Prey Selection 159 



these regional ecosystems are available (Harper 1927, Sherman 1935, 1939, 

 Moore 1949, Ivey 1959, Golley 1962, 1966, Neuhauser and Baker 1974, Sanders 

 1978, Schacher and Pelton 1979). 



In conjunction with mist netting studies relating to roost site selection 

 and habitat use of bats on Sapelo Island, Georgia (Menzel et al. 1995), we under- 

 took a comparative study of prey selection based on analysis of fecal pellet con- 

 tents collected from five species of bats captured on the island: evening bat, Nyc- 

 ticeius humeralis (Rafinesque 1818), Seminole bat, Lasiurus seminolus (Rhoads 

 1895), eastern pipistrelle, Pipistrellus subflavus (Cuvier 1832), northern yellow 

 bat, L. intermedius Allen 1862, and big brown bat, Eptesicus fuscus (Beauvois 

 1796). To determine the degree of prey selectivity by the bats from among 

 potential prey, we compared fecal pellet contents to available insects collected at 

 vegetational community types on the island where bats foraged. 



STUDY AREA 



The study was conducted on Sapelo Island, Mcintosh County, Georgia 

 from 19 June through 24 July 1995. Sapelo Island is located approximately 63 

 km south of Savannah and 5.5 km off shore (31°27'N, 81°16'W). The island is 

 approximately 16 by 3.2 km in size and is typical of barrier islands of the south- 

 eastern Atlantic Bight (Johnson et al. 1974). Seven well-defined vegetational 

 community types characteristic of regional lower Coastal Plain ecosystems are 

 present on the island (Shaw and Fredine 1956). Bats are known to forage in all 

 seven of these communities. Longleaf pine stands (Pinus palustris) are restrict- 

 ed to the northern third of the island. The remaining vegetational community 

 types are located throughout and include stands of pond pine (P. serotina), loblol- 

 ly-slash pine (P. taeda and P. elliottii), mixed pine-oak (upland oaks comprise 

 less than 25 % of the overstory), mixed oak-pine (pines comprise less than 25 % 

 of the overstory), oak stands dominated by live oak {Quercus virginiana), and 

 high marsh. Further descriptions of the floral associates of these vegetational 

 communities are provided by Johnson et al. (1974). 



The climate of Sapelo Island is characterized by long, warm summers 

 and short, mild winters. Average temperatures for June and July are 26.3 and 

 27.7 C, respectively. Average monthly rainfall for June and July is 14.58 and 

 15.65 cm, respectively (National Climatic Center 1983, Johnson et al. 1974). 



METHODS 



Capture Techniques - Bats were captured throughout the study using 3 

 x 12 m mist nets set over or near ponds in all seven major vegetational commu- 

 nity types on the island. Nets were opened from dusk until 0200 hours. Bats 

 are known to forage over dunes, marshes, and open salt water. However, no 

 effort was made to mist net in these areas. Bats netted throughout the night were 

 held in a 32-ounce cup, and fecal pellets were collected. All bats were released 



