Author: Kaj    Overturf

Major: Biology & Wildlife Ecology

Graduation Year: 2019

Thesis Advisor: Erik Blomberg

Description of Publication: Populations at a species’ northern range extent are often presented with more challenges than those in more southern regions, given that winters are generally harsher, and the reproductive season is shorter in these northern regions. Wild turkeys (Meleagris gallopavo) are near their northern range limit in Maine, and there have been no studies that have researched turkey roosting here. Wild turkeys roost in trees at night, and we predicted that roost selection would be affected by changing weather conditions, particularly during winter when temperatures are expected to be coldest. We also predicted that land cover composition would affect roost site selection due to spatial variability in food availability. We captured and GPS-tagged wild turkeys in Penobscot County, Maine, to analyze their selection for four forest attributes during roosting: tree height, basal area, softwood percentage, and distance to forest edge. We also explored the potential for wind chill, precipitation, or land cover composition, particularly human development or agricultural land, to have moderating effects on selection. We used resource selection functions, implemented as generalized linear mixed models (GLMMs), to evaluate attributes of used versus available roost sites and considered interactions between weather and land cover. We found evidence to support selection across all habitat characteristics. The effects of wind chill and precipitation on roost site selection were not supported, while land cover effects were. Our results suggested that either a factor potentially linked to land cover that we did not consider, such as predation risk, has a greater effect on selection than weather, or that wild turkeys in our study area had access to sufficient food resources to not be forced to select primarily for thermal cover when roosting.

Location of Publication:

URL to Thesis: https://digitalcommons.library.umaine.edu/honors/571