Most American Robins don’t fly south for winter. Those that summer in Canada will migrate to the US, and some southern birds will go down to Mexico, but for the most part they stay right where they are. Sort of. You’re probably thinking Well, I don’t see them in the winter so they must migrate, right? Nope, they’re still here, they’re just less conspicuous. When the ground freezes, their primary food source, worms, become difficult to get so they set out from the cities into the country in search of fruit and insects. When the ground thaws, they return in droves to their favorite yards to announce the official start of spring once again.