There is a special family of birds that are distinguished from other bird species by their surprising vocal behavior. The melodious mimics are able to mimic sounds in their environment, including birds of different species, animals, and more!
Mimics, part of the family Mimidae, are also known as mimids. The mimics that can be seen in our area include Brown Thrashers, Gray Catbirds, and Northern Mockingbirds. These birds have complex songs and calls, used most often in territorial defense and mate attraction. Their songs consist of warbles, squeaks, and tuneful phrases, lasting up to 20 minutes.
Vocalizations of the Brown Thrasher
The Brown Thrasher (Toxostoma rufum) has one of the largest vocal repertoires of any North American songbird. Its songs are rich and full, and it is able to learn new songs. The Brown Thrasher also engages in vocal mimicry. Some birds Brown Thrashers mimic are the Northern Flicker, White-eyed Vireo, Wood Thrushes, and Northern Cardinal. They tend to repeat song units in paired phrases and may sing 1,100 different song types.
Harmonies of the Gray Catbird
Gray Catbirds (Dumetella carolinensis) sing with great vocal versatility. One reason for this is because both sides of this bird’s pharynx operate independently. They can actually sing with two voices at the same time. Gray Catbirds are often heard before being seen, distinguished by their cat-like “mew.” Songs consist of a long series of short syllables, which may be of over 100 different types delivered very rapidly. One four-and-a-half-minute Michigan catbird song was noted to include 170 distinct phrases.
Gray Catbirds mostly imitate the songs and calls of other birds and string them together. They have been heard mimicking a Brown-crested Flycatcher, probably learned while overwintering in Central America. They are believed to mimic at least 44 species of birds, frogs, can whistle and squeak, and make a variety of mechanical sounds.
Repertoire of the Northern Mockingbird
Northern Mockingbirds (Mimus polyglottos) imitate the calls and songs of other birds, including other mockingbirds. They sing almost constantly, including at night, especially during the full moon. They also mimic animal species and mechanical sounds, such as car alarms, lawn mowers, and gates opening. The Northern Mockingbird is known to mimic songs from birds it encounters in its wintering grounds. They have been heard singing the songs of the Buff-collared Nightjar and Thick-billed Kingbird in places where these species don’t even occur.
Both male and female mockingbirds sing, with the male’s repertoire often containing more than 200 songs. Male mockingbirds have two vocal repertoires, one in spring and one in fall, and they will create many new songs for the following year. They continue adding songs to their repertoire throughout their life.
Other Characteristics of Mimics
The Brown Thrashers, earthy brown on top with white stripes underneath, are short-distance partial migrants. In winter, they move out of the northern portion of their breeding range to their southern range in the eastern U.S. Southern residents remain in place year-round. They are seen at the Center from late April through early October in shrubs or foraging on the ground. They are one of our priority bird species, which means that we are working to improve their breeding habitat at the Center. Brown Thrashers eat fruit as well as insects. They are known to thrash on the ground for them or dig holes in the ground and leaf litter for prey with their longer, curved bill.
Gray Catbirds, gray with a black cap and rust-colored feathers under their tail, breed in much of the central and eastern U.S. They are neotropical migrants, flying across the Gulf of Mexico and visiting shrubby, second-growth habitats on their journey. Gray Catbirds are common at the Center, found from late April through early October, often at eye level in shrubs. They use their short, straight bill to eat fruit and a variety of insects including ants, beetles, grasshoppers, caterpillars, and moths.
A Less Common Species
Northern Mockingbirds, gray with dark wings, white wing patches, and a lighter underside, are less common in Wisconsin. They are a year-round resident throughout most of their range in North America and Mexico. The Northern Mockingbird’s diet consists of fifty percent fruit and fifty percent insects. They feed on the ground, running or hopping, and lunging at prey. The males are known for their wing-flashing display. While on the ground, they raise and lower their wings, revealing their underside to startle insects.
Mimic populations in general are in decline, partly because of development across their range and converting land for agriculture. Visit the Center this summer to hear the mew of the Gray Catbird or to listen to the intricate melodies of the Brown Thrasher.