Hundreds of millions of migrating birds flying over Chicago on their way south

Nearly 300 million birds flew over the Chicago area on Wednesday night. Another 276 million are expected to make the same trip Thursday night.

But their remarkable journey south comes with a danger: Chicago's skyline. There are some simple things you can do to help these birds make it south safely.

"It is a big time for migration right now," said Annette Prince, director of Chicago Bird Collision Monitors.

Specifically, approximately 296 million birds flew over the Chicago area on Wednesday night.

The First Alert Weather team said there was too much moisture in the air to spot them on radar, but that might change Thursday night.

"Sometimes, whenever it's a clear night and we have a lot of birds moving through, the radar can pick it up as clutter, and it looks like rain, when in reality it's just those birds moving on through," meteorologist Shane Hinton said.

Another 276 million birds are expected to make the trek across Chicago on Thursday night, heading south for the winter, often as far away as Florida and South America.

"They're seeking food sources, really, primarily, because there's plenty of insects to eat up north in the summer, so it's great to raise baby birds when you're up in Canada, and places where there's lots of insects readily available," Prince said.

Hinton said cooler temperatures this time of year also play a role in bird migration.

"The atmosphere is more stable during the overnight hours. The birds are able to use the stars and moon to help navigate themselves, and it's more popular in the overnight hours, because it allows them to avoid any predators," he said.

As the birds soar over the Chicago area, high rises are in their migration path, and that's been a problem.

"Hundreds of calls are coming in. People are seeing them at any kind of a building where they're getting in trouble because they're colliding with glass," Prince said.

Prince said glass windows on Chicago buildings and bright lights are a bird hazard.

"They really have not enough time to evolve to adapt and realize that this is actually a dangerous place to stop and rest," she said.

There's been a push to make sure people turn off or dim lights during large bird migrations. Chicago Animal Care & Control posted a message on their Facebook page urging the public to do that with unnecessary exterior lights from 11 p.m. until 6 a.m. through Friday.

Experts also recommended removing plants from windows.

"They might see the plant as a typical piece of nature and they'll fly towards the window, so closing windows and blinds if you can," Hinton said.

That will ensure a safe path for migrating birds as they make their way through the Windy City.

When it comes to multi-story buildings, the Building Owners and Managers Association of Chicago said it is "proud of its longstanding involvement in Lights Out Chicago, a voluntary program that encourages buildings to reduce unnecessary lighting during migration seasons."

"The program has helped raise awareness and promote practical steps to reduce bird collisions across Chicago," a BOMA spokesperson added.