Date of Award

January 2019

Degree Type

Open Access Thesis

Document Type

Master Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Luke E. Dodd

Department Affiliation

Biological Sciences

Second Advisor

Charles L. Elliott

Department Affiliation

Biological Sciences

Abstract

Recreational areas represent a significant source of human-wildlife interaction, which can have an especially negative effect on organisms, like snakes, that are generally perceived as dangerous by the public. Considering the projected increase in recreation rates in the United States, the threat to this already vulnerable group of organisms deserves attention. While habitat factors associated with recreational areas—fragmentation, decreased canopy cover, altered vegetation composition—have been shown to affect snake thermoregulatory behavior and abundance, detailed studies of wild snake behavior are uncommon due to their cryptic nature. The goal of this study was to reduce human-wildlife conflict at a recreational site in Kentucky where copperhead snakes (Agkistrodon contortrix) are known to aggregate and forage. Capture-recapture data were used to 1) describe the demographic structure of the population and 2) construct models that quantify the probability of apparent survival (S) and recapture (p) as it related to snake sex and weight. In addition, copperhead foraging behavior was closely observed in order to 1) quantify individual behaviors, 2) calculate movement rates, and 3) describe the copperhead’s general foraging strategy at the site. From 2015 to 2018, 84 individual copperheads (male = 46; female = 38) were captured, weighed, and PIT-tagged. The average number of snakes caught each year ranged from 18 to 45, and the total number of captures (including recaptures) was 261. The probability of apparent survival varied 5–49%, and the probability of recapture varied 0–15%, depending on the sampling year. The greatest difference in apparent survival attributable to sex was 3% and the greatest difference in recapture was 1%. Apparent survival varied as a function of mass, 9–20% for both males and females. Recapture did not vary as a function of mass for males or females. In 2018, 72 nightly surveys were conducted to assess copperhead behavior at the study site. Individuals were observed using visual and vomeronasal cues to forage for newly emerged annual cicadas (Tibicen spp.) on the ground and in patches of vegetation and small trees. On average, snakes were non-mobile for 61.00 ± 8.44 min (59%) and mobile for 42.69 ± 7.51 min (41%). The average distance traveled during a single foraging event was 30.20 ± 6.98 m, at an average speed of 0.40 ± 0.11 m/min. The number of directional changes during a foraging event ranged from 0 to 24 with a mean of 6 ± 1 changes, and the average amount of time individuals spent climbing was 13.1 ± 4.80 min. The number of cicadas eaten per individual ranged from 0 to 3 and the average handling time was 3.17 ± 0.60 min. Based on the importance of human safety and snake conservation at the study site, these data will be used to 1) inform educational programs and resources that facilitate public understanding of copperhead ecology, and 2) reinforce copperhead conservation by implementing management techniques that reduce copperhead occupancy and allow future monitoring at the study site.

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