For Bird Researchers, A Breakthrough In Tracking Migration
Researchers have a new way of tracking the song sparrows, dark-eyed juncos and other birds that fly about the Laurel Highlands.
Some species eventually make their way across Canada, while others head elsewhere in the United States or farther south in the winter to the warmer skies of Latin America.
Traditionally, researchers seeking to track bird migration attached an identification band to a bird’s leg and hoped that someone, somewhere would find it. That day might come when the bird died, and a person who stumbled upon its body noticed the band and reported the information it contained back to wildlife officials.
“We made these incredible discoveries with banding and it still is an incredible tool, but when it comes to figuring out where birds go, it’s pretty inefficient,” said Luke DeGroote, avian research coordinator at the Powdermill Nature Reserve.
The Powdermill staff would band 10,000 birds a year, only to recover two or three.
That changed in 2016 after DeGroote heard about the Motus tracking system.
Developed in Canada, there are now 400 Motus stations in North and South America. Researchers set these antennas up to detect tagged birds that fly within a several-mile radius.
Of the 50 birds tagged using Motus transmitters in Powdermill’s first year, 40 percent have been detected across the two continents.
How Motus Works
Motus stands for "movement" in Latin.
The first step is to catch a bird.
That was what the organizers of a recent workshop at Powdermill set out to do in the early morning hours. They held a training for researchers from across the Americas who wanted to learn about the Motus technology.
The staff opened up nets to catch birds passing by. DeGroote also cleared some snow off a table to put down several metal cages.
“I shoveled it off, and am going to pour some bird seed to draw them in,” he said.
An hour later, a few birds had already walked into the cages and taken the bait.
Indoors, workshop participants watched DeGroote apply a tag to one of the birds.
Each transmitter about the size of a fingernail, with strings that stick out to broadcast a radio signal. It’s attached to a little harness made from elastic sewing thread.
“We’re going to put the birds’ legs through those loops and it’s going to fit over that knob that the birds have on the leg,” DeGroote explained to the group. “It’s going to sit on the rump, kind of like a fanny pack.”
Later, in a field nearby, workshop participants attempted to set up one of the antennas.
Bob Frey from Klamath Bird Observatory in Oregon struggled to drive a metal anchor into the wet ground.
“It’s being difficult, but it’s going in,” he said.
What Researchers Hope To Learn
Frey worked on the anchor alongside Pablo Elizondo, executive director of Costa Rica Bird Observatories.
Elizondo plans to put up five Motus stations this year, the first on Cerro de la Muerte, or the Hill of the Dead. He said it should really be called the “Hill of Life” because it’s home to many of the 83 bird species that live exclusively in the highlands of Costa Rica and Panama.
“It’s extremely relevant for us to deploy this kind of technology because it will allow us to track movements on some of those resident species that we know very little about,” he said. “For some of these species, we don’t even know if they move or not between seasons.”
Plus, there are only a handful of Motus stations in Latin America compared to North America, yet many birds fly back and forth across the entire region. They include the Swainson’s thrush, the species Frey wants to study in Oregon.
“It’s a really cool little bird,” Frey said. “It’s got a beautiful song, very flutelike.”
The bird spends at most a few weeks in Oregon each year to fatten up before continuing its migration.
“We’re hoping using this Motus system that we’ll be able to describe very precisely within a meter or so where that bird is,” he said. “We’ll be able to go out and do vegetation surveys and see where that bird has been foraging, where it’s been seeking shelter.”
The Swainson’s thrush population is in decline. Information on it and other species collected through the Motus system helps researchers identify threats to birds and better conservation practices.
DeGroote said Powdermill is using Motus to find out what happens to birds that hit windows.
Some people think that when a bird survives a collision, it's OK when it flies off.
“There are other people who say no it has a concussion, with all this awareness about football players and boxers, and that this is going to have some sort of long-lasting effects, either immediately or possibly down the road,” he said. “That’s what we’re trying to figure out.”
The truth is probably somewhere in the middle, DeGroote said. It’s important to pinpoint because it will help determine just how severe a problem windows are for birds and promote ways to retrofit windows to prevent those collisions.