Date of Graduation

5-2023

Document Type

Thesis

Degree Name

Bachelor of Science in Biology

Degree Level

Undergraduate

Department

Biological Sciences

Advisor/Mentor

DeGregorio, Brett

Committee Member/Reader

Davidson, Fiona

Committee Member/Second Reader

Lewis, Jeffrey

Committee Member/Third Reader

Magentti, Brenda

Committee Member/Fourth Reader

DeGregorio, Brett

Abstract

Mesopredators, such as the raccoon (Procyon locor), Virginia opossum (Didpelphis virginiana), and striped skunk (Mephitis mephitis) play crucial ecological roles as predators, prey, and disease vectors across much of the United States. Because of their importance and the way that populations of these mesopredators can dramatically increase due to human-subsidized resources, it is imperative that studies attempting to quantify mesopredator community composition are accurate and unbiased. However, it has recently been suggested that not all mammals trigger motion-activated wildlife game cameras at the same rate and for some species detection probability may be biased. My goals for this thesis were to 1) conduct a field experiment to explore potential detection bias of motion-triggered game cameras in relation to common mesopredators and 2) understand how reported results in the game camera literature may be influenced by this potential bias. I did this through a two-step approach. First, I simultaneously deployed side by side infrared motion-triggered game cameras and time-lapse cameras to compare the detections of mammals acquired by each. If certain species fail to reliably trigger motion cameras, I predicted that those species would be missed by the game camera while at the same time they would be documented by the time-lapse camera that is set to take photographs at 5 second intervals with no motion-trigger. Next, I conducted a systematic review of published game camera literature and compared community composition of mesopredators as determined by three approaches: by nonbaited game cameras, by baited game cameras, or by traditional research methods (track plates, trapping, roadkill surveys, hair snares, etc). This comparative analysis explored the potential detection biased quantified in experiment 1 over a larger spatial scale and across additional species.

Analysis for experiment 1 yielded animal size as the only driving factor for motion detection probability, while there were no significant factors driving timelapse detection. Conducting analysis on the literature for experiment 2 yielded modest results; out of the 9 mesopredators collected with each paper, only opossum and coyote were affected by capture method. The findings of this study suggest that smaller animals could require bait for infrared detection, while larger mesopredators are generally unaffected by detection method.

Keywords

Mesopredators; Game Cameras; Wildlife; Raccoon; Opossum

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