The black-crowned night heron in flight (via Wikimedia Commons)

Last year, the Chicago History Museum (CHM) began an ambitious project on its 4.5-acre grounds in Lincoln Park. But the renovation had a consequence: It ruined a breeding ground for the black-crowned night heron, an endangered species in the state of Illinois.

In 2021, the museum broke ground on the new Richard M. and Shirley H. Jaffee History Trail, which would circle the institution and include eight stops focused on “aspects of Chicago’s personality,” highlighting pivotal moments of the city’s history such as the Great Chicago Fire of 1871. It would also include a renovated underground storage facility and the planting of native trees.

The birds’ endangered species status forced the museum to seek a permit from the Illinois Department of Natural Resources (IDNR) before it began construction, which the CHM quickly obtained.

“At that time, we had no records of black-crowned night herons at the museum, and the applicant made no indication that herons are known to nest on the museum grounds, so we terminated the consultation without recommendations,” Jayette Bolinski, the communications director at IDNR, told National Geographic. The outlet also reported that although the museum mentioned the existence of herons in its IDNR application, it did not make the vital disclosure that its grounds were a breeding site. IDNR opened an investigation, but found that there was not enough information and the offense was not criminal.

But by this year the breeding grounds, which already had empty nests, were rendered useless when male herons were unable to find mates and abandoned the museum.

The Chicago History Museum (via Wikimedia Commons)

The existence of the herons at the museum should come as no surprise — Illinois’s largest black-crowned night heron colony (with over 600 birds) is in the Lincoln Park Zoo, just down the park from the Chicago History Museum. After construction began, the herons left their museum habitat and relocated to the zoo, a space the museum sees as an extension of its own.

“The presence of BCNHs in our corner of Lincoln Park is an extension of the birds’ primary space in Lincoln Park, near the zoo,” a museum spokesperson told Hyperallergic. This year, the zoo’s Urban Wildlife Institute reported 400 hatchlings, the most since it began its observations in 2010.

“I initially thought, ‘Well, it’s a quiet time at the rookery,’” conservationist Amy Lardner of the Chicago Black-Crowned Night Heron Project told National Geographic. “But as time passed, I was seeing fewer and fewer adults and hearing no chicks. I knew by the middle of May that things were not on track.”

A museum spokesperson told Hyperallergic that the institution would “collaborate and look to them [the Urban Wildlife Institute] on improvement efforts or necessary next steps,” but no heron-specific plans have been announced.

Elaine Velie is a writer from New Hampshire living in Brooklyn. She studied Art History and Russian at Middlebury College and is interested in art's role in history, culture, and politics.