On its live migration map, BirdCast tracked more than 1.2 billion birds streaming south to their wintering grounds after sunset Thursday\u2014the largest single-night total ever recorded since the collaborative research project began mapping live migrations in 2018. This surge surpasses the previous milestone of one billion birds, first observed in October 2023. <\/p>\n\n\n
More Cornell Lab News<\/h2>![\"\"](\"https:\/\/www.birds.cornell.edu\/home\/wp-content\/uploads\/2025\/02\/YellowBelliedSapsucker_StevenHunter.jpeg\")
<\/figure><\/div>News Room<\/span><\/a><\/div><\/div><\/li><\/ul><\/div>\n\n\n\u201cThese numbers are almost inconceivable,\u201d said Andrew Farnsworth, a visiting scientist at the Cornell Lab of Ornithology and longtime BirdCast researcher. \u201cThey\u2019re enormous. They grab your attention, even for people that study migration regularly. The scale of how many organisms that this represents, it is just mind blowing.\u201d <\/p>\n\n\n\n
Farnsworth said this seemingly rare night captured about 10% of the continent\u2019s birds in flight at the same time. On an average fall night during peak migration, only about 400 million birds are detected in flight at the same time above the United States, but on this night, the number was three times that. \u201cIt\u2019s really unbelievable,\u201d he said. <\/p>\n\n\n\n![\"Map](\"https:\/\/www.birds.cornell.edu\/home\/wp-content\/uploads\/2025\/09\/IMG_4790.jpg\")
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While astonishing to both birders and scientists, Farnsworth said this event was not random. It resulted from a combination of ideal migrating conditions coinciding with the peak of fall migration. <\/p>\n\n\n\n
Thursday night\u2019s weather was perfect for travel, he explained, with calm winds\u2014including tail winds that helped push the birds along their migratory paths across much of the center of the country and the Mississippi River valley. <\/p>\n\n\n\n
BirdCast is a collaborative research project that uses weather radar and machine learning to track and forecast bird migration patterns, with research contributions from the Cornell Lab of Ornithology, Purdue University, University of Illinois Urbana-Champaign, and University of Massachusetts Amherst. <\/p>\n\n\n\n
Farnsworth said this record-breaking migration\u2014documented by radar technology that was never intended to track birds\u2014is a chance to not only to marvel at the immense magnitude of bird migration but also a chance to remind the public that the data is freely available and accessible in real time. The technology at BirdCast.org<\/a> allows anyone to view forecast maps that predict the number of birds migrating while live migration maps show migration happening in real time. Both tools let people know when birds are moving nearby, so they can take necessary precautions to protect them. <\/p>\n\n\n\n\u201cBirdCast gives the ability for more people to engage in and participate in this incredible spectacle,\u201d Farnsworth said, \u201cand understand that it\u2019s happening.\u201d <\/p>\n\n\n\n
It\u2019s also a timely reminder that people across the continent can help make birds\u2019 journeys safer. Every year, more than one billion birds die in collisions with windows in the United States. <\/p>\n\n\n\n
Bright lights can disorient birds migrating at night, drawing them into areas where collisions with glass are common. To help, turn off nonessential lights at night and add bird friendly film or other markings spaced no more than two inches apart on the outside of windows. Learn more at stopbirdcollisions.org.<\/a> <\/p>\n\n\n\n
<\/figure><\/div>\u201cThese numbers are almost inconceivable,\u201d said Andrew Farnsworth, a visiting scientist at the Cornell Lab of Ornithology and longtime BirdCast researcher. \u201cThey\u2019re enormous. They grab your attention, even for people that study migration regularly. The scale of how many organisms that this represents, it is just mind blowing.\u201d <\/p>\n\n\n\n
Farnsworth said this seemingly rare night captured about 10% of the continent\u2019s birds in flight at the same time. On an average fall night during peak migration, only about 400 million birds are detected in flight at the same time above the United States, but on this night, the number was three times that. \u201cIt\u2019s really unbelievable,\u201d he said. <\/p>\n\n\n\n <\/p>\n\n\n\n While astonishing to both birders and scientists, Farnsworth said this event was not random. It resulted from a combination of ideal migrating conditions coinciding with the peak of fall migration. <\/p>\n\n\n\n Thursday night\u2019s weather was perfect for travel, he explained, with calm winds\u2014including tail winds that helped push the birds along their migratory paths across much of the center of the country and the Mississippi River valley. <\/p>\n\n\n\n BirdCast is a collaborative research project that uses weather radar and machine learning to track and forecast bird migration patterns, with research contributions from the Cornell Lab of Ornithology, Purdue University, University of Illinois Urbana-Champaign, and University of Massachusetts Amherst. <\/p>\n\n\n\n Farnsworth said this record-breaking migration\u2014documented by radar technology that was never intended to track birds\u2014is a chance to not only to marvel at the immense magnitude of bird migration but also a chance to remind the public that the data is freely available and accessible in real time. The technology at BirdCast.org<\/a> allows anyone to view forecast maps that predict the number of birds migrating while live migration maps show migration happening in real time. Both tools let people know when birds are moving nearby, so they can take necessary precautions to protect them. <\/p>\n\n\n\n \u201cBirdCast gives the ability for more people to engage in and participate in this incredible spectacle,\u201d Farnsworth said, \u201cand understand that it\u2019s happening.\u201d <\/p>\n\n\n\n It\u2019s also a timely reminder that people across the continent can help make birds\u2019 journeys safer. Every year, more than one billion birds die in collisions with windows in the United States. <\/p>\n\n\n\n Bright lights can disorient birds migrating at night, drawing them into areas where collisions with glass are common. To help, turn off nonessential lights at night and add bird friendly film or other markings spaced no more than two inches apart on the outside of windows. Learn more at stopbirdcollisions.org.<\/a> <\/p>\n\n\n\n<\/figure>\n\n\n\n