Each year, millions of birds travel from summer breeding areas in North America to winter in the south as far as Latin America and the Caribbean. Along their route, migrating birds face an increasingly complex range of threats, including development pressures, invasive species, avian diseases, and a changing climate. Information on migratory processes and patterns are critical to our understanding of how these threats affect migrating birds. Yet migration strategies are not well understood, particularly for smaller species because tracking these species can be difficult.
More recently, tiny tracking devices can be used for small animals. In 2012, we began investigating where Gray Catbirds, who breed in Montana, spend the winter and how they migrate. Preliminary results suggest they winter along the gulf coast, in a wintering area succinct from other Gray Catbird populations from the mid-western and eastern United States (see Ryder et al. 2011). We recently began collaborating with researchers at the University of British Columbia and Environment Canada to explore the question from a broader perspective.
To further investigate migratory patterns in songbirds, we also run banding stations during fall migration in the Bitterroot Valley on the MPG Ranch. We began running stations in 2011 to investigate phenology, species composition, molt patterns, and abundance of migrant passerines in different habitats. We are currently analyzing data related to body condition of migrating birds, as well as how stress hormones affect feather quality during the growth period. We are fortunate to be partnering with Sara Berk, PhD candidate, and Dr. Creagh Breuner, both from the University of Montana.