Northern mockingbirds are famous for their song repertoires.
Studies have shown that males sing songs at the beginning of breeding season to attract females.
Unmated males sing songs in more directions and sing more bouts than mated males.
In addition, unmated males perform more flight displays than mated males.
The mockingbirds usually nest several times during one breeding season.
Depending on the stage of breeding and the mating status, a male mockingbird will vary his song production.
The unmated male keeps close track of this change.
He sings in one direction when he perceives a chance to lure a female from the nest of the mated male.
Unmated males are also more likely to use elevated perches to make their songs audible farther away.
Though the mockingbirds are socially monogamous, mated males have been known to sing to attract additional mates.

An observational study by Logan demonstrates that the female is continuously evaluating the quality of the male and his territory.
The assessment is usually triggered by the arrival of a new male in a neighboring territory at the beginning of a new breeding season.
In those cases, the mated female is constantly seen flying over both the original and the new male's territory, evaluating the qualities of both territories and exchanging calls with both males.
The social mate displays aggressive behaviors towards the female, while the new male shows less aggression and sings softer songs.
At the same time, both the mated male and the new male will fly over other territories to attract other females as well.
Divorce, mate switching and extra-pair matings do occur in northern mockingbirds.
Northern mockingbirds are famous for their song repertoires. Studies have shown that males sing songs at the beginning of breeding season to attract females. Unmated males sing songs in more directions and sing more bouts than mated males. In addition, unmated males perform more flight displays than mated males. The mockingbirds usually nest several times during one breeding season. Depending on the stage of breeding and the mating status, a male mockingbird will vary his song production. The unmated male keeps close track of this change. He sings in one direction when he perceives a chance to lure a female from the nest of the mated male. Unmated males are also more likely to use elevated perches to make their songs audible farther away. Though the mockingbirds are socially monogamous, mated males have been known to sing to attract additional mates.
An observational study by Logan demonstrates that the female is continuously evaluating the quality of the male and his territory. The assessment is usually triggered by the arrival of a new male in a neighboring territory at the beginning of a new breeding season. In those cases, the mated female is constantly seen flying over both the original and the new male's territory, evaluating the qualities of both territories and exchanging calls with both males. The social mate displays aggressive behaviors towards the female, while the new male shows less aggression and sings softer songs. At the same time, both the mated male and the new male will fly over other territories to attract other females as well. Divorce, mate switching and extra-pair matings do occur in northern mockingbirds.
Northern mockingbird