MYSTERY OF THE MISSING MIGRANTS | © Charley Harper Art Studio | Used with Permission

Showcasing the spectacle of bird migration

When, where, and how far will birds migrate? How many birds passed last night? Our tools help you explore the answers to these and many other questions about bird migration.

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Migration tools


Explore nightly migration data in your region.  Learn more

Bird migration forecast maps show predicted nocturnal migration 3 hours after local sunset and are updated every 6 hours. Colorado State University and the Cornell Lab of Ornithology currently produce these forecasts.
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Search with our local migration alert tool to determine whether birds are passing overhead near your city tonight!
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See real-time analysis maps of intensities of actual nocturnal bird migration, as detected by the US weather surveillance radar network between local sunset to sunrise. Cornell Lab of Ornithology currently produces these maps.
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Recent news

By Carley Eschliman (Cornell) and Kyle Horton (CSU AeroEco Lab) Guest Authors Jun 15, 2024

As a reminder to what the team is working on here at BirdCast, we return to a previous post we wrote. With spring soon arriving and preparations for migration underway, here is a primer on what we do. We turn weather radar data into information on the numbers and flight directions of birds aloft in order to expand the understanding of migratory bird movement. After several years (and hundreds of posts) describing migration, species on the move, and unique migration events, we want you to have a better understanding of what happens at BirdCast. Here is a brief overview and a behind-the-scenes look at the ways we apply radar data to study bird migration.  Read more

Forecast and Analysis
By Andrew Farnsworth The Cornell Lab Apr 09, 2024

Spring migration is in full swing, and knowing when peak migration will occur in your area is valuable information! Here we provide a sortable table of peak periods of spring bird migration for the largest cities by human population size in the contiguous US.  Read more

By Andrew Farnsworth The Cornell Lab Apr 08, 2024

BirdCast will monitor ‘live’ the behavior of birds and insects during the total eclipse today. BirdCast’s ‘live migration maps’ will be enabled all day, and we have tuned the sensitivity to display the day-time activity of birds and insects combined. The eclipse display, the thumbnail you see to the right, will be active from 1pm to 5pm today.  Read more

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NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center

Lights Out

Every spring and fall, billions of birds migrate through the US, mostly under the cover of darkness. This mass movement of birds must contend with a dramatically increasing but still largely unrecognized threat: light pollution.

BirdCast Partners and Support

BirdCast is a consortium of interdisciplinary researchers, primarily from three organizations at present, with a growing list of collaborators, supporters, and partners.  Learn more

Core partners

Core funders

Other support

Lights Out partners