When it comes to bird feeders, there's a pecking order — and 'size really matters'

Story Transcript

As birds flock to feeders and compete with each other for seeds, a group of ornithologists have discovered that the feathered creatures follow a pecking order. 

Citizen bird watchers across Canada and the United States have been diligently reporting their observations to the Cornell Lab of Ornithology's Project FeederWatch since 1987, describing which species swoop into their backyards and chase one another for a spot on the feeder.

Now, the Cornell ornithologists have computed that data to create a hierarchy and determine which species rule the roost.

"One of the big take-homes was that size really matters," ornithologist Emma Greig, leader of Project FeederWatch, told As It Happens host Carol Off.

"The top bird that we were able to see at feeders was surprisingly the wild turkey ... They're enormous, so of course they're at the top."

Turkeys rarely show up at the feeders, but birdwatchers reported those few and far between sightings to Project FeederWatch, so the large birds made it to the top of the list.

More often, the next big birds at the feeders are American crows. After them comes grackles, blackbirds, blue jays and even some woodpeckers.

"I think that a lot of folks would say, 'Oh, well of course [woodpeckers] are [high up] because you see them bossing around other birds all the time,'" Greig said. "It's kind of nice how the data really match up with ... our intuition about these hierarchies."

Woodpeckers are one of the smaller birds that are more aggressive than expected for their body size, the ornithologist said.

But there are other small and feisty birds, like chickadees, that rank low on the pecking order.

"They just aren't big on the fights," Greig said. "They get out of the way when someone comes along."

Although fight isn't quite the right word. While the birds may look like they're brawling, Greig says the motivation behind each species making a dash for sustenance is based on their unique displacement behaviours.

That means when one bird makes its way to the feeder, and another bird moves out of the way, they're not fighting, but rather showing who has more power.

"That's a real important piece of it. Nobody wants to get hurt," Greig said.

Instead, there are predictable relationships between the different species that help them decide how to interact.

"Even though it sounds aggressive, they're actually ways that the birds coexist with each other, kind of peacefully."

At the same time, it can get dangerous when big flocks of birds bustle to the seed feeders. Greig said goldfinches, for example, vie for the spotlight and do, indeed, end up fighting with each other.

"Sometimes the birds that you're going to be fighting with the most are your closest relatives, which maybe won't come as a huge surprise to us," she said. "We feel that way too, sometimes, as people don't we?"

Outside of the birds and their newly-discovered pecking order, the data told ornithologists of another animal — a predator — that can show up at feeders and send all the birds flying away.

"The squirrels," Greig said. "They're just a different beast. They're enormous. They have teeth.... They're even predators of young birds, so the birds [have] got to get out of the way when squirrels show up."

Written by Mehek Mazhar. Interview with Emma Grieg produced by Sarah Cooper.