A wildlife corridor.

Washington Department of Transportation

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Animal Crossings

Pathways built just for wildlife are making highways safer.

As You Read, Think About: How are wildlife corridors a “win-win” for both people and animals?

A hungry mountain lion steps out from a forest. In the distance, it sees a deer that it hopes will be its next meal. But a highway stands between the big cat and its prey. Cars and trucks speed by at 65 miles per hour. If the mountain lion wants to eat, it will have to risk its life to cross the busy road.

The problem this mountain lion faces is not uncommon. Across the U.S., animals big and small cross traffic in search of food, mates, or new places to live. Also, major highways and local roads cut through the migration routes that many animals follow each spring and fall.

The result has been an alarming number of accidents across the U.S. According to one study, nearly 2 million collisions took place between vehicles and animals from July 2019 through June 2020. To prevent accidents, some states have created wildlife corridors. These are pathways built under or over busy roads to enable animals to cross safely.

The U.S. has more than 1,000 of these wildlife crossings—and more are being planned.

A hungry mountain lion steps out from a forest. In the distance, it sees a deer that it hopes will be its next meal. But a highway stands between the big cat and its prey. Cars and trucks speed by. If the mountain lion wants to eat, it will have to risk its life to cross the busy road.

The problem this mountain lion faces is not uncommon. Across the U.S., animals cross traffic in search of food, mates, or new places to live. Also, highways and roads cut through the migration routes that many animals follow each spring and fall.

The result has been an alarming number of accidents across the U.S. According to one study, nearly 2 million collisions took place between vehicles and animals from July 2019 through June 2020. To prevent accidents, some states have created wildlife corridors. These are pathways built under or over busy roads to enable animals to cross safely.

The U.S. has more than 1,000 of these wildlife crossings. More are being planned.

Marina Poushkina/Shutterstock.com

LOOK OUT! A black bear and her cubs cross a road in Canada.

Over and Under

In Washington State, the I-90 highway cuts through Snoqualmie (snoh-KWAHL-mee) Pass. About 28,000 cars and trucks zoom through the pass each day. That could mean trouble for the hundreds of animal species that live in the area, including bobcats, black bears, coyotes, and elk.

In 2009, the state began building wildlife corridors along a 15-mile stretch of the highway. Patty Garvey-Darda is a wildlife biologist with the U.S. Forest Service who helped plan the corridors.

She explains that the project includes both bridges and tunnels, because different animals prefer to use different kinds of corridors. Along I-90, the crossings are planted with grass and other vegetation to help them blend in with the rest of the animals’ habitat. The goal is to make sure that creatures of all sizes regain the full habitat that was divided by the highway.

“We’re trying to connect the whole ecosystem,” Garvey-Darda explains.

In Washington State, the I-90 highway cuts through Snoqualmie Pass. About 28,000 cars and trucks zoom through the pass each day. That could mean trouble for animal species that live in the area, like bobcats, black bears, coyotes, and elk.

In 2009, the state began building wildlife corridors along a 15-mile stretch of the highway. Patty Garvey-Darda is a wildlife biologist with the U.S. Forest Service. She helped plan the corridors.

She explains that the project includes both bridges and tunnels. That's because different animals prefer to use different kinds of corridors. Along I-90, the crossings are planted with grass to help them blend in with the rest of the animals’ habitat. The goal is to make sure that creatures can use their full habitat.

“We’re trying to connect the whole ecosystem,” Garvey-Darda explains.

Courtesy of Conservation Northwest

 

ON THE MOVE: A family of Canadian geese uses an underpass on I-90.

Safer Travels

Wildlife crossings aren’t meant to protect only animals. Thousands of drivers and passengers are injured in collisions with animals each year.

Along I-90, wildlife corridors are doing their job. In 2019, fencing was put up along the highway to guide the animals to use crossings. Since then, Garvey-Darda says, not one large animal has been struck by a car.

Corridors have been a success in other places too. A study found that installing crossings along a highway in Colorado led to a 90 percent drop in collisions with moose and other large animals.

In Florida, corridors help protect endangered panthers—as well as alligators and other wildlife. In Vermont, crossings enable frogs and salamanders to travel safely each spring to breed.

Wildlife crossings protect people as well. Thousands of drivers and passengers are injured in collisions with animals each year.

Along I-90, wildlife corridors are doing their job. In 2019, fencing was put up along the highway to guide the animals to use crossings. Since then, not one large animal has been struck by a car.

Corridors have been a success in other places too. A study found that installing crossings along a highway in Colorado led to a 90 percent drop in collisions with moose and other large animals.

In Florida, corridors help protect endangered panthers as well as alligators and other wildlife. In Vermont, crossings enable frogs and salamanders to travel safely each spring to breed.

The Road Ahead

The I-90 project is about half finished, and more wildlife crossings are scheduled to be built by 2029. Garvey-Darda says this project and others like it are great solutions to help wildlife and people coexist.

“This is a win-win because not only will we be safer while we travel the interstate, but wildlife populations and ecosystems will be healthier too,” she explains.

The I-90 project is about half finished, and more wildlife crossings are scheduled to be built by 2029. Garvey-Darda says this project and others like it can help wildlife and people coexist.

“This is a win-win because not only will we be safer while we travel the interstate, but wildlife populations and ecosystems will be healthier too,” she explains.

Critter Crossings

Though much of the focus in building wildlife corridors has been on large mammals, the structures also protect smaller creatures. A wide variety of wildlife has been spotted traveling over and under I-90.

“It’s like opening a birthday gift,” says wildlife biologist Patty Garvey-Darda. “There are always surprises.” Here are a few of the animals that have been seen.

From left to right: Pine Marten; Western Toad; Pocket Gopher

RT Images/Shutterstock.com (pine marten); HWall/Shutterstock.com (western toad); Daniel Heuclin/NaturePL.com (pocket gopher)

Critter Crossings

Though much of the focus in building wildlife corridors has been on large mammals, the structures also protect smaller creatures. A wide variety of wildlife has been spotted traveling over and under I-90.

“It’s like opening a birthday gift,” says wildlife biologist Patty Garvey-Darda. “There are always surprises.” Here are a few of the animals that have been seen.

From left to right: Pine Marten; Western Toad; Pocket Gopher

RT Images/Shutterstock.com (pine marten); HWall/Shutterstock.com (western toad); Daniel Heuclin/NaturePL.com (pocket gopher)

1. Based on the article, what are some reasons a wild animal might try to cross a highway?

2. What is a wildlife corridor?

3. How did scientists in Washington State guide wildlife to use the animal crossings they built along the I-90 highway?

1. Based on the article, what are some reasons a wild animal might try to cross a highway?

2. What is a wildlife corridor?

3. How did scientists in Washington State guide wildlife to use the animal crossings they built along the I-90 highway?


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