SREL Reprint #2042

Spatial ecology and movements of the brown water snake (Nerodia taxispilota)

Mark S. Mills1, Chris J. Hudson1, and Howard J. Berna1,2

1University of Georgia, Savannah River Ecology Laboratory, Aiken, SC 29802, USA, and
Department of Zoology, University of Georgia, Athens, GA 30602
2Department of Biology, Mercer University, Macon, GA 31027, USA

Abstract: We used mark-recapture techniques from August 1991 through September 1993 (52 sampling days) to study habitat use and movement of Nerodia taxispilota. We captured 411 individuals and estimated a linear density of 43 individuals/km of river habitat. River sections exhibiting the highest number of captures were clustered within 200 m of backwater areas; brown water snakes were not randomly distributed and were significantly associated with the steep-banked outer bends of the river and availability of potential perch sites. Recaptured individuals (n = 50) reaffirmed this habitat association by remaining in or moving to straight sections and outside bends of the river (90% of recaptures) with steep banks (88%) and a moderate to abundant concentration of perch sites (86%). Most recaptured N. taxispilota (70%) were found <250 m from their previous capture site, but six moved >500 m, and three moved >1 km. Ten of 11 individuals that moved >10 m/day between captures did so from 12 August through 15 October, indicating a possible seasonal movement pattern. Distance moved by individuals was not associated with size, sex, or number of days between captures; however, only large (>80 cm snout-vent length) individuals (n = 8) crossed the river (approximately 100 m). We found significant relationships between snout-vent length of basking individuals and perch height, perch exposure, and perch substrate. This is the first published study of the spatial ecology and movements of N. taxispilota in natural populations.

Keywords: Serpentes, Nerodia taxispilota; Brown water snake; Spatial ecology; Habitat use; Movement; Mark-recapture

SREL Reprint #2042

Mills, M.S., C.J. Hudson, and H.J. Berna. 1995. Spatial ecology and movements of the brown water snake (Nerodia taxispilota). Herpetologica 51:412-423.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).