A high intensity bird migration is expected to have 50,000 birds per square mile flying over parts of Pennsylvania tonight.
According to BirdCast, areas near Pittsburgh and Harrisburg will experience the highest volume of birds in the sky. The best time to see the birds is around 7 p.m.
The migrating birds include orioles, warblers, sparrows and tanagers and September is peak time for migration. All of the birds migrate at night.
Overall, about 900 million birds are expected to fly over parts of Pennsylvania, making it one of the heaviest migration periods of the fall.