1 6 Timothy C. Carter et al. 



within an hour, whether fecal pellets were collected or not. Data recorded from 

 bats included species, sex, and age class (juvenile or adult). Age classes were 

 determined by back-lighting finger joints to examine the level of epiphyseal dia- 

 physeal fusion (Anthony 1988). 



Insect Sampling - A variety of methods are available to sample insects. 

 All of these have inherent biases (Kunz 1988). While light traps are biased 

 toward phototrophic insects (Bowden 1982), they have been shown to be satis- 

 factory in foraging studies of bats (Taylor and Carter 1961, Brack and LaVal 

 1985, Jones 1990, Lacki et al. 1995). 



Seven, 10- watt, black light insect traps were powered by automotive 

 batteries. One was placed in each vegetational community type. Traps were sus- 

 pended from 1 to 3 m above the ground and positioned to be visible from most 

 points within a 60-m radius. Traps were operated each night between 2100 and 

 0300 hours at the same time bats were tracked using telemetry. Insects were 

 removed each night and frozen for subsequent identification. The size of the 

 insects considered to be consumable ranged from 2 to 25 mm for all bats (Gould 

 1955, Ross 1961, Black 1974, Feldhamer et al. 1995). A total of 8,753 insects 

 in this size range was identified to order, and proportions of orders present were 

 calculated. Regression analysis indicated no changes in relative insect abun- 

 dance in the respective habitat types over our sampling period. Therefore, we 

 combined data for insects in each habitat type over our sampling period. 



Fecal Analysis - Fecal samples were placed in a petri dish with 70% 

 ethanol solution and teased apart using probes and forceps (Whitaker 1988). All 

 fecal pellets collected from a single individual were examined together using a 

 dissecting microscope. To eliminate researcher bias, fecal samples were exam- 

 ined using identification numbers that were referenced to the species, age, and 

 sex of the bats. A reference collection of insects collected during the study was 

 used to help identify fecal matter (Whitaker 1988). Most insects were identified 

 to order, some to family or species. Percent volume of prey taxa was visually 

 estimated for each sample, and percent occurrence was calculated. Lepidopter- 

 ans were often only represented in fecal samples by scales. Therefore, percent 

 volume of this order was estimated using a modified version of Black's method 

 (1972), and were not considered if present in small numbers. 



Selectivity - Whitaker (1994) noted that to distinguish between oppor- 

 tunistic versus selective feeding by insectivorous bats, it is necessary to assess 

 the insect taxa available to the bats and compare these to prey items actually 

 eaten. We followed Whitaker (1994) in assessing prey taxa availability by sam- 

 pling insects in the habitats in which the bats were foraging (see below). We then 

 compared prey taxa availability in different habitats to the insect taxa found in 



