CHICAGO (CBS) — As birds begin migrating back north this spring, many will end up injured or killed as they fly through downtown Chicago, and volunteers at a suburban wildlife center will try to nurse the survivors back to health.

Migrating birds by the hundreds will hit downtown skyscrapers this spring, and many that survive will be taken to an animal rehabilitation center at a DuPage County Forest Preserve in Glen Ellyn.

“We work with a group that are in the city, that pick up the migrating songbirds that hit the skyscrapers,” said Sandy Fejt, education site manager at the Willowbrook Wildlife Center in Glen Ellyn. “We take in about 3,000 birds a year from that group.”

On the busiest days, approximately 400 injured birds might be brought to Willowbrook.

“After a storm, they’re kind of coming on the back end of a storm. So it’s kind of interesting. We all watch the weather, and we watch the winds, and that will kind of tell you what our day’s going to be like,” Fejt said.

Living halfway between Willowbrook and the city, Fejt said she drives into Chicago to pick up injured birds, and has brought as many as 230 back to the center in a single morning.

Bird migrations come in waves, and the spring bird migrations end in mid-May, according to Fejt.