Each year, since I was a little kid, my mom and I take guesses about when we will see the first robins of the year.
Now that I live in northwest Iowa and she lives in eastern Iowa, she usually sees them first, so I usually guess earlier than I would expect to see them here.
However, sometimes people will see a robin in the middle of winter and think spring is on its way. That’s not quite an accurate predictor, because robin migration can be quite varied. Here are some fun facts about robin migration.
1. Some robins don’t migrate.
American robin breeding grounds are throughout Alaska and most of Canada, but they also spend time year-round throughout the vast majority of the U.S. On their range map (click here), the only specifically overwintering grounds for the robin is in southern points of the U.S. and Mexico.
If there are robins around you in the winter, you might not see them, because they spend more time roosting in trees and less time looking for food in your yard like they would during breeding season.
Some robins also just move as far as they need to in search of fruit. They might move a little bit and then have to fly a bit farther south when they need a more abundant supply of fruit and then fly a little farther south when they need more food.
2. Robin food loves 37-degree temperatures.
As ground thaws in the spring, robins begin to dig for earthworms and insects. It is because of those food sources that robins tend to start showing up, or at least becoming more visible to human populations, when temperatures hit 37 degrees. It is not that robins themselves like that temperature but because their food does. Robins migrate in response to food more than to temperature.
Robins also eat different meals at different points in the day. Have you ever heard the phrase, “The early bird catches the worm”? In the morning, robins eat more earthworms, and by afternoon they switch to fruit.
3. Singing is key.
Marking where robins are first sited in the spring can be confusing because of the factors above. Robins that are spotted might not be birds that are migrating north and instead might be birds that are overwintering.
The biggest key to spotting robins that are migrating to their breeding grounds is singing. American robins typically don’t sing — there are exceptions — until they arrive at their breeding territory because a song is the way that male robins defend their territory.
It just sounds like spring, doesn’t it?