Welcome back, otter

A river otter, a harbinger of cleaner waters and a healthier environment, has appeared for the first time in more than 100 years in the headwaters of a Chester County creek in the Delaware River watershed, according to a conservation group.

The re-emergence of the otter in the headwaters of Ridley Creek signals a triumph of habitat restoration, said the group, the Willistown Conservation Trust. Otters serve as indicators of ecosystem health and contribute to overall biodiversity and ecosystem resilience, it said.

“This exciting development marks a significant milestone in regional conservation efforts and underscores the importance of protecting natural habitats for wildlife,” the trust said in a statement. “The return of river otters to the Ridley Creek watershed is a sign that conservation efforts in the region are having a positive impact on the overall ecosystem.”

So far, one otter has been spotted, in December, on Pennsylvania Game Commission cameras, according to the trust. Videos show an otter looking at the camera and undulating its elongated, sleek body amid a thicket of brush and branches.

River otters were present in most waterways across North America before the arrival of European settlers. As a result of widespread fur trapping and habitat destruction due to human development, otters disappeared from waterways across most of Pennsylvania by the early 1900s.

However reintroduction efforts in the 1980s led to a population rebound in northern Pennsylvania, the trust said.

It described the otter’s reappearance in the headwaters of Ridley Creek as “a monumental event” as these animals are “highly sensitive to pollution and habitat degradation and require healthy water conditions.”

Parts of the Brandywine-Christina basin, which includes parts of Chester County, are stressed by pollution or substandard conditions, according to a 2022 Pennsylvania Department of Environmental report, which found 873 miles of streams were impaired for aquatic life, 248 miles were impaired for recreational uses and 192 miles for fish consumption. Read more here.

The trust, which has been working to protect open space and restore habitat in the headwaters of the Ridley, Crum and Darby Creek watersheds since 1996, said the arrival of the otter coincides with the recent acquisition of the 90-acre Kestrel Hill Preserve in the Ridley Creek watershed.

That property was saved from development and permanently protects a critical piece of the otter’s habitat.

“Wildlife in Pennsylvania belongs to all Pennsylvanians and the return of the river otter in the Keystone State is a direct result of conservation-minded people working together to better their community by restoring, first their environment, which then translates to the wildlife that call it home,” said Tom Keller, the Pennsylvania Game Commission’s furbearer biologist. “This is a great example of a community caring about a watershed and a species responding to that passion and dedication.”

In addition to being indicators of healthy ecosystems, river otters play an important role in the environment. As a predator, they regulate prey populations. Their foraging and den building behaviors modify habitat structure for other wildlife and their presence in the ecosystem influences community dynamics.