(Lewis, Iowa) — A high-tech bird-tracking system is helping Iowa researchers better understand the long journeys of migratory songbirds — and the findings could play a critical role in species conservation.
John Lorenzen, with the Iowa Department of Natural Resources in Southwest Iowa, mentions that this is not a DNR program. The network, called Motus (Latin for “movement”), uses a series of passive antennas across North and South America to log birds equipped with tiny radio tags. These tags emit a signal every two seconds, and when a bird passes within range of one of the antennas, it’s recorded.
Iowa has approximately 30 of these antennas, including one at the Harrison County Conservation Board’s nature center, which forms part of a much larger international effort. As Lorenzen says, this is not a DNR program; however, they have been using the collected data since 2021. The information collected showed 607 detections of 340 individual birds, representing 39 different species in Iowa.
One of the key species the DNR is focused on is the Wood Thrush, a songbird whose population has declined by about 60 percent since 1970. The Iowa DNR has partnered with researchers to track these birds, which are listed as a Species of Greatest Conservation Need in 25 states, including Iowa.
To study them, scientists use mist nets and audio lures to safely capture and tag birds before releasing them. Early tracking results show that many Wood Thrush migrate between September 20 and October 11, with Iowa-tagged birds later appearing on antennas in Texas, Mexico, Guatemala, and Belize.
One of the most surprising discoveries involves a Motus station in Belize, which picked up two Wood Thrushes initially tagged in Iowa, along with birds from a broad swath of North America — including Missouri, Ohio, Pennsylvania, Georgia, and even Canada.
Researchers say this indicates the Belize station sits in a critical migratory corridor, underscoring the importance of protecting habitat far beyond state or national boundaries. Conservation efforts in Central America, they say, may have a direct impact on how well Wood Thrush populations rebound in Iowa and across the U.S.
With the help of this growing network, scientists hope to fill in more of the puzzle — and give songbirds a better chance at survival.
