They consume seeds of grasses and weeds, and grains dropped by farm machinery. Flocks of red-winged blackbirds may damage corn, wheat, oats, barley, rice and sunflower crops. Adults usually breed within 30 miles of where they were hatched. In spring the males perch prominently, displaying their epaulets and calling to attract females and intimidate other males. A male may mate with several females, and a female may mate with more than one male.
Females first breed when they're one year old.
Redwings nest in loose colonies. They aggressively attack crows and hawks to drive them out of the area. Males do not help with nest building. A female lays three or four pale bluish eggs, blotched with browns and purples. Incubation takes 10 days to two weeks.