The wonder of bird migration

The Wonder of Bird Migration by Myrna Pearman

May 28, 2024 | Myrna Pearman, Chin Ridge Seeds (en-CA)

Myrna Pearman, Resident Naturalist & Backyard Bird Feeding Expert
This article is part of our "Ask Myrna" Backyard Bird Feeding Series.

Bird migration is one of the most remarkable natural phenomena on the planet. Each spring and each fall, billions of birds take to the skies. In the spring, they head northward towards their breeding grounds, making long and often arduous journeys to take advantage of abundant sunshine and a cornucopia of food, especially insects. In the fall, after raising their families, they head in the opposite direction to escape the cold temperatures and dearth of food.

During my three-plus decades as the biologist at Ellis Bird Farm, I was involved in several migration-related research projects. From bird banding to the deployment of light-level geolocators on both Purple Martins and Mountain Bluebirds, our projects helped unravel some of the mysteries and miracles of migration. We learned that Purple Martins, for example, depart their Central Alberta breeding grounds early (usually by mid-August), take their time going down to their overwintering sites in the Amazon rainforest, but then rocket back in the spring. The first Purple Martin we tracked traveled a total of 22,000 km in one year. She returned from her wintering grounds to the same box she’d nested in the previous year in only 21 days, averaging a distance of 600 km/day! Mountain Bluebirds, on the other hand, don’t travel as far south and keep the opposite schedule: they quickly make their way down to their wintering grounds in Texas, New Mexico and northern Mexico but then take their time returning north in the spring, usually timing their journey to coincide with the greening-up of the landscape.

Most recently, I have been privileged to continue contributing to migration research by having a Motus tower installed near my home at Sylvan Lake, AB. Motus (motus.org) is an international collaborative research network that uses coordinated automated radio telemetry to track migrating animals. Radio transmitters are affixed to target animals, which are then detected when they pass by specialized receivers placed on high towers. Under ideal conditions, a transmitter-bearing bird that passes within 15 km of a tower will be detected.

My system was installed by a local technology enthusiast in May, 2023 and we waited expectantly for the first “hit.” We didn’t get any spring/summer detections, but we were very excited to have some significant hits last fall.

The first bird to be picked up by my tower was a Swainson’s Thrush. The bird had its transmitter attached on August 28 at a banding station north of Whistler, BC. The bird then headed in a northeast direction, perhaps following river valleys, and passed by my Sylvan Lake tower at 5:30 AM on September 13, a distance of 651 km. It continued eastward and was detected by a tower in Red Deer a mere 20 minutes later, covering a distance of 27 km. It then headed southeast where it was detected on October 7 by a receiver in North Carolina, a distance of 3,075 km. The most exciting part of this story is that it then traveled south for an additional 2,700 km, arriving at Parc Nacional Santa Rosa, Costa Rica, on November 18!

The other detections of interest were two Northern Saw-whet Owls that passed by my tower on October 4. Each had received their transmitters at the Beaverhill Bird Observatory (BBO) east of Edmonton, AB, one September 22 and the other on September 28. Interestingly, one of the BBO’s 50 tagged owls returned from its winter migration and was detected at a tower near Pigeon Lake, AB on April 13, 2024.

I am now checking the Motus website on a daily basis, eagerly awaiting more hits as the main wave of tagged birds wing their way north. I urge everyone to check out the Motus website—which is very user-friendly and easy to navigate—to learn more about the migration patterns and journeys of our remarkable wild neighbours.

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