Check the conditions for the best spring migration flights during May 2021 for reference to future years (Great Crested Flycatcher photo by Paul Konrad) A BirdCast radar image depicting the peak migration the night of May 14-15.

Which days did you find the most new migrants in your birding area last spring? You might imagine that the biggest nights of spring migration, which include extended flights of hundreds of millions of birds, would be spread out over the course of the spring season. But, as it turns out, the primest migration nights during the 2021 spring migration, when the most birds flew north at once, were concentrated into just 2 groups of nights, and the biggest night of all was May 14-15, when it is estimated that 700 million birds flew north across the continental United States!

The 5 biggest migration nights for last spring took place overnight on May 1-2 and May 2-3, and 2 weeks later during the nights of May 13-14, May 14-15, and May 15-16. The biggest night of spring migration was May 14-15, when it is estimated that 700 million birds flew north! In fact, the May 14-15 migration was widespread across the continent was recorded as the largest single-night migration of birds since BirdCast began monitoring migrations. Combine this historic night migration with the fact that the number 2 migration night preceded it, and the number 5 migration night followed it, and you have the ultimate trifecta migration period of the spring! And that 3-night extravaganza will be hard to beat. What did your birding lists look like the days after the top 5 night migrations?

For more information about the Top 5 Spring Migration Nights, and to learn more about how BirdCast can help your birding activities throughout the fall by providing migration forecasts, see https://birdcast.info/news/migration-update-the-top-5-flights-in-spring-2021/