The term blackbird loosely refers to a diverse group of about 10 species of North American birds that belong to the subfamily Icterinae.
In addition to blackbirds, this subfamily includes orioles, meadowlarks, and bobolinks.
The various species of blackbirds have several traits in common.
The males are predominantly black or iridescent in color.
All blackbirds have an omnivorous diet consisting primarily of grains, weed seeds, fruits, and insects.
The relative proportions of these food groups, however, vary considerably among species.
Outside of the nesting season, blackbirds generally feed in flocks and roost at night in congregations varying from a few birds to over one million birds.
These flocks and roosting congregations are sometimes comprised of a single species, but often several species mix together.
Sometimes they are joined by non-blackbird species, notably European starlings (Sturnus vulgaris) and American robins (Turdus migratorius).