In size the yellow-shouldered blackbird is slightly smaller than the red-winged blackbird. Adults and juveniles of both sexes have all black plumage with yellow epaulettes. Juveniles can be distinguished from adults by black speckling over the edges of the epaulettes. Adult males are significantly larger, about 17 percent by weight, than the females. Although this species is omniverous, it can be basically characterized as an arboreal insectivore. During the nesting season the young's diet is about 9O percent arthropod material. At bird feeders and around domestic animals, this blackbird has been observed to take cattle ration, dog food, monkey chow, nectar, fruit, cooked rice, and granulated sugar.