The effects of drought on foraging habitat selection of breeding Wood Storks in coastal Georgia

Foraging habitat use by Wood Storks (Mycteria americana) during the breeding season was studied for thr ee coastal colonies during a drought year and compared to habitat use during normal rainfall years. Information on the distribution of wetland habitat types was derived using U.S. Fish and Wildlife Service National Wetland Inventory (NWI) data within a Geographic information System (GIS). Foraging locations were obtained by following storks fi-om their colonies in a fixed-winged aircraft. Differences in hydrologic condition and, the resulting prey availability in coastal zone freshwater wetlands greatly affected foraging habitat use and breeding success of the three stork colonies. In 1997 (dry), although the foraging range of each colony did not differ from wetter years, storks used estuarine foraging habitats much more extensively. Breeding success (fledged young/nest) in 1997 was less than half the success of the wetter years. Palustrine (freshwater) wetlands seem very important to storks breeding along the Georgia coast. During dry years, estuarine wetlands, by themselves, do not appear to be able to support the breeding population of storks in this region. Reasons why these productive wetlands do not provide sufficient resources for successful breeding are unclear, but could include limitations to only two foraging periods (low tides) in a 24-hr period.