FAUNA OF THE ALEUTIAN ISLANDS AND ALASKA PENINSULA 319 



Dicrostonyx groenlandicus stevensoni 



This lemming, described by Nelson in 1929, is similar to D. g. 

 unalascensis in that it is grayer in coloration than rubricatus, 

 and does not become white in winter. It is quite common on 

 Umnak Island, but no lemmings or other native mice are found 

 farther west in the Aleutians. 



In 1937, we were informed by Mr. Stacey, owner of the domestic 

 sheep on Umnak Island, that about 1927, as nearly as he could 

 remember, lemmings became abundant. "Millions," he said, and 

 "so hard on the grass" that he feared they would "run him out of 

 the sheep business." The following year the lemmings were 

 scarce. 



The dates were a little uncertain, but apparently it was about 

 that time that a Captain Nelson, passing by Umnak Island, came 

 upon big "schools" of lemmings out at sea. 



A news account in the "Seward Gateway," dated April 18, 1932, 

 possibly refers to this same incident, and may fix the date more 

 accurately : 



Trappers on Umnak Island, in the Aleutian group, report the recent migra- 

 tion of millions of lemmings from the island. It is said the lemmings 

 traveled in immense multitudes, in a straight line to the seashore, ap- 

 parently in obedience to some blind mechanical impulse of nature. 



During the migration they moved onward in parallel columns. One trapper 

 could not induce them to deviate from the straight line. The remarkable 

 migration terminated in Bering Sea and ended in the drowning of all that 

 survived the rough journey down from the higher regions of Umnak Island. 



In his interesting book, "Fifty Years below Zero," Charles 

 Brower mentions a striking lemming migration (1943, p. 123). 

 It occurred in the latter part of May 1888, near Point Barrow. 

 The lemmings came from the southeast, at first a few bands, then 

 in "solid masses," until the "whole land was black with them." 

 "The main body, moving seaward on a 10-mile front, took 4 days 

 to pass the station. They kept on over the sea ice, finally leaping 

 into the water and swimming offshore until drowned." 



These are striking examples of lemming migrations entering 

 the sea, in the historic manner of those of Norway. It illustrates 

 an innate tendency of this rodent group as a whole, shared by 

 the lemmings of Point Barrow (which turn white in winter), 

 and their grayer and southernmost relatives of Umnak Island. 



In the spring of 1924 I observed numbers of mice of the genus 

 Lemmus in the edge of the shore ice at Hooper Bay, in the Yukon 

 Delta region. Some of these were wet. Though no actual migra- 

 tion was noted, nor any massed concentrations, the circumstances 



