Migration of the American Robin
The American Robin (Turdus migratorius) is one of my favorite backyard birds because it symbolizes the return of spring and the feeling of ease during our pleasant summers here in southeast Michigan.
I love seeing the first group of robins hopping around on our yard in early spring, searching about for worms and insects. And there is nothing finer than hearing our local robins cheerily singing on a warm summer’s morning or evening.
The robin’s song is a song of summer to my ears. It sometimes is described as, “Cheerily, cheer-up, cheer-up, cheerily”. Does it sound that way to you?
But over the last few years, I’ve also been seeing and hearing more robins during our cold winters. For most of my life I thought that robins were strictly migratory birds — all of them flying south as the weather gets colder in the fall. So it’s been strange, but wonderful, seeing flocks of robins and hearing them sing and squawk during our cold gray winter days in January and February!
While most robins in my area do fly south for the winter, many will stay put as long as they can find food. And apparently more and more American Robins in my neighborhood are finding enough to eat during the winter, including the raisins and apple slices put out by our neighbors.
A Few Common Facts About the American Robin
The Most Recognizable Bird in North America
Most people in North America can identify the American Robin with its gray-brown back, darker head, and orange breast. Males have darker heads and somewhat brighter orange breasts than the female robins. Juvenile robins have speckled breasts.
Robins are in the thrush family, and are the largest of the North American thrushes, about 10 – 11 inches long (23 – 28 cm.). Since they’re so common and well-recognized, they’re often used as a size and shape reference for identifying and describing other birds.
Robins live in a wide range of habitats. You can find them in backyards, parks, marshes, fields, different types of wooded areas, and even in the tundra.
They eat worms and insects, and when those aren’t available they change their diet to berries and other fruit.
Why Do Robins Migrate?
Just as many other bird species do in North America, the American Robin migrates south to find better food sources in the winter, and migrates north in the spring to find better breeding grounds.
Robins are hardy birds that can withstand cold temperatures, but if their food source is scarce, they need to go somewhere else. If they can find enough to eat during a cold winter, they may stay put.
The American Robin can be found in most of North America, as seen from this map.
- Yellow — Summer-only range – most of Canada, northern-most United States.
- Green — Year round range – numbers vary during colder and warmer months.
- Blue — Winter-only range – southern-most United States and into Mexico.
Range map image from Wikipedia and in the public domain.
Migrating North in the Spring
Robins Move North When the Worms Come Out in the Spring
When the days start to become a little longer in the mid- and late winter, robins start to become more restless. It’s been shown that the majority of male robins start their migration north when the average temperature reaches about 36 or 37 degrees Fahrenheit. This is the time when the worms start to emerge from their winter hibernation. Since the weather conditions vary from year to year, the migration of American Robins will vary too.
As the average temperature of 36 degrees advances northward, the male robins follow. They’ll often arrive after a rain, when the worms have to move to the surface or drown — so the robins get a good meal full of protein upon their arrival!
The female robins come a little later, after the males have claimed their territories, and when the worms are plentiful and there’s mud for building nests.
Some robins migrate a short distance north while others go way up into northern Canada. They’re spread out enough so that breeding couples have a better opportunity to quickly find huge amounts of good quality, high protein food (worms), to raise their young. There’d be much more competition for food if they all stayed in the same region. When the robins are spread out, more will survive overall.
Migrating South for the Winter
Robins Flock Together in the Fall
During the late spring and earlier part of the summer, robins live in pairs in their breeding territories, and don’t mingle with other robins. In the late summer and fall, after they’re done breeding, they start to flock together in large groups, making it easier for them to find better food sources. They put on extra fat during this time in preparation for winter and their migration.
As the days get shorter, the temperatures colder, and worms and insects are harder to find, the robins start their preparations for migration. They change their diets to berries and other fruit, and if they can’t find enough food locally, they start to head south.
Robins don’t all migrate at the same time during the fall. If a flock of robins has found a good source of food, they’ll stay there until the food becomes depleted. Then they’ll move on in search of other food sources, either locally, or further south. When they find abundant food during their migration south, they’ll stay in that new area until they need to move on again to find more food.
Some migrating robins will travel for thousands of miles, from Canada to Mexico and Central America. Some don’t migrate at all, such as the individuals who live and breed in Mexico, or the few hardy robins who stay put during the cold winter months.
Robins That Over-Winter in the North
What Do Robins Eat During a Snowy Winter?
The flock of robins that I was seeing during late January in our area had probably been eating old crabapples.
When there are no worms, grubs, or insects for robins to eat, such as during the winter, they change their diet to berries and other fruit. Some berries that are very bitter in the summer and early fall become more palatable after a freeze, and are a good source of food for robins.
When one source of food is gone, they’ll go searching for another source. There certainly isn’t enough food in the colder climates to sustain the whole population of summertime, but there is enough to sustain the few hardy robins that do over-winter in the colder areas.
You can help robins out during the winter by putting out pieces of fruit such as raisins or apple slices. They’ll eat frozen fruit too. Or you can buy meal worms from a pet shop or bird food store and put them out for the robins, for a little extra winter protein.
You can also grow plants that have winter berries to feed winter robins. They will eat bittersweet, choke cherries, crabapples, bayberry, and sumac, among others.
Figuring Out Robins’ Migration Routes
Bird Banding to Collect Data
To figure out the migration patterns of robins, they are carefully captured by trained bird banders and fitted with light weight leg bands that have a unique number printed on them. Some are eventually caught again by a bird bander, and the number is entered into a data base to find where the bird was first banded. Thousands of robins are banded, and only a few are ever re-caught, so this process of collecting migration information takes a long time.
Birds are captured as they fly into “mist nets” (kind of like very large, strong hair nets), carefully removed, weighed and measured, and banded, and then released. They’re not harmed in the process! The banders record other data, including whether the robin is male or female, juvenile or adult, and other distinguishing marks that might identify the individual bird.
You may also enjoy: