176 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no 



During the hibernating season there is considerable movement of 

 bats within the roost. Apparently the selection of a suitable spot for 

 hibernation is a hit or miss proposition. Thus the bats repeatedly 

 awaken from dormancy and move to other spots until a favorable site 

 is located. Consequently, a few flying bats are likely to be found in 

 the roost at any time, although the majority of individuals may be 

 lethargic (p. 179). To illustrate this, Pearson, et al. (1952, p. 278) 

 in midwinter marked with chalk the locations of 56 torpid bats in a 

 California cave. Temperature within the cave was 34° F. Particu- 

 lar effort was made to avoid disturbing the bats. The following day 

 there were as before 56 torpid bats in the chamber, but at least 17 

 had moved to new locations. Records indicate that males are more 

 active in winter than females. 



Local migrations: At all seasons individuals or populations of 

 P. totvnsendii may normally alternate between two or more roosts, or 

 may irregularly seek new roosts. These facts have been emphasized 

 by the banding of hibernating populations and by the observation of 

 nursery colonies. Banding operations in West Virginia (504 Plecotus, 

 Mohr, 1952, p. 7), Kansas (155 Plecotus, Twente, 1955a, p. 380), 

 and California (1500 Plecotus, Pearson, et al., 1952, p. 274) all indicate 

 movement of P. townsendii from cave to cave during even the coldest 

 weather. Much of this movement undoubtedly was precipitated by 

 the disturbance to the bats when they were banded, or when the band 

 numbers were read. Twente (1955a, p. 380) found that when thus 

 disturbed the bats invariably awakened and left the cavern, not to be 

 seen there again for several days or months, if ever. The banding 

 data indicated in addition that there was considerable movement 

 from cave to cave by bats that had not been disturbed by banding. 

 Apparently these individuals were seeking circumstances more favor- 

 able for hibernation. 



Pearson, et al. (1952, p. 276) described the effect of disturbance on 

 a nursery colony. One evening, after the adult bats had left the 

 roost, their 75 young were banded. The adults returned, picked up 

 their young, and by morning all were settled in an alternate roost 1 .3 

 miles away. How the colony quickly agreed to move and arrived 

 intact at a distant new roosting place is an intriguing mystery. 



Seasonal migrations : There is no evidence of long migrations by 

 P. townsendii. Among the 1500 banded in California by Pearson, 

 et al. (1952, p. 275) most that were recaptured were recovered at the 

 original banding site or not more than 1.5 miles from it. A young 

 male found dead 20 miles from his birthplace was the most distant 

 recovery. Twenty-four percent of 504 individuals banded in West 

 Virginia were recovered in a subsequent season, all near their banding 



