Above: Snow crust thickness (L) may impact Great Gray Owl foraging (owl snow print R). Photo Credit: TRC Staff
Although most of TRC’s field research involves observing birds in the wild, one day a month during the winter the entire team heads into the field to measure snow. One of our goals is to understand the effects of changing snow conditions on raptors. Specifically, graduate research associate Katherine Gura is studying how snow depths and snow crusts influence Great Gray Owl winter movements and subsequent breeding. During the winter, Great Gray Owls hunt small mammals beneath the snow, but deeper snow and more severe snow crusts may restrict owls’ ability to forage. These tougher hunting conditions may explain why owls periodically disperse out of the valley or forgo breeding. We’ve measured snow depths and snow crusts at owl territories across the valley for the past 8 years. Meanwhile, Gura has modeled the evolution of snow conditions across the GYE using remotely-sensed data. Using this combination of remotely-sensed and on-the-ground snow data, Gura is evaluating the link between snow conditions and owl movements and breeding.