When An Animal Goes Extinct

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I'm Iain Macleod from the Audubon Society of New Hampshire, and this is Something Wild.

One September 1, 1914, the last passenger pigeon died. Today, scientists are just beginning to learn the impact that its extinction is having on our environment - and us.

Sounds crazy, I know, that a bird that disappeared 87 years ago can affect us today. Here's how it can happen:

Passenger pigeons used to be the most abundant bird in North America. Many, many reports talked of masses of them obscuring the sun, covering the sky and being bigger than the imagination. There were between three and five billion of these birds.

Passenger pigeons ate acorns, beech nuts and chestnuts. Huge flocks of them flew up and down the eastern seaboard looking for bumper crops of these nuts. These birds were inordinately easy to catch and kill for food, feathers and fun. And that's exactly what people did, until there simply weren't any left.

What does this have to do with us? Well, one theory suggests the passenger pigeon used to out-compete other species, namely the white-footed mouse and white-tailed deer, for food supplies. With the pigeon gone, these two species flourished, and their populations have grown exponentially. At the same time, the incidence of Lyme disease, almost non-existent before the end of the last century, has also increased dramatically.

But what's really interesting is that locally, Lyme disease increases dramatically two years after an especially good nut crop. Putting two and two together, the theory now goes that the two vectors for Lyme disease, the mouse and the deer, are benefiting from the abundant food supply now available. As they benefit, their parasites also benefit. More deer, more mice, more ticks, more Lyme disease bacteria, more sick people.

Extinction happens, but when it does it sets off a complicated chain of events that can have very direct ramifications for us- which is why saving every species can be important.

For Something Wild, I'm Iain Macleod.