Red-shouldered blackbird

The red-shouldered blackbird (Agelaius assimilis), known in Cuban Spanish as mayito de la ciénaga (swamp mayito) or sargento cubano (Cuban sergeant) and turpial de hombros rojos (red-shouldered troupial), is a species of passerine bird in the family Icteridae endemic to Cuba. It is similar to other species in the genus Agelaius, but recent research has established it as a separate species from the closely related red-winged blackbird (Agelaius phoeniceus).

The males are very similar to those of the red-winged blackbird (Agelaius phoeniceus), while the females are completely black, similar to the males but without the red and yellow stripes on the wings. In addition to having a different behavior, the sexual dimorphism in size and color of the plumage of the red-shouldered blackbird is less than that of the red-winged blackbird.

It is found only in the wetlands of the island of Cuba. Although its reduced range covers only 4,100 square kilometres (1,600 sq mi), it has been classified as species of least concern. In the absence of evidence of population decline or significant threats, their numbers are believed to be stable.

The red-shouldered blackbird closely resembles the more numerous and widespread red-winged blackbird (Agelaius phoeniceus), but in contrast to phoeniceus, assimilis males and females are closer in relative size, the female is all-black instead of brown-streaked, and paired birds are monogamous. Males are about 22 centimetres (8.7 in) in length and weigh about 46 to 54 grams, while females are about 20 centimetres (7.9 in) in length and 36 to 43 grams. Like male phoeniceus, male red-shouldered blackbirds have prominent red epaulets on their wings, fringed with yellow. Immature male birds have dull epaulets, and immature females have a brownish color.