09/04/2026
Right now is peak fall migration in North America. Here's what's happening above you tonight:
THE SCALE: On peak nights in September, hundreds of millions of birds are aloft over the continental US. Warblers, thrushes, vireos, orioles, tanagers, sparrows, flycatchers. Most migrate at NIGHT (cooler air, fewer predators, more stable atmosphere, and they can use stars for navigation).
THE ALTITUDE: Most nocturnal migrants fly at 1,000-3,000 feet. Some go much higher.
THE SOUND: Migrating birds make "night flight calls" — short, high-pitched chips used to maintain contact with the flock and possibly to communicate about altitude and direction. Go outside at 11 PM-2 AM on a clear night in September. Stand in a dark spot. Listen upward. You will hear them. Thousands of tiny "tseep" and "zeet" calls raining down from an empty-looking sky.
THE THREAT: Artificial light at night disorients migrants. Birds are drawn toward lit buildings, circle them until exhausted, and collide with glass. Up to a billion birds die from building collisions annually in the US.
WHAT YOU CAN DO TONIGHT:
Turn off unnecessary outdoor lights (especially upward-facing). Close blinds on lit interior rooms. Support "Lights Out" programs (many cities have them — Chicago, NYC, Philadelphia, Houston, Dallas, and others).
Check BirdCast.info — it shows LIVE migration radar. You can see how many birds are flying over YOUR county tonight.
Go outside. Turn off the porch light. Look up at nothing. And listen to a river of birds passing overhead.
