How Wind Circulation Patterns Impact Fall Migration of Birds

Want to spot migrating birds? Watch the weather! In the fall, wind circulation patterns around highs and lows impact the movement of migratory birds. The ideal time for flying often occurs the day after a cold front passes – northerly winds, dropping temperatures, rising air pressure and clearing skies are good migration conditions. On the West coast, easterly winds can result in large migration events. Southern California’s warm Santa Ana winds can produce large “fall-outs” of migratory birds along the coast, where thousands of birds congregate in a relatively small area. Stormy weather, overcast skies and fog can also cause large fall-outs of migratory birds, which can make for good viewing opportunities.

Tip: Learn more about migratory birds and weather from eBird, and be on the lookout for migrants passing through your area. BirdCast provides weekly regional migration forecasts with tips about what species you’re likely to see.

Spotting migrating flocks where you live? Record the birds you see and share your observations on eBird. Your observations become part of an international network generating data that can be used by educators, land managers, ornithologists, and conservation biologists.