Date of Award

2019

Document Type

Honors Thesis (Open Access)

Department

Colby College. Biology Dept.

Advisor(s)

Catherine Bevier

Second Advisor

Justin Becknell

Third Advisor

Manuel Gimond

Abstract

The Black Racer (Coluber constrictor) is a large-bodied snake species found across North America. One subspecies, the Northern Black Racer (C. constrictor constrictor) is listed as endangered in Maine because of its restricted range in York County. Racers have generally been found to prefer open habitats and ecotones, but the specific habitat preferences of racers in Maine is unknown, hindering efforts to preserve habitat for racer conservation. To address this knowledge gap, the Maine Department of Inland Fisheries and Wildlife (MDIFW) has an ongoing project tracking black racer movements in Sanford and Kennebunk, Maine, and I had the opportunity to participate in this research. Over the summer of 2018, I collected point locations for radio-tracked snakes and recorded the predominant vegetation at each location. Behavioral observations were conducted by following select individuals for periods of one to two hours. To explore genetic differences between sub-populations, DNA was extracted from ventral scales taken from catalogued individuals and amplified for previously developed microsatellites. I found that the black racer population at Kennebunk Plains prefers open successional fields with dense cover provided predominantly by sweet fern and Rubus spp. Racers display strong anti-predator behavior and make use of trees and forests to flee predators. The dual importance of both fields and forests for racer conservation is thus emphasized. Racers roamed on average 77.3±46..1 meters per day and generally did not show differences in roaming behavior across individuals or throughout the tracking season. Racers at Kennebunk Plains made heavy use of rip-rap, presenting the possibility of creating human-mediated habitat to supplement natural areas. Initial genetic analyses did not reveal any stark differentiation between sub-populations.

Keywords

telemetry, habitat, microsatellite, MDIFW

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