We have a disagreement! Cornell and the Audubon website both state that the Red-winged blackbird can be found in the Decorah area year-round. But the Iowa DNR and my trusty Audubon field guide identify it as a summer resident. That particular field guide is from 1977, so their winter range may have shifted north since it was written. Red-winged blackbirds eat primarily insects during the summer, occasionally supplementing their diet with seeds. They eat seeds and grain during the winter, including corn, wheat, ragweed, cocklebur, and sunflower seeds.
A female red-winged blackbird builds her nest by winding grass and sedges around several close, upright stems. She weaves the bottom from coarse vegetation and begins filling in the nest with leaves, moss, and decayed wood before plastering it with mud and lining the inside with soft grass. Red-winged blackbirds lay two to four eggs per clutch and may produce up to two broods per year. They incubate eggs for 11-13 days and young stay in the nest for 11-14 days before fledging. To learn more, visit Cornell’s website.