Ornithologist Discusses Causes Of Bird Downings

Dec 15, 2011



They're just everywhere. That's how a wildlife manager describes the mass casualties of Eared Grebes that crash landed in southern Utah on Monday night. Some 1,500 grebes died, another 3,000 have been rescued. The small water birds were migrating and apparently mistook a Walmart parking lot, highways and football fields covered with snow for bodies of water.

To find out how common this sort of mass bird downing is, I'm joined by ornithologist Kevin McGowan. He's at the Cornell Lab of Ornithology in Ithaca, New York. Kevin McGowan, welcome to the program.

DR. KEVIN MCGOWAN: Thanks for having me.

BLOCK: Have you heard about this same kind of migratory confusion happening on a big scale like this before?

MCGOWAN: Yes, it does happen. Well, I won't say regularly, but certainly not frequently. But, yes, it does. Unfortunately, it happens on a small scale all the time. But when you get a big group of birds coming down into a place like this, that's a bit unusual but not unheard of.

BLOCK: And explain how that would happen. Why would a Walmart parking lot to be confused for a body of water?

MCGOWAN: Well, these guys are flying at night. So, they are up in the air and are usually trying to figure out which way is up, by the fact that the sky is lighter than the ground. It sounds like there was bad weather that they ran into and were trying to get down out of the air.

Then they look down and they see this wide-open, dark area that looks like it's got - it's shiny, it is reflecting the sky. Hey, that's got to be a lake. And that's exactly what they're looking for. So they went down to land in a nice glide at 40 miles an hour and expecting the waters to part in front of them and it was asphalt. That's not so good if you're a grebe.

BLOCK: You know, it's interesting because I think we assume that birds have such incredibly honed navigation skills and migration skills that something like this just really make you wonder what's gone wrong.

MCGOWAN: Well, it does. There's been a lot of natural selection to try to get their skills honed, as you say, to the point of perfection. But there's only so much perfection you can do in the natural world.

And, of course, we've thrown things into there, as people. For example, the basic idea of the sky will always be lighter than the ground. Therefore, light is up. That's great, except when you're flying over a city and it's all much lighter down on the ground. Then that doesn't work so well. And that's why moths beat themselves to death on lights and fly into candle flames and things like that. Their directional system worked for millions of years and now it doesn't because they're suddenly faced with a new situation that's quite outside the scope of their navigation system.

BLOCK: Kevin McGowan, are there lessons that you take away from this, anything that could be done to prevent something like this from happening again?

MCGOWAN: Well, we do try to look at these sorts of situations. This is rare. But, you know, if you're interested in birds and the natural world and what's going on, people do look and see. Is this something preventable? Did they - can we just shut the lights off on the parking lot? Would that have done it?

And when things happen often enough, people do take action. And there have been people who are trying to get big cities to turn off the lights in skyscrapers during peak bird migration because of exactly this kind of thing. So, there are big programs that people are out there trying to make some changes so that we don't kill a lot of birds.

And nobody wants to kill a lot of birds. That's the thing. It's like, if you know what's going on, then you'll change it. And that's why we pay attention to these sorts of things because we want to know. Are we doing something wrong or is this just a freak accident?

BLOCK: Well, I guess the good news is that a lot of these grebes were rescued and were taken to lakes nearby so that they could take off and get on their way.

MCGOWAN: Well, it was good there were so many people around who were willing to take a hand and help. These guys can't walk. They're like - well, you know, penguins - they don't walk so well. These guys don't even walk as well as penguins on the ground, so they needed some help to actually get going. And it's good that there was a good community there that could help them out.

BLOCK: I've been talking with Kevin McGowan, he's with the Cornell Lab of Ornithology, about the mass bird downing in Utah this week that left some 1,500 eared grebes dead. Kevin McGowan, thank you.

MCGOWAN: You're most welcome.


