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.

Learn how


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.
Learn more

Search with our local migration alert tool to determine whether birds are passing overhead near your city tonight!
Learn more

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.
Learn more

Recent news

By Victoria Simons Colorado State University Sep 16, 2022

Aeroecological research is more than simply studies of bird migration. Victoria Simons is studying how Tree Swallow foraging behavior relates to their usage of airspace as habitat.   Read more

By Carolyn Burt Colorado State University Sep 16, 2022

To inform the public on threats from light pollution to migrating birds, Colorado State University's Dr. Kyle Horton and his collaborators are hosting a virtual seminar series this fall entitled, “Transdisciplinary perspectives on artificial-lights-at-night and achieving sustainable night skies.”  Read more

By Andrew Farnsworth The Cornell Lab Aug 01, 2022

With much anticipation, the BirdCast team welcomes you to our Fall 2022 season! Our migration tools are now live, so please feel free to explore!  Read more

All news

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