As most young male birds get ready to leave the nest, they learn their species’ song by hearing their male parent sing it again and again. They imprint on their father’s song. So how does a Brown-headed Cowbird, raised by parents of a different species, learn to sing the correct song? The “chatter call” of an adult cowbird triggers something in the young bird’s brain. Like a kind of “password,” the chatter call guides the young bird in recognizing what species to identify with, even though cowbirds are fostered by as many as 220 different species!More info and transcript at BirdNote.org. Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.