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Red-winged Blackbird Life History

Habitat

MarshesRed-winged Blackbirds spend the breeding season in wet places like fresh or saltwater marshes and rice paddies. You may also find them breeding in drier places like sedge meadows, alfalfa fields, and fallow fields. Occasionally, Red-winged Blackbirds nest in wooded areas along waterways. In fall and winter, they congregate in agricultural fields, feedlots, pastures, and grassland.Back to top

Food

InsectsRed-winged Blackbirds eat mainly insects in the summer and seeds, including corn and wheat, in the winter. Sometimes they feed by probing at the bases of aquatic plants with their slender bills, prying them open to get at insects hidden inside. In fall and winter they eat weedy seeds such as ragweed and cocklebur as well as native sunflowers and waste grains.Back to top

Nesting

Nest Placement

ShrubRed-winged Blackbirds build their nests low among vertical shoots of marsh vegetation, shrubs, or trees. Females choose the nest site with some input from the male. Typically, she puts the nest near the ground (or water surface in a marsh), in dense, grass-like vegetation such as cattails, bulrushes, sedges, and Phragmites in wetlands; goldenrod, blackberry, or willow and alder trees in uplands; and wheat, barley, alfalfa, and rice plants.

Nest Description

Females build the nests by winding stringy plant material around several close, upright stems and weaving in a platform of coarse, wet vegetation. Around and over this she adds more wet leaves and decayed wood, plastering the inside with mud to make a cup. Finally, she lines the cup with fine, dry grasses. One nest picked apart by a naturalist in the 1930s had been made by weaving together 34 strips of willow bark and 142 cattail leaves, some 2 feet long. When finished the nest is 4 to 7 inches across and 3 to 7 inches deep.

Nesting Facts

Clutch Size:2-4 eggs
Number of Broods:1-2 broods
Egg Length:0.9-1.1 in (2.2-2.7 cm)
Egg Width:0.6-0.8 in (1.6-1.9 cm)
Incubation Period:11-13 days
Nestling Period:11-14 days
Egg Description:Pale blue-green to gray with black or brown markings.
Condition at Hatching:Blind, naked with scant buffy or grayish down, poorly coordinated.
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Behavior

Ground ForagerMale Red-winged Blackbirds spend much of the breeding season sitting on a high perch over their territories and singing their hearts out. Females tend to slink through reeds and grasses collecting food or nest material. Both males and females defend nests from intruders and predators. Red-winged Blackbirds nest in loose groups in part because appropriate marshy habitat is scarce. Typically five or more (up to 15) females have to crowd their nests into any one male’s territory. They typically mate with the territory holder, though many also mate with nearby males. In fall and winter, Red-winged Blackbirds flock with other blackbirds, grackles, cowbirds, and starlings, feeding on open ground and roosting in flocks of thousands or millions of birds. Red-winged Blackbirds are strong, agile fliers.Back to top

Conservation

Low Concern

Though they may be one of the most abundant native birds on the continent, Red-winged Blackbird populations declined by about 0.72 per year throughout most of their range between 1966 and 2019, resulting in a cumulative estimated decline of 28% according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 180 million, down from 190 million in 1974. The species rates an 8 out of 20 on the Continental Concern Score, indicating a species of low conservation concern.

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Credits

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Ehrlich, P. R., D. S. Dobkin, and D. Wheye (1988). The Birder's Handbook. A Field Guide to the Natural History of North American Birds, Including All Species That Regularly Breed North of Mexico. Simon and Schuster Inc., New York, NY, USA.

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Yasukawa, Ken and William A. Searcy. (1995). Red-winged Blackbird (Agelaius phoeniceus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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