The northern mockingbird (Mimus polyglottos) is a medium-sized songbird found across much of the continental United States. Though the northern mockingbird has a large range, its populations have declined in recent decades, leading some to question just how rare this iconic backyard bird has become.
Northern Mockingbird Overview
The northern mockingbird is known for its intelligence, complex vocalizations, and mimicking ability. This gray-brown bird with white wing patches and a long tail measures 8.3–10.2 in (21–26 cm) in length and weighs 1.6–2.0 oz (45–58 g). Northern mockingbirds have gray upperparts and whitish underparts. Their tails are long and display white patches when spread. A thin white wing bar is visible when their wings are extended. Northern mockingbirds have black legs and feet and a long, thin bill.
Males and females have a similar appearance. Juveniles are browner above and more heavily streaked below. The northern mockingbird’s scientific name, Mimus polyglottos, means “many-tongued mimic” in Latin. This name refers to the mockingbird’s amazing ability to mimic the sounds of other birds, animals, insect, or even artificial sounds.
Range
Northern mockingbirds breed across much of the contiguous United States, southwestern Canada, northern Mexico, the Bahamas, and the Cayman Islands. Their breeding range stretches from maritime Canada southward to Florida, the Gulf of Mexico coast, southern Texas, New Mexico, and southern Arizona. Northern mockingbirds are year-round residents across the southern portion of their range. Further north, they migrate south in winter to the southern United States and Mexico.
Habitat
Northern mockingbirds inhabit open areas with thickets, forest edges, yards, parks, and agricultural fields. They flourish in suburban and urban habitats. Northern mockingbirds require a combination of open ground for foraging and shrubs or small trees for nesting and perching.
Population and Conservation Status
The global population of the northern mockingbird is estimated at 53 million breeding birds. In the early 1900s, northern mockingbird populations exploded with the clearing of forests for agriculture and the growth of suburbs. However, in recent decades, northern mockingbird numbers have declined significantly. The North American Breeding Bird Survey reports a population decline of 1.28% per year from 1966 to 2015 in the United States and Canada. Overall, northern mockingbird populations declined by 53% during this period.
Time Period | Estimated Global Population | Population Trend |
---|---|---|
Early 1900s | Unknown (smaller than current) | Increasing |
1966 | 113 million | Near peak |
2015 | 53 million | Declining |
Multiple factors likely contribute to the northern mockingbird’s population decline, including:
- Habitat loss
- Pesticide use reducing insect food sources
- Predation by cats and other urban predators
- Collisions with buildings, towers, and vehicles
Due to its huge range and still-large population, the northern mockingbird is considered a species of Least Concern by the International Union for Conservation of Nature (IUCN). However, its declining population trends may warrant increased conservation action in the future.
Threats and Predators
The northern mockingbird faces threats from habitat loss, pesticides, predators, and collisions. Here is an overview of the major hazards impacting northern mockingbird survival:
Habitat Loss
The clearing of forests, filling of wetlands, and development of rural areas into suburbs or cities removes vital northern mockingbird habitat. They require a mix of open space and thickets or small trees. Urbanization that eliminates scrubbier areas and dense inner-city regions without greenspace reduces habitat suitability.
Pesticides
Northern mockingbirds rely on insects and fruit as major food sources. The use of pesticides and herbicides in yards, parks, and agricultural fields may limit food availability by reducing insect populations and the fruit on shrubs. Chemical exposure can also poison northern mockingbirds.
Predators
Northern mockingbirds face heavy predation from domestic cats, especially in suburban and urban areas. They frequently fall victim to collisions with buildings, towers, windows, and vehicles as they establish territories and fly about developed areas. Other predators include sharp-shinned hawks, eastern screech-owls, and snakes. As northern mockingbird populations decline, pressure from these predators grows.
Northern Mockingbird Behavior
Northern mockingbirds exhibit interesting behaviors related to their intelligence, vocalizations, territoriality, and displays:
Intelligence
The northern mockingbird is considered one of the most intelligent birds. They display observational learning and problem-solving skills. Northern mockingbirds are quick to take advantage of new food sources and have readily adapted to human environments.
Mimicry
Northern mockingbirds can mimic over 200 different species of birds, other animals, mechanical sounds, or even human songs and speech patterns. Both males and females sing and mimic sounds. They incorporate imitations into their long, complex songs used to attract mates and defend territories.
Territoriality
Northern mockingbirds are extremely territorial during the breeding season. A mated pair may defend up to 10 acres against intrusion from other mockingbirds or predators that pose a threat to eggs or young. Both the male and female participate in aggressive harassment of intruders.
Displays
Northern mockingbirds perform dramatic threat displays against intruders or predators. When provoked, they spread their wings and tails, flash their white patches, and make aggressive movements to startle or intimidate the intruder.
Northern Mockingbird Song and Calls
The song of the northern mockingbird is renowned for its complexity, volume, and mimicry ability. Here are some details on the songs, calls, and sounds of this vocal virtuoso:
Song
Male northern mockingbirds sing almost continuously throughout the spring and summer. Their songs contain a wide variety of notes, trills, whistles, and imitations of other birds blended together into long sequences. Each male has a repertoire of 50 to 200 song types that he repeats multiple times a day.
Calls
Northern mockingbirds use a variety of calls beyond their songs. Calls made throughout the year include a repeated, high-pitched note sounding like “phe-bee!” Alarm calls include harsh, buzzing notes. Begging calls from fledglings contain loud, repetitive notes.
Mimicry
Northern mockingbirds mimic sounds of over 200 other bird species including orioles, killdeer, kingfishers, and many songbirds. They can also imitate hawk screams, bird of prey warning calls, and the sounds of frogs or insects. Some mockingbirds mimic sounds like car alarms, cell phone rings, and creaky gates.
Northern Mockingbird Diet
The diet of the northern mockingbird consists mainly of insects along with fruit and berries:
Insects
Insects make up over half the northern mockingbird’s diet. They prey on beetles, grasshoppers, caterpillars, ants, wasps, spiders, and many other insects. Northern mockingbirds hunt insects on the ground or snatch them from vegetation.
Fruit
Northern mockingbirds eat the fruits and berries from a wide variety of shrubs and trees. Common fruits eaten include mulberries, wild cherries, blackberries, grapes, elderberries, and strawberries.
Seeds
Northern mockingbirds supplement their diet with various seeds from grasses, weeds, and shrubs. They swallow seeds whole, crushing them in their gizzard.
Other Foods
On occasion, northern mockingbirds may eat tree sap, nectar, acorns, small lizards, or crustaceans. They have been known to drink sugar water from hummingbird feeders.
Northern Mockingbird Reproduction
Northern mockingbirds breed between March and August depending on latitude. Here is an overview of their breeding biology:
Courtship
Males attract females by flight displays and singing. They sing continuously through the day and night during courtship. Unmated males chase females persistently while flashing their wing and tail patches.
Nests
The female mockingbird builds a nest out of twigs, grass, leaves, and bark over 2-4 weeks. Nests are cup-shaped and approximately 7 inches across. They are built 3 to 10 feet off the ground in a shrub, hedge, or small tree.
Eggs
Northern mockingbirds lay 3 to 5 eggs that are pale blue or green with red-brown spots. The female incubates the eggs for 11 to 14 days before they hatch.
Young
Both parents feed the nestlings with insects for 9 to 14 days until they fledge (leave) the nest. The fledglings cannot fly well at first and remain dependent on their parents for 2 more weeks. Northern mockingbirds may raise 2-3 broods per season.
Fun Facts About Northern Mockingbirds
- Northern mockingbirds can live up to 20 years, an impressively long lifespan for a songbird.
- They feature prominently in the lyrics of the official state songs of Florida, Arkansas, Tennessee, Texas, and Mississippi.
- The northern mockingbird is the state bird of Arkansas, Florida, Mississippi, Tennessee and Texas.
- Northern mockingbirds in southern states may not migrate at all and defend their breeding territory year-round.
- Mark Twain mentioned the northern mockingbird in writings like Adventures of Huckleberry Finn where Jim calls it a “mockin’-bird” and imitates its songs.
- Poet Emily Dickinson memorialized the northern mockingbird in her poem “Split the Lark – and you’ll find the Music.”
Conclusion
The northern mockingbird remains a common species across much of North America despite concerning population declines in recent decades. This resourceful and intelligent bird adapts readily to human environments from farmland to dense inner cities. Their complex, musical songs still ring out through spring and summer from suburban backyards to rural woodlands. With increased habitat conservation and reduced pesticide use, hopefully northern mockingbird numbers can rebound and these beloved songsters can continue serenading future generations.