Section IV, ISSl. [ 85 ] Trans. Eoy. Soc. Canada. 



IX. — Do any Canadian Bats migrate ? Evidence in the affirmative. 

 By Dr. C. Hart Merriam. 



(Presented by Mr. J. F. Whiteaves, May 25, 1887.) 



The belief that the bats of temperate and cold temperate regions pass the winter iu a 

 state of hibernation, is so general and widespread, that an attempt to prove the contrary, 

 even in the case of a single species, is likely to be received with surprise, if not wàth 

 incredulity. Nevertheless, I shall be disappointed if the facts here brought together fail 

 to demonstrate, that at least two species of Canadian bats regularly perform extended 

 migrations to avoid the cold of our northern winters. 



All North American bats, except when their habits have been modified by proximity 

 to man, may be classed as cave-dwelling or tree-dwelling, according to the places in which 

 they spend the day. ' As a rule, the cave-dwelling species live iu large colonies, while 

 the tree-dwelling live singly or in small companies. Now, it is well known that the 

 temperature in caves, even in high latitudes, is little affected by the external atmosphere, 

 but remains nearly uniform throughout the year ; while in holes in trees the temperature 

 is about the same as that of the surrounding air. Hence animals inhabiting caves can 

 pass the winter much farther north than species living in hollow trees. 



The Hoary Bat [Atalapha cinerea) is a tree-dwelling species, and its home is in the 

 Canadian fauna, from the Adirondack Mountains northward. Therefore, on purely theo- 

 retical grounds, it should be expected to migrate. In treating of its habits, in my work 

 entitled " The Mammals of the Adirondacks," pirblished in 1884, I said (pp. 1Y8-179) :— 

 " In the fall and early winter, isolated individuals have been procured from localities so 

 far to the southward of its usual habitat that I am constrained to believe it a migratory 

 species." "William Cooper mentions a specimen that was killed, "in the month of 

 November, near the heights of "Weehawken, in New Jersey ; " - DeKay says that he 

 " noticed two flying about quite actively shortly before noon " on December 12th, 1841 

 (locality not mentioned, but presumably Long Island, New York) ; •' Zadock Thompson 

 secured one that was taken alive at Colchester, Vermont, about October 30th, 1841 ; ^ Mr. 

 H. Wheatland, iu a communication published in the Journal of the Essex County (Mass.) 

 Natural History Society, (Vol. I, 1839, pp. ÎG-tV), states that three specimens of the Hoary 

 Bat were taken at Danvers, Mass., and all in the fall. The dates of capture are : September 

 14th, October 1st, and November 22nd, 1838. Rev. James H. Linsley, in his " Catalogue 



' Some bats take possession of deserted birds' nests and other peculiar hiding-places. During warm weather 

 the tree-dwelling bats sometimes spend the day beneath bits of loose bark, or even hanging from slender twigs. 

 ■•^ Researches on the Cheiroptera of the United States, Annals Lyceum Nat. Hist., N. Y., 1837, p. 56.. 

 ^ Zoology of New York, Part i, 1842, p. 8. ' Natural and Civil History of Vermont, 1842, p. 23. 



