400 MICHIGAN SURVEY, 1908. 



of these specimens brings out some interesting relations regarding the 

 seasonal molilts of pelage and its consequent color changes. These 

 changes, as they occur about New York City, in the Southeastern Red 

 Squirrel {S. hud^onicus loqtiax Bangs), have been studied by Allen 

 ('90). This is the common Red Squirrel of Southern Michigan. The 

 characteristic differences between the winter and summer pelages may 

 be briefly stated thus: The winter pelage (from Michigan specimens), 

 as a rule, is long and dense, with a bright rufous median dorsal band, 

 very conspicuous ear tufts, body without distinct lateral black stripe, 

 lower parts of body grayish white, sides of body yellowish olive, and 

 soles of feet furred; the summer pelage is short, lacks the conspicuous 

 rufous median band, the ear tufts, and the fur on the soles. It acquires 

 a very distinct lateral black line, the lower parts are whitish or yellow- 

 ish, and the upper parts suffused with rufous. 



The spring moult, according to Allen, begins in April or May and is 

 nearly completed during June and July. By the fall moult, a winter 

 pelage is acquired during the months of November and December. This 

 undergoes slight change, with the possible exception of an increasing 

 intensity of the broad rufous band during February and March. The 

 gradual character of these changes suggests that this process may be 

 an almost continuous one. 



A few specimens taken near Ann Arbor, Michigan, early in November, 

 show the transition from the summer to the winter pelage. In some 

 specimens the ear tufts are becoming prominent, the rufous on the tail 

 is becoming intensified and is moving forward along the mid-dorsal line. 

 One specimen (No. .32991) taken November 17, 1905, has but few long 

 hairs upon the ears but has a very broad intense rufous dorsal band, 

 a distinct black lateral line and is white below. Another (No. 33000), 

 taken December 2, 1905, has the dorsal rufous band, well developed 

 ear tufts and lacks the lateral black line. It seems probable that the 

 time of spring moulting will prove to come during April and May, as 

 in New York, but specimens are not available by which this can be 

 determined for southern Michigan. 



Turning now to the Isle Royale specimens some interesting difi'er- 

 ences become evident when the winter pelage is compared with that of 

 similar specimens of S. httdsonicus loquax from Michigan. Unfortu- 

 nately there are only two specimens in winter pelage from Isle Royale, 

 and one of these skins (No. 32138) lacks ears and feet. The other (No. 

 33066) was taken early in January, 1904; both were collected by 

 trappers. In these specimens the dorsal rufous band is only slightly 

 developed, about to that degree of general rufous suffusion seen in 

 summer specimens of S. hudsonicus loquax from southern Michigan. The 

 difference between the two forms is very striking when they are placed 

 side by side. In one specimen of hudsonicus the ear tufts are barely 

 developed, and in both specimens the lateral black stripe is indistinct; 

 the lower parts are dirty white or plumbeous; sides of the body olivace- 

 ous gray and the pelage long. In one the soles are densely furred. The 

 summer pelage of hudsonicus apparently retains the rufous median 

 stripe as in winter but is somewhat obscured by the general rufous 

 suffusion of the upper surface, the amount of rufous having been in- 

 creased on the sides; the ear tufts are, of course, lacking; the lateral 



