Red-winged blackbirds weigh as much as 85.0 grams. They are approximately 24.0 centimeters long, and can have a wingspan of 37.0 centimeters. Red-winged blackbird males and females are different in size and coloration. The male is black overall with red "shoulders" edged with white, pink, or yellow feathers. Males are also slightly larger than females. The female is brownish overall and lacks any red color.
During the breeding season, the prefered habitat is marsh. Red-winged blackbirds are found in cattail, tule, sedge, and salt marshes as well as in wetlands. They are also found in wet shrubby fields, at the edge of secondary growth, hayfields, old fields, pastures, and even urban parks. During the winter, red-winged blackbirds are found in open fields and croplands.
Male red-winged blackbirds defend territories in which as many as 15 females establish nesting areas. Most male territories contain about 5 females. Females mate mostly with the male in whose territory they live, but will also mate with other males.
Males attract females for mating by having large and attractive territories with plentiful resources. They also use vocalizations and postures to attract a female for mating.
Nest building begins between March and May. Usually, the further south you go, the earlier the nest is built. Males select the nesting site and actively defend it. After a female accepts the male and his site, the nest is built in or near marshland or moist, grassy areas. Plant materials, such as cattail stalks, are woven together to form a basket above water level, and soft materials are used to line the nest. Three to five pale greenish-blue, black or purple streaked eggs are laid per clutch. Each egg is approximately 2.5 by 1.8 cm. Females will incubate the eggs (sit on the nest and keep the eggs warm until they hatch) while the male guards the nest. The female incubates the eggs for 11 to 13 days. Chicks fledge (are able to fly) in 10 to 14 days and are independent in 2 to 3 weeks. Juveniles usually reach adulthood in 2 to 3 years.
When the eggs hatch, the young are blind, uncoordinated, and dependent on care from adults. Females are generally responsible for feeding and caring for the young. However, at times, the male will help with the first clutch and later in the breeding season.
In the wild, red-winged blackbirds live 2.14 years, on average. The olded recorded red-winged blackbird in the wild lived 15 years and 9 months.
These birds are some of the first springtime birds to return from their wintering sites. Once males arrive, they devote their time to defending their territory. The most successful defenders are not necessarily the most aggressive birds. Males that spend more time in, as well as foraging on, their territory are more likely to retain ownership of that territory.
Males with darker colored shoulders do not tend to keep their territories. Typically in the spring, male red-winged blackbirds display in a "song spread." They fluff their plumage, raise their shoulders, and spread their tail as they sing. As the display becomes more intense, the wings are more arched with the shoulders showing more prominently. Males use this same body display as a threat to other male birds that enter into the male's territory.
Females will also engage in a "song spread" display directed at each other early in the breeding season. One possibility is that a female will defend a sub-territory within the male's territory. The female will engage in a "wing flip" display when a disturbance prevents her from returning to her nest full of young.
Red-winged blackbirds are active during the day and migrate between their summer breeding grounds and winter feeding areas. During the winter, red-winged blackbirds aggregate in huge flocks and tend to stay in or near areas where grains and seeds are available to eat.
Home range and territory size vary greatly among red-winged blackbirds given their broad geographic range and extensive use of varying habits. Males tend to control territories of approximately 2,000 square meters. Females will occupy the territory of a single male, along with many other females. Birds in Costa Rica defend territories that are two to four times the size of temperate birds to the north.
Red-winged blackbirds communicate vocally and visually. In the eastern United States, male red-winged blackbirds utter their familiar song of "oak-a-lee" or "konkeree" in the spring. The last syllable is given more emphasis as a scratchy or buzzy trill. The common call used by both males and females is a "check" call. Males may utter a whistled "cheer" or "peet" call if alarmed. Other calls made by the male include a "seet," a "chuck," or a "cut." Females may utter a short chatter or sharp scream. A pre-mating call, "ti-ti-ti," may be uttered by both sexes.
During the breeding season, red-winged blackbirds eat mostly insects, spiders, and other invertebrates. At other times of the year, they diet on weed seeds, crop grains, as well as invertebrates. They have been known to forage (search for food) in rice fields and other croplands. They have been known to also eat a wide variety of other foods as they are available, including carrion, worms, snails, fledgling birds, eggs, and frogs.
Red-winged blackbirds are aggressive birds, even attacking humans that accidentally wander into their nesting territories. Groups of red-winged blackbirds can drive away much larger predators by ganging up on them. Red-winged blackbirds are probably preyed upon by a diverse set of predators, including raccoons, weasels, snakes, foxes, skunks, and raptors. Most predation occurs on babies in the nest (called nestlings) and eggs. Red-winged blackbirds also avoid predation on their eggs and fledglings by making their nests over water, in dense foliage, and 1 to 2 meters above the ground. Females are brownish and drab in coloration, making them difficult to see when they are on their nest.
Red-winged blackbirds are important predators on invertebrates in their breeding grounds and can have a large impact on grain and seed availability in their winter flocks.
Another species of bird, the brown-headed cowbird, uses red-winged blackbirds as a host to raise their young. Brown-headed cowbirds are nest parasites on red-winged blackbirds. These cowbirds will puncture one of the blackbird's eggs and lay their own egg in the nest. The cowbird egg is then hatched and taken care of along side the red-winged blackbird nestlings.
Red-winged blackbirds may act as crop pests during winter when they aggregate in large numbers.
Red-winged blackbirds consume insects, which provides pest control.
Red-winged blackbirds are widespread and abundant, as migratory birds they are protected under the U.S. Migratory Bird Act.
This bird has a body temperature of 38.2 to 40.3 degrees Celcius.
This bird is also commonly known as the "Redwing".
There are 26 subspecies.