A Hit Three Years in the Making

Northern Saw-whet Owl. March 19, 2023. Photo by Dustin Weidner. This photo was taken using best practices for ethical owl photography.

On April 6, 2024 at 9:40 p.m., a little owl sporting a uniquely coded radio transmitter pinged the antenna tower atop the Ford Calumet Environmental Center (FCEC) at Big Marsh Park. The Northern Saw-whet Owl, a.k.a. Owl 496, continued their journey north, travelling by the Ryerson Conservation Center antenna at 11 and registering on the Lake Petit, Wisconsin receiver at 11:30. The owl was travelling at a brisk 40 mph or more.

The antennas at Big Marsh, Ryerson, and Lake Petit are all part of the Motus Wildlife Tracking System. Motus, which is Latin for “movement,” is an international network of researchers, organizations, and volunteers using automated radio telemetry to record the flight paths of thousands of individual migratory animals over vast distances. The data collected by the network become part of a centralized, public database that contributes to research and conservation planning for species and habitats throughout our hemisphere.

The Big Marsh tower is the result of a collaboration between the Chicago Park District and COS. October 22 marks the third anniversary of installing eight antennas on the roof of the FCEC and connecting to the Motus network. 

Former COS Board member Dan Lory recalls early discussions about a possible Motus project at Big Marsh: “Conservation is a huge part of the COS mission. We saw being part of the Motus network as a way to advance that mission and at the same time grow our impact in the Calumet region.” He notes, “with the Big Marsh tower project, we are helping out scientists who are exploring the mysteries of bird movement and identifying the crucial habitats that birds rely on throughout their lifecycles.”

The data from the Northern Saw-whet Owl’s “fly by” the Big Marsh antenna was downloaded by Lory, who shared it with Motus, where it was accessed by Michael Avara. Avara is the Avian Lab Manager at the University of Illinois’ Ward Laboratory. He leads the team that tagged Owl 496 in November 2023 as part of a project to track the numbers and movement of the species. One of the few owl species that migrates, the Northern Saw-whet Owl breeds in the northern forests of the Great Lakes and Canada and can be found in Illinois over winter. Because they rarely vocalize outside of breeding season and tend to roost in dense understory, these elusive birds are difficult to track and study during migration and while wintering. The radio transmitter tags and Motus receivers help the research team gather information on the owls’ unpredictable migratory routes, and behavior in winter habitats.

Avara manages a Motus network of more than 30 towers across Illinois and Mexico. He notes, “the information automatically collected from the telemetry towers gives us much more detail on individual bird movement than simple banding and recapture.” The radio transmitters also make it possible to track and record the birds’ presence and daily activity, roosting behavior, and vocalization response.

Avara continues, “When we know more about bird migration, and the habitat birds rely on to eat and rest during their journeys, we can make smarter decisions about conservation and land management. We can better protect migration corridors and breeding and wintering habitats for all birds, but especially species at greatest risk.”

Owl 496 is only the first individual to be recorded by the Big Marsh receiver, but we expect the data will grow as more individual birds are tagged with the specialized transmitters. Avara notes, “Our team deployed 45 Motus tags on Wood Thrushes across the state earlier this year, and we hope to pick them up as they migrate through our area this fall.”

You can read more about the Motus network here and learn more about receivers around the globe, including the antennas at Big Marsh, on this map. For more on the University of Illinois research on the Northern Saw-whet Owl,  check out this webinar presented by Avara and hosted by the University of Illinois extension.