More than 70,000 broad-winged hawks have crossed the Detroit River in the past week as the annual autumn migration count gets under way at Lake Erie Metropark in Michigan.
The Detroit River Hawk Watch is tracking the birds as they head south, with counters stationed at the park’s boat launch to record the number and species passing overhead.
The watch runs from September 1 to November 30, seven days a week, with a paid counter supported by the International Wildlife Refuge Alliance, the Detroit River International Wildlife Refuge and the Hawk Migration Association of North America. Volunteers also help identify birds and explain the migration to visitors.
How the Detroit River Hawk Watch counts migrating birds
Counters scan the sky for raptors including broad-winged hawks, turkey vultures, bald eagles, ospreys, falcons and other birds of prey. They record each sighting, and where possible identify the bird’s age and sex.
The site’s position near the meeting point of the Detroit River and Lake Erie makes it an important route for migrating raptors. The birds use rising columns of warm air, known as thermals, to gain height and conserve energy during their long journey south.
Data collected at the hawk watch is used to monitor population trends and assess the health of raptor species. The site has recorded as many as 16 species during the migration season, while the total number of birds seen over a three-month period has varied widely according to weather and other conditions.
The Detroit River Hawk Watch has operated since 1983, making the annual count one of the region’s longest-running citizen science projects.
