On July 23, 2023, the Motus antenna array at the Little Rock Audubon Center recorded its third migrating bird, a Black Tern fitted with a transmitter by a researcher at Jackfish Lake, Saskatchewan, on July 5. It was captured for a study examining their migration routes and movement among breeding colonies.
This bird left its breeding area sometime after July 12, then was detected by an antenna at Glacier Creek Preserve, Omaha, Nebraska, on July 22. To make it to the vicinity of the Little Rock Audubon Center, presumably on the Arkansas River, by the next day it had to fly at a minimum speed of 45 mph for 11 hours.
Black Terns nest on freshwater marshes in the interior of the US and Canada. By mid- to late-July birds begin their long journeys south to spend the winter along the coasts of Central or northern South America.
The Little Rock Audubon Center's Motus array is part of an organization-wide effort to better track birds at Audubon Centers. Motus, the Latin word for movement, uses radio signals and receivers to hunt birds. Small nanotag transmitters are temporarily attached to birds and other wildlife. These transmitters send a sign that a receiver can pick up along the way, specifically a Motus tower. These towers have antennas that can pick up the call from a tagged individual if they fly within a few miles of a building. Staging these towers along migration routes creates a virtual net to capture the animals' information.
The Motus wildlife tracking system is one way to monitor and visualize bird migration. Explore the annual journeys of over 450 bird species at Audubon's Bird Migration Explorer.