Breakthroughs in Radar Science Reveal 4 Billion Birds On The Move

Fall migration will bring 4 billion birds into the skies over the United States. That’s not a guess—it’s hard data, gleaned from the first-ever national bird count using weather radar.

Cornell Lab of Ornithology scientists analyzed data from 143 weather radar stations from 2013 to 2017 to provide the first large-scale counts of migratory bird activity across the United States. By comparing the number of birds moving back and forth each autumn and spring, researchers also determined the average annual return rate: 76% for birds crossing the southern U.S. border, including Neotropical migrants such as warblers, tanagers, and orioles.

Your support of the Cornell Lab helps advance a whole new era of big-data ornithology as scientists use novel ways to combine radar technology and computational power to illuminate the scale of bird migration across the continents.