2 minute read
Bird Surveys
During the spring of 2021 when amphibians were actively breeding, biologists conducted auditory surveys to identify male anurans advertising to females. Each frog and toad species has its own unique call that it uses to attract females during the breeding season. Biologists listened for calling anurans for ten minutes at 45 points in the Preserve between 30 minutes after sunset and midnight (Figure 7). Biologists recorded all frog and toad species heard calling, and assigned an activity index for each species heard based on methods outlined in the North American Amphibian Monitoring Program (US Geological Survey 2016). In addition to the activity index and species heard, we collected data on weather variables, including air temperature, wind speed, humidity, moonlight, and car traffic.
During the summer of 2021, WEST conducted aquatic surveys in Griffy Lake using fyke nets to trap and release turtle species. Fyke nets use a funnel and cone structure to bait and trap aquatic species within the net. WEST placed three fyke nets in Griffy Lake; one net was placed east of north Headley Road in a ponded area that connects to Griffy Lake through a culvert, and two nets were placed on the north side of the lake within two inlets (Figure 7). Biologists placed flotation devices within the traps to allow air holes for turtles, and baited the traps with canned cat food to attract turtle species. Biologists checked traps for three consecutive mornings in early August, 2021. We used waders and a small fishing boat to check traps and identify turtle species caught in the nets.
Figure 5. Call surveys target amphibian species actively breeding at night, like American toads.
Figure 6. A fyke net placed in Griffy Lake to capture and release turtle species.
Bird Surveys
WEST conducted bird inventory surveys year-round at the Preserve, from September 2020 to August 2021. Surveys consisted of avian counts of bird use around fixed observation points following methods similar to Reynolds et al. (1980). We selected ten observation points, known as survey locations, in the following plant community types in order to get a representative survey of bird species in the Preserve: mesic sloping woodlands, dry mesic wooded slopes, dry mesic ridges, wet- mature mesic woodland on limestone ridges, mesic floodplain forest, emergent wetlands, mudflats, wet old field, and open water (community types adapted from Tungesvick 2019; Figure 8). Biologists surveyed each location for ten minutes, twice per month. Biologists recorded the date, start and end time of the ten-minute observation period, survey location point number, species (or best possible identification), number of individuals, sex and age class (if possible), distance from observer when first observed (meter), activity, and habitat/vegetation type.
Figure 7. Herpetological survey locations in the Griffy Lake Nature Preserve, Monroe County, Indiana.
