This nuclear power plant has become a crocodile haven.

1.5 million bats spend their summers under a Texas bridge.

How one man finds food in every sidewalk crack.

These invaders are on the loose, and multiplying.

A sewage treatment facility becomes a birding hotspot.

A common butterfly could be an indicator of climate effects to come.

Can nature help save a city from drowning?

A highly-endangered salamander finds a home in a fast-growing city.

Doctors are now telling their patients to “take a hike”.

Coyotes have made a remarkable comeback in Chicago. What are the secrets to their survival in a dense metropolis? We hunted for clues with noted biologist Stan Gehrt.

There are two squirrel species in Chicago, and they are very particular about where they live. Gray squirrels tend to live in ritzy neighborhoods, while fox squirrels thrive in more affordable areas. A local biologist thinks he’s finally figured out why.

Less than a mile from Manhattan in the middle of the East River is North Brother Island, the former home of a notorious typhoid hospital. Today the hospital lies in ruins, and nature is taking over.

It’s been a busy few years at the Marine Mammal Center. This hospital for wild seals and sea lions has seen a record number of patients as a result of several environmental threats. We made the rounds with a veterinarian.

Chicago is a dangerous place…for migrating birds. But now scientists, architects, and dedicated volunteers are teaming up to make the city a leader in bird-friendly design and policy.

The monarch butterfly’s remarkable migration is in peril. Its habitat has been decimated by rapid urbanization and changing agricultural practices. Could cities come to the rescue?

Redwood forests can be mysterious places, but this one raises all kinds of questions. What’s a redwood forest doing in Oakland? Why do the trees grow in concentric circles? And why is one redwood so much bigger than the rest? We have the answers.

New York’s Bronx River—once an open sewer—is now teeming with life. We discovered oysters, eels, herons, and even beavers, as we canoed through the poorest congressional district in America.

They’re vacant, but not empty. We trekked through several vacant lots on Chicago’s south side, and found—amidst the discarded tires and construction debris—birds, bees, butterflies, and some very valuable plants.

We know that green roofs cool our buildings and absorb storm water. But could they also provide habitat for wildlife? To find out, we got special access to five private rooftops in New York and Chicago.

If you want to know what Chicago looked like 200 years ago, head to the city’s southeast corner. Native wetlands, forests, and prairies all come together here, at a natural crossroads.

If you take the ‘A’ train to the end of the line in Queens, you land at Jamaica Bay, where salt marshes support endangered birds and rare turtles. We patrolled these waters with an activist known as the Jamaica Bay Guardian.

In San Francisco they’re imagining a world in which cars share the road with birds, bees, butterflies, and bicyclists. We cycled a few of the wildlife corridors designated in the city’s Green Connections Plan.

What did San Francisco look like before Europeans got here? You’ll find the answer in the Presidio. This urban national park has dunes, marshes, a mountain lake, and a plant so rare we can’t disclose its exact location.

It’s a seemingly impossible task: cataloguing every wild plant species in Central Park. But that’s exactly what two botanists are doing, and they’re making some surprising discoveries along the way.

Cities once converted streams into sewers to make room for development. But now there’s a growing movement to unearth these buried waterways.