Warnings issued as millions of birds expected to cross Illinois – NBC Chicago

More than four million birds passed through Illinois Saturday night into Sunday morning, with more expected in the coming days as the annual spring migration of birds continues over the United States.

According to Birdcast, an average of 11.2 million birds were in flight during the night hours since Saturday.

This trend is expected to continue Monday and Tuesday evenings, with officials expecting “high levels” of migratory birds to fly over the state. You can find a bird migration map here.

“You can observe and listen to their movements day and night,” said a warning from Birdcast. “Remember that high-intensity nocturnal migration does not necessarily mean an excellent birding day; rather, it means that large numbers of birds are migrating or predicted to migrate at night.”

Thousands of birds are killed every year during migrations when they strike buildings and power lines, with experts urging the public to take steps to protect their health and safety.

Officials advised residents to protect nocturnal migratory birds by turning off non-essential lighting from 11pm Monday to 6am Tuesday morning.

“Every spring and fall, billions of birds migrate across the US, usually under the cover of darkness,” according to Birdwatch. “This mass movement of birds must contend with a dramatically increasing, but still largely unrecognized, threat: light pollution.”

Residents were also asked to allow cats indoors as the animals are more active at night when hunting for prey.

During spring migration, an estimated 313 million birds crossed Illinois as they traveled north to Wisconsin and Canada, Birdcast said. The birds will stop often in Illinois on that trip, providing wonderful shows for bird watchers across the state.

According to Birdcast, several species of warblers, including the Yellow Warbler and the Nashville Warbler, migrate north through Illinois along with Baltimore Orioles and several other species.