The Black Jacobin is a striking black and white endemic of woodland habitats from eastern Brazil south to northeast Argentina in a fairly narrow band along the coast. The Black Jacobin appears to have converted all green or violet plumage on its sister species to black, making it quite conspicuous in flight. It feeds on the nectar of various native and introduced shrubs and trees and will occasionally occur in congregations of 50 or more individuals around particularly rich nectar resources. Feeds also on insects in the air, or gleans from leaves and spider webs, and sometimes has been recorded feeding in association with mixed-species flocks of other birds. It is one of the most territorial and dominant hummingbirds within its range, competing both with conspecifics and individuals of other species at food resources. It is a migratory bird, however, phenology of migration pattern poorly understood.
