Black-crowned night herons have been spotted on the island at Nature Boardwalk at Lincoln Park Zoo as recently as Tuesday. While a few herons resting in the trees from time to time pales in comparison to the rambunctious colony that made its home at the site last year, these occasional visitors are of interest because they represent a new development.

In previous years we didn’t observe herons coming through this late in winter. The birds we have been observing recently are juveniles. This makes sense because juveniles tend to leave after the adults to head south at the conclusion of the breeding season. Maybe the late arrival of the herons at the pond has to do with the particularly mild weather we’ve been having.

In Illinois, black-crowned night herons are known to stay through the winter on occasion, although it is rare. We can’t say if these birds are sticking around or if they’re heading south with a rather late start.

To look for the juvenile black-crowned night herons, scan the trees on the east side of the island in the pond at Nature Boardwalk. They tend to perch there. You can recognize them by their brown plumage with white spots, which is lighter on their undersides. They’re approximately the same size as adult birds, and they tend to assume a hunched-over posture with their beak tucked into their feathers like the bird in the photo above.

With spring now only a few months away, we’ll soon be watching for the much-anticipated return of the heron colony. We expect their return in late March or early April. Stay tuned for more information on these endangered birds as we monitor their population throughout the seasons.

Vicky Hunt