The FWS uses avian radar to monitor bird and bat migration along the shorelines of the Great Lakes (http://www.fws.gov/radar/). Since 2011, mobile avian radar units have been stationed around each of the Great Lakes during the spring and fall migration seasons to track birds and bats as they fly. By using avian radar to study migration, data can be gathered over a much larger area without causing stress to the animals being studied. Additionally, the avian radar units can collect data continuously and during times when visual surveys are difficult, such as at night. The radar units gather data about the flight direction and height of the migrants. Data from the avian radar units are combined with acoustic and ultrasonic monitors and information from visual bird surveys to answer a variety of questions about the dynamics of migration. Data and information derived from this project along with the FWS Voluntary Land-Based Wind Energy Guidelines will help inform decisions to balance the needs of development with the need to protect wildlife.
A summary of more than 18,000 targets tracked within 1 hour at a site on Lake Michigan during a fall night in 2011. Tracks are colored according to their direction of movement, most moving south and colored red, orange, or yellow. The night sky is certainly not empty during migration!