The annual fall migration of birds across the United States has continued this week, with millions of birds traversing the state of Illinois just in the last 24…
The annual fall migration of birds across the United States has continued this week, with millions of birds traversing the state of Illinois just in the last 24 hours., nearly 8.5 million birds crossed Illinois between Monday night and Tuesday morning. At the peak of the migration, more than 13.5 million birds were estimated to be in flight over the state, according to BirdCast data.
BirdCast also provides data not just on how many birds have traveled across the state, but when they do the majority of their flying during the migration season. According to that data, birds typically begin to migrate 30-to-45 minutes after sunset, with peak numbers seen approximately two-to-three hours later, usually between 10 p.m. and 12 a.m.