It breeds from Alaska and Newfoundland south to Florida, the Gulf of Mexico, Mexico, and Guatemala, with isolated populations in western El Salvador, northwestern Honduras, and northwestern Costa Rica. It may winter as far north as Pennsylvania and British Columbia, but northern populations are generally migratory, moving south to Mexico and the southern United States. Claims have been made that it is the most abundant and most well studied bird in North America. The Red-winged Blackbird is sexually dimorphic; the male is all black with a red shoulder and yellow wing bar, while the female is a nondescript dark brown. Seeds and insects make up the bulk of the Red-winged Blackbird's diet.
Marshes and fields.
Red-winged Blackbirds are one of our most abundant birds. They are here throughout the year and in winter large flocks are quite common. They may be found in almost any habitat. Females and juveniles do not look at all like adult males. They are streaky brown with prominent eyebrows, looking more like overgrown sparrows. The song is distinctive and once recognized, easy to identify. Kenn Kaufman describes it as aawnk-ah-rrreeeeee.