If you look to the skies tonight in Eastern Pa and New Jersey, you’ll see THOUSANDS of birds flying overhead as they migrate south. More importantly, however, you may want to turn off your lights to help those birds safely migrate.

Because we're legit talking about THOUSANDS of birds flying overhead tonight.

According to BirdcCast, more than 41,000 birds per square mile could be flying south over Philadelphia by 7 pm on Monday. Tonight's migration is a significant uptick as the number of birds forecasted overhead later this week is lower in our area.

As our pal Philly ChitChat reminds us, if you’re in a high rise: TURN OFF YOUR LIGHTS. Birds are drawn to the glow of city lights, so darker skies will help prevent birds from colliding with buildings and other structures.

The Cornell Lab of Ornithology says that 1 om 4 bids have been lost since 1970.

How do we know this many birds will be migrating overhead tonight, by the way?September is the peak season for migrating birds as they head south from temperate North America to more tropical latitudes, the National Audubon Society says. 

So how do we know that tonight will be very busy? Well, in short, this data is tracked by scientists.

The BirdCast model, which is a project of the Cornell Lab of Ornithology, Colorado State University, and the University of Massachusetts Amherst, is based on forecast models tracking 23 years of bird movements. Plus, the movements of birds can be tracked by weather radars.

By the way, you can sign up to receive alerts from the BirdCast project for when high numbers of birds are passing through the area. It can act as a reminder for when you'll want to turn off your lights.