Amy Lardner first heard the strangled squawking sound while walking near the Lincoln Park Zoo more than a decade ago. It was the call of the black-crowned night heron, a wetland bird found throughout North America but considered endangered in the state of Illinois. Ever since, Lardner, 60, said she has been lurking near where … Continue reading The case of the black-crowned night herons: Abandoned nests reveal gaps in the state’s ability to protect endangered species