Song mimicry has always posed a bit of a puzzle to ornithologists. Almost all male birds use songs to attract females, but these musical suitors cannot succeed unless potential mates recognize their species-specific melodies. By appropriating the songs of dozens of other birds, a habitual mimic like the northern mockingbird would seem to defeat its own efforts.
As authentic as these avian impersonations may sound to the human ear however, female mockingbirds are not so easily fooled. The pitch and tempo often differ from those of the original, but even more telling is the seeming gusto with which a male mockingbird goes about his singing. Rapidly cycling through a succession of 30 or more songs, he makes it simple for a female to tell the difference.
As a male mockingbird develops a wide repertoire, he actually enhances his ability to woo a mate. Research has shown that female mockingbirds are more attracted to males with a wide selection of songs. Since it takes time for a male mockingbird to learn an array of calls, the females may simply be using their ears to find a more mature and experienced mate.
The vocal ability of mockingbirds is remarkable; one mocker whistled through the songs of 55 species in just one hour, and individual repertoires of more than 150 songs have been documented. Mockingbirds also borrow freely from the nonavian world, including barking dogs, gray treefrogs, or even a squeaky wheelbarrow.
Mockingbirds live in towns and cities, where they often forage on lawns, and in thickets, road margins, wood edges, and farms. They like a mix of low shrub and open land.
About half of the diet consists of insects and other invertebrates, and the half is native and cultivated fruits. Mockingbirds eat beetles, ants, bees, wasps, grasshoppers, and other insects. They also prey on spiders, earthworms, snails, and sowbugs.
In fall and winter, mockingbirds eat elderberries, grapes, apples, barberries, hawthorn, and their favorite rose hips. Mockingbirds compete for fruits with smaller birds, chasing other birds away from bird feeders.