In October, Bryce had the privilege of visiting the Cedar Grove Ornithological Research Station (CGORS), a long-term fall migration monitoring station along the shore of Lake Michigan in central Wisconsin. Each year, strong winds from the west cause a large number of migrants to build up along the shore as they move south. CGORS is uniquely situated to take advantage of this build up, and capture and band migrants. Although this has been a long-term site, the banding effort has provided only glimpses into where the individuals passing through this region come from, and where they go. Because of this, CGORS was interested in collaborating with the Red-tailed Hawk Project to add to our efforts to understand movement in the Great Lakes region, and gain some insight into the birds they interact with each fall.
In the end, Sue Kaehler and Danny Erickson put out four transmitters on some stunning individuals. To see these four individuals in more detail, visit the Movement Ecology page.
One individual, Otto, is fairly typical in appearance for the borealis that breed in Wisconsin. The bird currently seems to maintain a winter territory only kilometers west of the research station near Sheboygan, Wisconsin. It is likely that this bird will maintain this territory all winter, and may breed at the same location, and so opens up the opportunity for comparative work between winter territories of resident birds relative to migrants.
For instance, after being tagged, Madison moved down to Kentucky where it seems to have found a winter territory. Comparing the differences in winter territory between individuals and populations, as well as the characteristics of these locations, will give us insight into potential factors that drive differential behaviors in seasonal movements, as well as what factors contribute to a high quality wintering site. Another notable difference between these two birds is their age – Madison is a second-cycle and so may provide insight into how movements and territories may change across the annual cycle as birds age and become more experienced.
As our scope continues to grow, tagging second-cycle individuals and residents will become more important to better understand the factors involved in governing the different movement strategies between individuals and populations. We really appreciate CGORS for joining our effort and enabling us to better understand the intricacies in the life of the Red-tailed Hawk.
Special thanks to everyone at CGORS that assisted with getting these transmitters out, especially Jenn Schneiderman for her excellent holds.