Millions of birds cross Washington at night

By the numbers: In just one day this week, about 156,000 birds crossed the state, while about 500,000 were in transit, per the site.

• Not all birds fully cross a region in one night, resulting in a greater number of birds in flight.
• During peak migration, more than 1 billion birds can be moving across the U.S. in a single night.

Zoom in: Around 70% of migratory birds, including most songbirds and shorebirds, travel at night to avoid predators.

Yes, but: That nighttime journey comes with risks. Bright city lights can disorient birds and increase the chances of deadly window collisions.

Light pollution is the greatest threat to nocturnally migrating birds around the world, experts say.

How to help: Lights out, Washington advises turning off outdoor lights, keeping lighting dim and warm-colored and using it only when needed.

The bottom line: A simple flip of a switch can help protect birds passing overhead.