Breeding and Nesting - Site and Requirements
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. When finished the nest is 4 to 7 inches across and 3 to 7 inches deep.
Nest Placement:
Red-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.
(female Red-winged Blackbird)