Males are typically the most vocal. They sing to establish and defend their territory and to attract a mate.

Females of some species such as the Northern Cardinal will also sing.

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Female cardinal. Photograph © Greg Lavaty

Northern Cardinal females will sing from the nest, despite the risk of giving away the nest location. One theory is the song may give the male information about when to bring food.

Mated cardinals share song phrases, but the female may actually outdo the male in some ways, singing a longer and more complex song than the male.