinhardi (see A. 0. U. Committee, 1910, 

 p. 141), but in appearance it certainly agrees with rupestris, as repre- 



