By Jim Armbruster – Research Coordinator
Addison County Vermont is the place to be for birders. Its mix of unique habitats draw hundreds of birds and bird watchers alike. In the winter it is known for being home to several migratory artic species including Rough-legged Hawks, Snowy Owls, and thousands of Snow Geese.
Other species also call this area home in the winter including Red-tailed Hawks. Red-tails are known to be partial migrants in Vermont. Birds from the northern parts of their range will move south for the winter. The timing and length of their travels are reliant on several factors. These migratory birds may displace residents that are migrating themselves or may leap frog areas with a resident until they find a suitable spot for the season. Some Red-tails remain residents in Vermont year round. Some may leave the state entirely. The migration strategies are well known but their use of this region is less studied.
The goal of our winter raptor ecology project is to determine how Red-tailed Hawks are using the habitat in Addison County. We will look at the timing of their migration, movements in relation to changing weather conditions, and abundance in relation to prey availability. We also hope to find the relationship between migratory and resident Red-tails that will coexist for the winter season and potentially the relationship between Red-tails and other similar species like Rough-legged Hawks.
To accomplish these goals we will map the size of our ten study birds home ranges through the winter to determine what factors drive the size and location. We will mount radio telemetry trackers on eight of our study birds and then relocate them throughout the winter.
We are also partnering with researchers from Cornell in their Red-tailed Hawk Project to mount GPS trackers on two birds. This data will aid in our project and help their researchers to look at the breeding success of Red-tails throughout their entire range.
Next winter we hope to partner with researchers from The Idaho Cooperative Fish and Wildlife Research Unit in their Rough-legged Hawk Project. This will include mounting GPS transmitters to Rough-legged Hawks while they are in Vermont for the winter. The transmitters will provide year round movement data for those birds.
The data collected this winter can be used to build the framework for more studies in this area. GPS trackers on all our birds can give us a year round look at their movements. We can determine where exactly these winter migrants are coming from and where they end up once in Vermont. Several seasons of data can be used to look at other factors influencing their decisions. Other species like Rough-legged hawks can be added to the study to look at the relationship between two similar species that share the same habitats in the winter.
Stay tuned for more updates from the field!
We live near the Basin Harbor club in West Ferrisburgh. I can tell you we reliably see a Red Tail Hawk perched on tree branches hunting the open fields on Basin Harbor Road past where it crosses Dead Creek. We also always see one on Button Bay Road perched in the tree tops every time we drive by, south of the State Park. There are a number of Osprey platforms around but I never see hawks using them. If you want to direct folks on where to see Red Tails, send them there..
We will have to check those spots out!