Very Busy Beavers

Mike Sevigny hikes to the edge of a muddy pond north of Seattle, Washington. He and a team of scientists lower a metal cage smeared with beaver scent into the water. This smell attracts other beavers. If one of the curious critters swims inside the cage and its feet hit a wire, a door swings shut. 

Sevigny is the wildlife manager for the Tulalip Tribes, a group of Native American tribes in northwestern Washington. Over the past six years, he and his team have captured about 300 beavers and moved them to different streams. It’s part of an effort to restore wetlands in the area. Caring for nature is a part of the tribes’ cultural heritage.

Mike Sevigny is hiking with a team of scientists. They’re just north of Seattle, Washington. They stop at the edge of a muddy pond. Sevigny lowers a metal cage into the water. The cage is coated with beaver scent. This smell attracts other beavers. The critters are curious. One follows the scent into the cage. Its feet hit a wire. The cage’s door swings shut.  

Sevigny is a wildlife manager. He works for the Tulalip Tribes. It’s a group of Native American tribes. Their people live in northwestern Washington. Sevigny’s team has captured about 300 beavers over the past six years. Then the team moves the animals to different streams. It’s part of an effort to restore wetlands in the area. Caring for nature is important to the tribes. It is part of their cultural heritage.

A beaver dam is a marvel of engineering. The animals carefully arrange their materials to block almost every part of a stream (See Inside a Beaver Lodge). Soon, the nearby landscape changes. The flow of water slows to a trickle. Over time, the water builds up to form a pond. The pond helps beavers stay safe from predators. It also provides habitat for fish, frogs, and other animals. 

The beaver pond helps the environment in other ways too, says Ellen Wohl. She’s a geologist who studies rivers at Colorado State University. Water flows into the pond quickly but takes much longer to flow out through the dam. This filters pollution, making the water safer for people and animals downstream. Slowing the flow of the river can also reduce the risk of flooding when it rains. 

The sediment beneath the pond also soaks up water. “A beaver pond is like a big sponge,” says Wohl. This stored water seeps out and feeds the stream all year. Streams without beaver dams can go completely dry in the summer!

A beaver dam is an engineering feat. The animals carefully place their materials. They block almost every part of a stream (see Inside a Beaver Lodge). Soon, the area changes. The stream’s flow slows to a trickle. Its water builds up on one side of the dam. It forms a pond over time. The pond helps beavers stay safe from predators. It also creates habitat. Fish, frogs, and other animals make homes in the pond.

The beaver pond helps in other ways too, says Ellen Wohl. She’s a geologist. She studies rivers. She works at Colorado State University. Water flows into the pond quickly. But it takes much longer to flow out through the dam. This helps remove pollution. The filtered water is safer for people and animals downstream. The dam also helps when it rains. It slows the river’s flow. So, there’s less risk of flooding.

The bottom of the pond contains sediment. It soaks up water. “A beaver pond is like a big sponge,” says Wohl. This stored water slowly seeps out. It feeds the stream all year. Streams without beaver dams can go totally dry in the summer!

Over the past century, beavers have made a comeback. But many people consider them pests. That’s because beavers sometimes build dams across roadside drainage pipes, causing the water to spill into roads. Overflowing beaver ponds can damage farms and homes. 

When that happens, wildlife scientists often step in to help. They might put up fencing to keep beavers away or find other ways to control the water level in a beaver pond. But sometimes these efforts fail. That's when scientists like Sevigny move the rodents to a stream where they can do some good.

Beavers have made a comeback over the past century. But many people think they’re pests. Beavers sometimes build across roadside drainage pipes. Their dams cause the water to spill into roads. Overflowing beaver ponds can damage farms and homes. 

Wildlife scientists often step in to help when that happens. They might put up fencing around an area. It keeps beavers away. Scientists might also find ways to control a beaver pond’s water level. But sometimes these efforts fail. That’s when scientists like Sevigny move the rodents. They’re taken to a new stream. There, they can do some good.

People started relocating beavers in the late 1940s. The first ones were flown over forests and dropped from planes with parachutes! Today, Sevigny’s team moves beaver families by car to streams where beavers haven’t lived in a long time. 

The beavers quickly get busy building their new homes. Over the next few years, Sevigny’s team checks on the animals using hidden cameras or drones. “We can see how what started out as a simple stream has been changed by the beavers,” says Sevigny. “They’re incredible critters, and they work for free.”

People started moving beavers in the late 1940s. The first ones were flown over forests. Then they were dropped from planes with parachutes! Today, Sevigny’s team moves beaver families by car. They’re driven to new streams. They’re ones where beavers haven’t lived in a long time. 

The beavers quickly get busy building new homes. Sevigny’s team checks on the animals for a few years. The team uses hidden cameras or drones. “We can see how what started out as a simple stream has been changed by the beavers,” says Sevigny. “They’re incredible critters, and they work for free.”