The Northern Mockingbird (Mimus polyglottos) is famous across North America for its extensive vocal repertoire and ability to mimic sounds, including other birds and man-made noises. Singing is typically attributed to the male, who uses song to attract mates and defend territory. Although less frequently heard, female mockingbirds do sing, though their vocalizations differ in volume, complexity, and context from those of their male counterparts.
Female Vocalization
The female Northern Mockingbird’s song is less robust and significantly quieter than the male’s loud performance. Her vocalizations are often sporadic and less persistent, which is why they are less commonly noticed by humans. The female’s repertoire is generally more limited, though studies suggest they are capable of vocal mimicry, incorporating phrases from other species.
The low volume makes her song difficult to hear unless the listener is close. She tends to sing less often during the spring breeding season. When the female vocalizes, the song structure consists of repeated phrases, a characteristic style of the species.
Purpose of the Female Song
The female’s song is primarily associated with specific behavioral contexts rather than the continuous performances given by the male. One clear purpose is territorial defense, especially outside of the spring breeding season. Both sexes may sing in the fall when mockingbirds establish and defend feeding territories for the winter.
During the summer breeding season, the female rarely sings. She may occasionally vocalize when her mate is away, which may function to maintain communication within the pair or signal a temporary claim over the area. The female also uses specific calls, such as a “hew call,” often made when predators approach the nest, demonstrating her role in alarm communication.
Comparing the Sexes’ Repertoires
The most striking difference between the sexes lies in the volume and complexity of their song repertoires. The male is a celebrated vocalist, capable of learning and incorporating up to 200 distinct song types over his lifetime. His extensive song serves a primary function in sexual selection, as females often prefer males that demonstrate a larger variety of songs, signaling age and experience.
Male singing is characterized by its timing; unmated males sing frequently into the night during the breeding season. The male’s song bouts are long and continuous, used to advertise his presence and fitness and establish his domain. In contrast, the female’s singing is not typically heard at night and focuses on utilitarian, seasonal communication.
The male maintains two distinct repertoires, one for spring reproduction and another for fall resource defense. The female’s song is a less dominant feature of the species’ acoustic landscape, lacking the persistent volume and broad range of mimicry that makes the male famous.