Last year I had the pleasure of meeting Dr. Malle Carrasco-Harris at the International Urban Wildlife Conference (#IUWC2019). Carrasco-Harris has been studying the role urbanization plays in the behavior of Eastern Copperhead snakes (Agkistrodon contortrix) and while we might not think of snakes as congruent with cities, multiple species of snakes have been able to survive in the remnant urban green spaces.
Previous research on birds and mammals has shown that within urban parks, forests, and green spaces these taxa have behavioral plasticity, leading to smaller home ranges and increased population density. However, this behavior hasn’t been readily studied in reptiles– and, in particular, snakes. The Eastern Copperhead lives across the eastern United States and exhibits seasonal site fidelity, making them more susceptible to landscape modifications. Additionally, previous research has shown that urban snakes may have poorer body conditions than their rural conspecifics.
To examine the role urbanization plays in Eastern Copperhead behavior and body condition, Carrasco-Harris captured 217 individuals and used radio telemetry to track a subset of 44 individuals. Study sites included Overton Park, an urban forest located in Memphis, Tennessee, and the Meeman Field Station located in Shelby County, Tennessee. The 57 ha urban forest (Overton) has been isolated by roads, residential buildings, and commercial areas for the past century and contains extensive public trails. The rural forest (Meeman) is bordered by forests and woody wetlands with low traffic roads and few buildings.
Carrasco-Harris et al. found that urban copperheads have significantly smaller home ranges than rural copperheads and that urban snakes tended to move less than rural snakes (figure 1). They also found no difference in body condition however, urban snakes tended to be smaller than rural snakes indicating that urban copperheads may have decreased reproductive ability.
This research shows that urban Eastern Copperheads follow similar behavioral trends as urban mammals and birds, with reduced home range size, less movement, and smaller bodies. This empirical research is essential as we continue to investigate how urbanization influences the behavioral ecology of native species.
Read the study:
Featured image: Peeking out is “Hooty”, a copperhead that remained in a root hole in a manicured section of Overton Park, Memphis, Tennessee, for the month of July 2015. The hole afforded Hooty the opportunity to watch cyclists, runners, and walkers on the nearby pedestrian road and a peek of the children’s playground. Hooty’s transmitter stopped sending signals the following spring, but he was once again spotted in the same hole the following July. Park users seemed oblivious to his presence. Photograph © Melissa McMasters from Urban Naturalist cover issue 35.
