The Red-winged Blackbird is one of North America’s most abundant and recognizable avian species. This bird is a highly adaptable and opportunistic omnivore, thriving in diverse environments across the continent. Its flexible diet allows it to exploit resources in habitats ranging from dense freshwater marshes to open agricultural fields. The feeding habits of this species are governed by the availability of energy sources throughout the year.
Invertebrates and Protein Sources
The blackbird’s diet consists primarily of various invertebrates, which are especially sought after during the breeding season. This animal matter is essential for fueling the energetic demands of nesting and supplying the nutritional needs of rapidly developing young. The birds consume an array of terrestrial insects, including caterpillars, grasshoppers, and beetles such as weevils and rootworm beetles.
They also target aquatic life, which they access in the marshy habitats where they often reside. This includes dragonfly and damselfly nymphs, along with snails and other mollusks. Spiders and other arthropods are also regularly consumed. The concentrated protein and fat from these sources are necessary for migration preparation and for the rigorous activity of establishing territories and raising multiple broods.
Plant Matter and Seed Consumption
The blackbird’s omnivorous diet consists of plant matter, particularly seeds and grains. They consume a wide variety of seeds from common weeds, including species like ragweed, smartweed, and cocklebur. The birds will also forage heavily on the waste grain that remains in fields following a harvest.
This often includes common agricultural products like corn, rice, oats, and wheat. In agricultural areas, the blackbirds are known to feed on ripening crops such as corn, especially when the grain is in its soft “milk” stage. This feeding on cultivated grains, along with sunflower seeds, often leads to the species being considered a pest in farming communities. Less frequently, they will supplement their diet with soft fruits and berries, such as blueberries and blackberries, when they are seasonally available.
Seasonal Dietary Changes and Foraging
The ratio of animal matter to plant matter in the blackbird’s diet shifts based on biological need and resource availability. During the late spring and summer nesting period, the diet becomes highly insectivorous, with invertebrates sometimes making up 75 to 90% of the food consumed. This focus on protein supports the growth of nestlings and the high energy output of parental care.
As summer ends and temperatures fall, the diet transitions to a high-carbohydrate intake, becoming 75% or more comprised of seeds and grains for maintenance and migration. Foraging behavior adapts to these seasonal changes; during the breeding season, they probe the mud and bases of aquatic plants with their bills to find hidden insects. In the non-breeding season, they form massive flocks to glean waste seeds and grain from open agricultural fields, often traveling long distances daily from communal roosts to foraging grounds.