Seasonal roost selection of wild turkeys at their northern range edge

Wild turkeys Meleagris gallopavo are diurnally active birds that spend the dark hours roosting in trees. We tested the hypothesis that multiple benefits exist for roost tree selection by wild turkeys, including thermoregulation, resource acquisition, and protection from predators. We compared 48 roost trees used by eastern wild turkeys M. g. silvestris in Ontario, Canada to 48 non-roost trees sampled contemporaneously during 2017-2019 to determine roost site selection between seasons. Mean (+/- SE) roost tree height (21.4 +/- 0.8 m) was taller than non-roost trees (18.2 +/- 0.8 m), and roost trees were also larger in diameter at breast height (58.1 +/- 5.5 vs 38.7 +/- 3.1 cm). Using ibuttons to collect microclimate temperatures at the tree, we found that mean temperature (+/- SE) of a deciduous roost (14.5 +/- 0.1 degrees C) was higher than temperature at either a coniferous roost (13.9 +/- 0.1 degrees C) or ambient temperature (13.2 +/- 0.1 degrees C) during the summer months. In winter however, we did not find any relationship between temperature and tree type. Roosts were closer to buildings (150.8 +/- 26.0 m) in the winter compared to summer and year-round roosts, and winter roosts were also farther away from crops (395.2 +/- 63.7 m) compared to roost sites used year-round. Summer roosts were closer to roads (143 +/- 36.3 m) than the roosts in the winter and roosts used year-round. Our data suggest that thermoregulation is not the driving force behind roost selection; instead, predator avoidance appears to play the most important role, with some weaker evidence in support of proximity to resources.