Date of Award

2020

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dr. Shane Welch, Committee Chairperson

Second Advisor

Dr. Jayme Waldron

Third Advisor

Dr. Anne Axel

Abstract

The change in the interaction between southern fox squirrel (Sciurus niger niger) and eastern gray squirrels (Sciurus carolinensis) provided an opportunity to examine sublethal effects of predation as it relates to a species’ risk perception and habitat structure at two scales. The interactions allowed us to examine the evolutionary responses of the southern fox squirrel and eastern gray squirrel to predation risk reflective of their historically associated landscapes and habitat structures. Second, the succession of savanna woodlands into closed-canopy mixed forest provided an opportunity to assess the flexible behaviors of both species in response to changes in predation risks that occur with changes in current habitat structures (e.g., predation risks that vary within a patch). In this study, we quantified the foraging behavior and risk perception of the southern fox squirrel and eastern gray squirrel by compiling an ethogram from the camera footage obtained using a feed depot and a time-lapse camera. We expected southern fox squirrel vigilance behavior would have a positive relationship with change in canopy cover (i.e., vigilance behavior increases as canopy cover increases), whereas the vigilance behavior of the eastern gray squirrel would have an inverse relationship (i.e., vigilance behavior decreases as canopy cover increases). We expected southern fox squirrels would be more vigilant compared to the eastern gray squirrel. Contrary to our expectations, eastern gray squirrels spent a greater proportion of their foraging time being vigilant than southern fox squirrels. Our results were inconsistent with our predictions that vigilance behavior of southern fox squirrels would have a positive relationship with canopy cover, whereas eastern gray squirrels would have an inverse relationship with canopy cover. We failed to detect a significant effect of canopy cover on vigilance of southern fox squirrels and eastern gray squirrels. Our results suggest that eastern gray squirrels perceived greater risk from stationary and ambush predators, for whom vigilance is an effective strategy to avoid predation, than active predators, while southern fox squirrels perceived greater risk from active predators, for whom vigilance is less effective in avoiding predation.

Subject(s)

Squirrels -- Behavior.

Squirrels -- Ecology.

Wildlife conservation.

Conservation biology.

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