Beavers have returned to Evanston’s North Shore Channel after 10 years.

Staff at the Evanston Ecology Center, 2024 McCormick Blvd., discovered trees with fresh chewing marks and a dam along the bank of the canal last week, said Claire Alden, environmental educator at the center. Beavers disappeared from the area during the construction of waste tunnels underneath the canal in the 1990s, she said.

“It’s exciting for us because it just shows the overall improving health of the canal,” Alden said.

Beavers are known to increase biodiversity and cleanliness in their habitats, she added. The ones at North Shore Channel could be beaver babies in nearby areas starting their own families, Alden said.

“Either there’s an old couple and they had to rebuild a house that got damaged, or this might be a new couple establishing a new kind of territory,” she said.

Alden said she had also discovered creatures such as kingfishers, herons and water insects that cannot survive in polluted environments, other signs the canal’s health has improved.

She said she invites Northwestern students to participate in the center’s canoeing programs to take a close look at the wildlife.

“I’ll show them exactly where the dam is,” she said.

– Jia You