It's maple syrup time at the River Trail Nature Center in Northbrook

Families learned that a sure sign of spring's arrival is sap dripping from sugar maple trees during the "Sap's Rising" event Saturday at River Trail Nature Center in Northbrook.

Brian Winters, the center's interpretive naturalist, took socially distanced groups of two dozen people at a time, in both morning and afternoon sessions, into the woods and showed them the trees, how they were tapped, and how the sap was collected. He also discussed the history of the trees and maple syrup.

"It's been a tradition at River Trail Nature Center for many decades to help interpret the making of maple syrup as a way to help celebrate the return of spring," Winters said. "If you don't hear the birds chirping, or there's no flowers growing and the snow is still clinging desperately to the ground, people need a sign of spring right about now."

The event is tentatively planned for 10:30 a.m. and 1:30 p.m. Saturdays and Sundays through March 28. Call (847) 824-8360 for more information.