Ornithologists think a glitch in a gene that controls migration in Tropical Kingbirds causes them to fly in exactly the wrong direction. From their Arizona breeding grounds, they head northwest in fall, rather than southeast to their usual wintering haunts in Mexico. Learn more at Cornell…

Not only do Cackling Geese sound different, but they also look different from Canada Geese, and their DNA is different. The Cackling Goose was defined in 2004 as a species separate from the Canada Goose.