14-05-2025
720 million birds flew across the US Tuesday night
Bird migration typically peaks for the northern United States in mid-May, and on Tuesday night around midnight, scientists estimated that 718.9 million birds were in flight, mostly in the Mississippi Valley where a southerly breeze and dry weather helped birds move north.
BirdCast, a research consortium consisting of scientists from The Cornell Lab of Ornithology, Colorado State University and UMass Amherst, uses weather radar to estimate the number of birds and direction of flight during spring migration and produces a U.S. forecast for the night.
The site has a migration dashboard for every county in the United States. For example, Pulaski County, Arkansas, was near the peak of the migration Tuesday night when nearly 10 million birds crossed the county, mostly Rose-breasted Grosbeaks and White-throated Sparrows.
Peak migration season ranges from April 24 in Florida to May 15 in Maine. Scientists recommend turning off lights between 11 p.m. and 6 a.m. local time to avoid bird collisions.
