Climate change threatens birds migrating along Great Lakes

Sep 6, 2016

Some of the migratory songbirds that pass through the Great Lakes region are already on the move, and volunteers at the Braddock Bay Bird Observatory are preparing for them.


 

Hundreds of species – swallows, finches, warblers and more -- visit the observatory on the shore of Lake Ontario, just west of Rochester.

Today, the volunteers are repairing large nets, about 12 feet high with very fine mesh. That’s how they catch the birds.

"When they're flying along, they kind of hit these soft nets and fall into little pockets or hammocks," says education director Andrea Patterson.
 

Andrea Patterson inspects a common yellowthroat in order to determine its age and sex during the banding process.
Credit Veronica Volk

Volunteers take measurements and estimate the birds’ age, and put on a little numbered band so other sites can identify them.

They also record when different types of birds show up -- and Patterson says they’re noticing some changes.

“Magnolia warblers are -- the first arrival is on average about two days earlier," Patterson says. "Lincoln sparrows -- the average arrival is about four days earlier. And that might not sound like much, but that's one day every six years, and that's going to add up over time.”

And, it’s not just those species.

"Almost across the board we see that birds are arriving earlier," says Marshall Iliff of Cornell University’s Department of Ornithology. He heads up the website E-bird, where recreational bird watchers record data about what species they see, when and where.

The birds are arriving earlier, because they’re reacting to climate change.

"We're certainly in an interesting period in terms of climate," Iliff says. "Things are changing quickly, not only warming, but becoming more variable."

Warmer temperatures prompt the little travelers to start their migrations early. And even a couple days difference can disrupt a delicate natural balance and put entire species at risk.

Take the Blackpoll warbler for example.

Each fall, this tiny bird takes off from its breeding grounds in the Boreal forests of Canada and flies 4,000 to 5,000 miles to South America. The birds weigh little more than a pair of nickels but they can fly hundreds of miles non-stop.

They have perfectly evolved to be in sync with their environments. So when the timing shifts, the birds might not have a place to make their home, or enough food to feed their hatchlings.

Birds aren’t the only species affected. But scientists are studying them as an early indicator of the threats of climate change.

For Patterson, holding a bird like the Blackpoll warbler connects you to not only the animal but to the environment in a really powerful way.

“I remember going to Norway and standing on a train platform where my ancestors emigrated from," she says. "I thought about them getting ready to leave and never return.

"But the entire warbler species packs up and heads to a place where most of them have never been to and they hope that there's something good for them when they arrive but more and more often, there isn't.”