These female hummingbirds evolved to look like males — apparently to evade aggression
University of Washington1 in 5 adult female white-necked jacobin hummingbirds look like males. New research from the University of Washington shows that this is a rare case of "deceptive mimicry" within a species: Females with male-like plumage are trying to pass themselves off as males, and receive a benefit in the form of reduced aggression.