American Robins are a familiar sight across Michigan, often seen hopping on lawns in search of food. Their presence throughout the year can lead to questions about their movements, as many birds undertake seasonal journeys. This common backyard bird, known for its reddish-orange breast, exhibits complex migratory behaviors.
The Migratory Nature of Michigan Robins
The American Robin is classified as a short-distance migrant, meaning many individuals do not travel thousands of miles for winter. While some populations, particularly those breeding further north in Canada, embark on longer journeys, Michigan’s robins typically move shorter distances. Most robins that breed in Michigan do migrate, but not all of them leave the state entirely.
Timing and Triggers of Migration
American Robins begin their southward migration from Michigan in the fall, peaking through October and November. This movement is driven by decreasing availability of their preferred food sources, as temperatures drop and the ground freezes, making earthworms, beetle grubs, and other soft-bodied invertebrates largely inaccessible. While robins can switch their diet to berries in winter, the dwindling supply of ground-dwelling insects prompts migration. In spring, their northward return is influenced by the 37-degree Fahrenheit isotherm, allowing the ground to thaw. Male robins arrive at breeding grounds before females, securing territories.
Wintering Grounds and Year-Round Residents
Michigan robins that migrate generally move south to areas where food remains abundant, including southern Canada, most of the United States, and central Mexico. Their wintering range is broad and can vary year to year depending on local food supplies. Not all robins depart from Michigan; a portion of the population remains in the state throughout the winter months.
These year-round residents adapt to the colder conditions by altering their diet and behavior. They shift from a summer diet rich in invertebrates to one focused on fruits and berries, including junipers, hollies, crabapples, and hawthorns. Access to reliable food sources and dense coniferous trees enables them to withstand the cold.
During winter, robins become nomadic, forming large flocks that can number in the hundreds or even thousands, a contrast to their territorial behavior in warmer months. This communal roosting helps them locate food and provides protection from predators. Male robins may be more inclined to stay in northern areas, gaining an early advantage in claiming prime breeding territories when spring arrives.