​​​2 Minutes in the Yellowstone Ecosystem
Episode 7: Swainson's Hawks   
25 May 2018
Masters of migration, Swainson's Hawks connect our Yellowstone ecosystem with one over 6,000 miles away in Argentina.

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JENNY>> Welcome to Two Minutes in the Yellowstone Ecosystem, sponsored by the Yellowstone Wildlife Sanctuary. Now here’s your host, Gary Robson:

LES>> Okay. So tell us about the Yellowstone Wildlife Sanctuary and the Greater Yellowstone ecosystem.

GARY>> Well, remember about six weeks, seven weeks ago, we talked about the Sandhill Cranes coming back after their big migration.

LES>> Yes.

GARY>> Today, I figured we’d talk about one of the real masters of migration, the Swainson’s Hawk.

[Swainson’s Hawk call]

LES>> Okay.

GARY>> These guys, you’ve seen them around, but you might not have noticed, because they look a bit like a Red-Tailed Hawk. They’re about the same size, a little more slender, lighter weight, bigger wingspan, though. These birds live around here and up into Canada in the summers, and they spend their winters in Argentina.

LES>> Ah, okay!

GARY>> So they will fly — the ones around here will put in about 6,200 miles every fall. It takes them about two months, so they’re averaging about 100 miles per day. And then 6,200 miles coming back.

LES>> That is a long ways!

GARY>> And these guys, like I said, are about the same size as a Red-Tailed Hawk, so that’s a pretty good-sized bird. When they’re nesting, when they’re feeding their chicks, they’re eating the usual 3 R’s of raptor prey: rabbits, rodents, and reptiles. But when they’re migrating — this is where they get their nickname — they go for the super high-protein food, their absolute favorite food, they switch to an insect diet and eat grasshoppers. So you may have heard these called “grasshopper hawks.”

LES>> Now that, I have not.

GARY>> Their migration is really a sight to see. They call them “kettles” of hawks when they’re migrating, and they’ll come together in kettles of ten thousand, twenty thousand birds. For the first half of their trip, they’ll actually migrate with the Turkey Vultures.

LES>> And then they’ll kind of leave them by the side?

GARY>> The vultures drop off in northern Mexico and spend the winter there, and the Swainson’s Hawks just keep on going.

LES>> See, there’s a bird on my hat?

GARY>> You have a vulture on your hat, as a matter of fact!

LES>> Yes, T.J. just got back from the Grand Canyon, and I’m assuming that’s where some of those…

GARY>> That’s where some of those Turkey Vultures go. Exactly! Or even farther south than that.

[Side note: Vultures that live in the southern U.S. tend not to migrate, and the vultures from the northern U.S. will leapfrog over them, going farther south into Mexico.]

GARY>> Our Swainson’s Hawk at the Yellowstone Wildlife Sanctuary — her name is Hawkeye — like many of our other animals, was injured. Can’t live in the wild any more, can’t migrate, so we had to do some special habitat design for her, give her a heated area where she can hang out during the winter. We have some special things we built to block the wind coming in there and give her a nice warm little corner to hang out in.
These guys are a great example of how the way you deal with wildlife in one ecosystem can affect another one far away. Swainson’s Hawks went through a dramatic population decline back in the 1970s when they were spraying DDT on the farms down in Argentina — the same stuff that almost killed off our national bird, the Bald Eagle, here in the United States.
LES>> Yes.

GARY>> And here we are six thousand miles away and it was affecting our hawk population because they were using DDT in Argentina.

LES>> Whoa. Man, oh man, the things you learn! It’s all a part of the Yellowstone ecosystem, and of course if you want to find out more, listen every Wednesday with Gary.

[Swainson’s Hawk call]

JENNY>> Thanks for joining us for Two Minutes in the Yellowstone Ecosystem, sponsored by the Yellowstone Wildlife Sanctuary in Red Lodge, Montana. This podcast updates every Friday on iTunes, YellowstoneEcosystem.com, and the Sanctuary’s website, YellowstoneWildlifeSanctuary.org.

Thanks to our recording partners at FM99: the Mountain, where you can hear this show live every Wednesday at 8:22 a.m.

I’m your announcer, Jenny Van Ooyen, and I hope you’ll join me next week for another episode of Two Minutes in the Yellowstone Ecosystem!    

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