Spring arrives at the Garden with a flourish of blooms, but this year, many eyes are fixed on an 80-foot pole rising toward the sky. Atop it sits a hexagonal platform, built for a threatened species in Illinois.

It was late April last year when a pair of ospreys were spotted on the platform nest for the first time since it was installed in 2016, in partnership with the Friends of the Chicago River and the Forest Preserves of Cook County. It is viewable from the North Branch Trail near Dundee Road.

Now, as the earth awakens from winter, the question looms: Will they return?

“We are hopeful for another pair,” said Peter Nagle, managing ecologist, lakes and shorelines. “Some data suggests that once a pole is occupied it tends to have a nest the following year.”