A Communal Winter Roost of Silver-haired Bats, 
Lasionycteris noctivagans 
(Chiroptera: Vespertilionidae) 
Mary K. Clark 
North Carolina State Museum of Natural Sciences 
P.O. Box 29555, 
Raleigh, North Carolina 27626-0555 
ABSTRACT — A communal roost of the silver-haired bat, 
Lasionycteris noctivagans, was found in January 1993 in Granville 
County, North Carolina. This is the first confirmed report of com- 
munal winter roosting for this species. 
The silver-haired bat (j Lasionycteris noctivagans ) occurs in for- 
ested areas throughout much of North America (Kunz 1982) and is 
a common migrant and winter resident across North Carolina (Lee 
et al. 1982). This bat has been found in tree cavities and behind 
loose bark and, especially while hibernating in winter, will use a 
variety of shelters including buildings, mines, and rock crevices (Kunz 
1982). It sometimes migrates in small groups (Barbour and Davis 
1969), but is generally regarded as a solitary bat. 
Most reports of large winter or summer aggregations were not 
considered reliable (Barbour and Davis 1969, Kunz 1982). Barbour 
and Davis (1969) attributed to C. H. Merriam (1884a and 1884b) 
two reports that suggested L. noctivagans occasionally forms nurs- 
ery colonies; however, Merriam did not make either observation. 
One report of 13 young bats found in a crow’s nest near Lowville 
in Lewis County, New York, was told to Merriam by Frank Hough 
some years after the discovery. Merriam (1884b:92) included this 
report under the L. noctivagans account stating that they “presum- 
ably were of the species now under consideration, because it is by 
far the most common in the region.” Additionally, Merriam (1884b:93- 
94) printed an anecdotal report of a summer aggregation described 
to him in a letter by William Brewster. While looking for wood- 
peckers on 18 June 1880 along the shores of Lake Umbagog, New 
York, Brewster found a colony of bats in a snag. He reported that 
there were “certainly hundreds and probably thousands” of bats, and 
he described them all as adults of the same “small dark-colored” 
species, “which as you [Merriam] suggest, was probably Vesperugo 
[Lasionycteris] noctivagans.” No specimens were saved, and Merriam ’s 
decision to include this report under the L. noctivagans account 
appears based on the vague physical description and Merriam’s as- 
Brimleyana 19:137-139, December 1993 
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