Carolina Wren singing his heart out. Unlike other wren species, only the male Carolina Wren sings the loud song. In other species, such as the Stripe-breasted Wren of Central America, both members of a pair sing together. The male and female sing different parts, and usually interweave their songs so that they sound like a single bird singing. | Jen Marie Photography

Carolina Wren Identification, All About Birds, Cornell Lab of Ornithology