1915.] 



IKTRODUCTIOIT. 



11 



of late occurrence are as follows: October 6, Teslin Lake, Yukon; 

 October 17, Dowagiac, Mich..; October 25, Johnson County, Iowa. 

 Hahn states that in southern Indiana woodchucks usually retire about 

 the middle of October and begin to clean out and enlarge their 

 burrows during the last days of February.^ 



The yellow-footed marmots go into hibernation between the 

 middle of August and the first of October, the date varying with the 

 altitude and local conditions. Individuals living in the valleys 

 retire earlier than those living higher up in the mountains. Warren 

 states that in Gunnison County, Colo., this species dens up about 

 the first of October, but individuals are sometimes seen much later.^ 

 Allan Brooks states (in epistle) that at Okanogan Landing, British 

 Columbia, practically all these marmots disappear before the middle 

 of August, but he has occasionally seen their tracks as late as early 

 October. In the mountains of Montana and Wyoming this species 

 usually enters hibernation during the last of August or the first of 

 September; Biological Survey field parties have never found the 

 animals later than the first week in September. In the Bitterroot 

 Valley, Mont., the first one seen in the spring in 1910 was on March 

 24, and by April 1 they were numerous; in 1911 one was seen there 

 by Bernard Bailey, on March 13. In western Oregon extreme dates 

 of occurrence are: February 4 (Klamath Lake), and September 25 

 (Mount Hood). 



The hibernating period of the hoary marmot begins the last of 

 September or first of October. Near Tatletuey Lake, British Colum- 

 bia, Edward A. Preble found the species stiU active a few hundred feet 

 above timber line on September 23 and 25, but none was seen after 

 the latter date. Like the yellow-footed species, the hoary marmots 

 retire earlier in the valleys than in the mountains. Heller states 

 that at Valdez Narrows, Alaska, the species went into hibernation 

 about the middle of September.^ 



Bachman thus described his observations of a pair of hibernating 

 marmots : 



In the summer of 1814, in Rensselaer County, in the State of New York, we marked 

 a burrow which was the resort of a pair of marmots. In the beginning of November 

 the ground was slightly covered with enow, and the frost had penetrated to the 

 depth of about an inch. We now had excavations made in a line along the burrow 

 or gallery of the marmots, and at about twenty-five feet from the mouth of the hole; 

 both of them were found lying close to each other in a nest of dried grass, which did not 

 appear to have been any of it eaten or bitten by them. They were each rolled up, 

 and looked somewhat like two misshapen balls of hair, and were perfectly dormant. 

 We removed them to a haystack, in which we made an excavation to save them from 

 the cold. One of them did not survive the first severe weather of the winter, ha^dng, 



1 Hahn, W. L. Mamm. of Indiana, 1909, pp. 481-482. 



2 Vv'arren, E. R. Mamm. of Colorado, 1910, p. 148. 



s Heller, Edmund. Univ. of California Pub. Zool., V, 1910, p. 339. 



