BirdCast provides live and local bird migration alerts throughout the continental US by employing real-time analysis of bird migration traffic as detected by radar. You can use this tool to determine whether birds are migrating in your area tonight in low, medium, or high densities. Find your area among the featured cities in the drop down menu or using the search bar! Besides providing curious birders information on local migration and where and when to go birding, these alerts serve an important conservation need. They can provide timely information about nights of high intensity migration (otherwise referred to as peak migration), only a handful of which occur throughout a given season. This allows effective targeting of the most important migration nights in a season, helping determine when to act for maximal effect of conservation actions such as turning off lights when birds are flying at night to avoid luring them towards artificial light and potentially fatal hazards.
Colorado State University and Cornell Lab of Ornithology currently produce and maintain these alerts. Migration alerts are expressed in units birds/km/night, indicating the cumulative number of birds that fly within a night across a one kilometer line transect on the earth’s surface oriented perpendicular to the direction of movement of the birds.