Total birds

2300 Birds have crossed Cook County so far tonight (est.)

Starting: Wed, Nov 12, 2025, 4:30 PM CST

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Live migration traffic

1,200 Birds now in flight (est.)
Direction: —
Speed: —
Altitude: —
Recorded: Thu, Nov 13, 2025, 1:30 AM CST
Direction, speed, and altitude cannot be reliably determined when the number of birds in flight is low.

Here's what's happened so far tonight...

Birds in flight

Tonight, Nov 12
Historic
6 PM CST9 PM12 AM3 AM6 AM013K

Birds usually begin to migrate 30 to 45 minutes after sunset, with the greatest number in flight two to three hours later.

Flight direction and speed

6 PM CST9 PM12 AM3 AM6 AM

Birds tend to migrate southward in autumn, but seasonal timing, weather, and geography alter their flight directions and speeds.

Altitude

Tonight, Nov 12
Historic
6 PM CST9 PM12 AM3 AM6 AM03000 ft

Migrating birds regularly fly up to 10,000 feet above ground, although seasonal timing and weather conditions dramatically impact their distributions.

Note: Direction, speed, and altitude may be unreliable when the number of birds in flight is low. In such cases, chart data may include gaps.

And so far this season...

Birds in flight (nightly avg.)

Fall 2025
Historic
AugSepOctNov0600K

During fall migration, most birds pass through the contiguous U.S. from early September through October.

Total birds crossed

Fall 2025
Historic
AugSepOctNov090M

This is the estimated total number of birds that have fully crossed this region. The curve rises quickly during peak migration and levels off at the end of the season.

Expected nocturnal migrants

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Nocturnally migrating species most likely to arrive or depart this region at this time of year, based on frequency of observations

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Cornell Lab of Ornithology
Colorado State University
UMass Amherst