The male blue grosbeak is almost entirely deep blue. The female is mostly brown. Both sexes are distinguished by their large, deep bill and double wing bars. These features, as well as the grosbeak’s relatively larger size, distinguish this species from the indigo bunting.
This is a migratory bird, with nesting grounds across most of the southern half of the United States and much of northern Mexico, migrating south to Central America and in very small numbers to northern South America; the southernmost record comes from eastern Ecuador. It eats mostly insects, but it will also eat snails, spiders, seeds, grains, and wild fruits. The blue grosbeak forages on the ground and in shrubs and trees.