SREL Reprint #2540

Nocturnal activities of post-breeding Wood Storks

A. Larry Bryan, Jr.1, Joel W. Snodgrass1,2, John R. Robinette3, James L. Daly1, and I. Lehr Brisbin, Jr.1

1Savannah River Ecology Laboratory, PO. Drawer E, Aiken, South Carolina 29802, USA
2Department of Biological Sciences, Towson University, 8000 York Road, Towson,
Maryland 21252-0001, USA
3U.S. Fish and Wildlife Service-Savannah Coastal Refuges, 1000 Business Center Drive, Suite 10,
Savannah, Georgia 31405, USA

Abstract: Postbreeding season activities of Wood Storks (Mycteria americana) were examined during 24 h long observation periods at inland impoundments and a coastal roost site. Storks were present at inland impoundments and foraged more at night there than at other times of the day. Wood Stork attendance at the coastal roost site was significantly reduced during nocturnal low tides than during daytime low tides or at either period of higher tide levels. Presumably, storks were leaving the roost to forage on fish concentrated in tidal creeks by dropping tides. Nocturnal foraging in freshwater and estuarine systems may be an advantageous strategy for the tactile-feeding storks by reducing the likelihood of their being observed by their prey and possibly by reducing competition with other wading birds. Also, some prey species in both freshwater and saltwater environments are more active nocturnally than diurnally, this increasing their likelihood of capture by nocturnal-foraging Wood Storks. In the coastal setting, low tide events (two per ~24 h) typically provide at least one "pulse" of stork prey in draining tidal creeks during the nocturnal period.

SREL Reprint #2540

Bryan, A. L., Jr., J. W. Snodgrass, J. R. Robinette, J. L. Daly, and I. L. Brisbin, Jr. 2001. Nocturnal activities of post-breeding Wood Storks. The Auk 118:508-513.

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