Atmospheric conditions make a world of difference on migration and bird behavior. Wind, precipitation, cloud ceiling, and barometric pressure set the stage for bird migration and can set or alter bird’s plans once it is in flight.

Many avid birders monitor NEXRAD radar data in order to predict the likelihood of it being a “good day,” which means we could be in store for a large raptor flight or passerine “fallout,” or a “good night,” where we can hear the flight calls of nocturnal migrants. Below are a few tools for monitoring weather and radar data



The term “NEXRAD” stands for NEXt generation RADar and is used by avid birders and professional ornithologists to track migratory birds.  The unfiltered image at left shows a NEXRAD image of the United States. The blue circles reflect the density of flocks of birds, bats, or insects as they migrate over a radar station, allowing us to see nocturnal migration. By analyzing looping sequences of these colorful maps, birders can reasonably forecast the density, location and direction and speed of birds during migration.

For resources on how to use NEXRAD to predict local migration patterns, click here.