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|In Cary, North Carolina, USA|
|Northern Mockingbird range|
Green = all year, yellow = summer only
|In Cary, North Carolina, USA|
|Northern Mockingbird range|
Green = all year, yellow = summer only
The Northern Mockingbird (Mimus polyglottos) is the only mockingbird commonly found in North America. This species was first described by Linnaeus in his Systema Naturæ in 1758 as Turdus polyglottos.
The Northern Mockingbird breeds in southeastern Canada, the United States, northern Mexico, the Bahamas, the Cayman Islands and the Greater Antilles. It is replaced further south by its closest living relative, the Tropical Mockingbird. The Socorro Mockingbird, an endangered species, is also closely related, contrary to previous opinion. The bird is the state bird of Arkansas, Florida, Mississippi, Tennessee and Texas.
This bird is mainly a permanent resident, but northern birds may move south during harsh weather. This species has occurred in Europe as an extreme rarity.
Northern Mockingbirds are medium-sized mimids that have long legs and tails, with abridged and arched wings. The Mockingbirds' color is either a gray with a grayish-brown tint for its upperparts, while its underparts have a white or whitish-gray color. It has parallel wing bars on its adjacent half of the wings conntected with its white patch that has a distinguished appearance in flight. The black central retrices and typical white lateral retrices also are noticeable in flight. The iris is usually a light green-yellow or a yellow, but has been instances of an orange color. The bill is black with a brownish black appearance at the base. The juvenile appearance is marked by its streaks on its back, distinguished spots and streaks on its chest, and a gray or grayish-green iris.
Mockingbirds measure from 20.5 to 28 cm (8.1 to 11 in) including a tail almost as long as its body. The wingspan can range from 31–38 cm (12–15 in) and body mass is from 40–58 g (1.4–2.0 oz). Males tend to be slightly larger than females. Among standard measurements, the wing chord is 10 to 12 cm (3.9 to 4.7 in), the tail is 10 to 13.4 cm (3.9 to 5.3 in), the culmen is 1.6 to 1.9 cm (0.63 to 0.75 in) and the tarsus is 2.9 to 3.4 cm (1.1 to 1.3 in).
The Mockingbird usually resides in vacated areas and forest edges. It is usually sighted in farmlands, roadsides, city parks, suburban areas, and open grassy areas with thickets and brushy deserts. When foraging for food, it prefers short grass or sheer substrate. It also has an affinity for mowed lawns. This bird refrains from residing within densely forested areas.
The Mockingbirds' breeding range is from Maritime provinces of Canada westwards to British Columbia, practically the entire Continental United States, and the majority of Mexico to eastern Oaxaca and Veracruz. The Mockingbird is generally a year-round resident of its range, but the birds that live in the northern portion of its range have been noted further south during the winter season. The bird can most frequently be found in the Southern United States. Sightings of the Mockingbird has also been recorded in Hawaii (where it was introduced), southeastern Alaska, as well as three recorded British transatlantic vagrants, though one was certain to be an escaped bird.
The Northern Mockingbird is an omnivore. The birds' diet consists of arthropods, earthworms, berries, fruits, and seeds, and seldomly, lizards. As for liquid nourishment, Mockingbirds can drink from puddles, river and lake edges, or dew and rain droplets that amass onto plants. Adult Mockingbirds also have been seen drinking sap from the cuts on recently pruned trees. Its diet heavily consists of animal prey during the breeding season, but takes a drastic shift to fruits during the fall and winter. The drive for fruits amid winter has been noted for the geographic expansion of the Mockingbird, and in particular, the fruit of the Rosa multiflora, a favorite of the birds, is a possible link.
These birds forage on the ground or in vegetation; they also fly down from a perch to capture food. While foraging, they frequently spread their wings in a peculiar two-step motion to display the white patches. There lacks consensus among ornithologists over whether this behavior is purely a territorial display, or whether the flashing white patches startles insects into giving up their cover.
Northern Mockingbird males establish a nesting territory in early February. If a female enters his territory, the male will pursue the female with initial aggressive calls and, if she becomes interested,she replies with softer calls. Once the pair is established, their song becomes more gentle. Northern Mockingbirds tend to be monogamous, and the female may return to the same male from the previous season.
Both the male and female are involved in the nest building. The male does most of the work, while the female perches on the shrub or tree where the nest is being built to watch for predators. The nest is built approximately three to ten feet above the ground. The outer part of the nest is composed of twigs, while the inner part is lined with grasses, dead leaves, moss or artificial fibers. The eggs are a light blue or greenish color and speckled with dots. Three to five eggs are laid by the female, and she incubates them for nearly two weeks. Once the eggs are hatched, both the male and female feed the chicks.
The birds aggressively defend their nest and surrounding area against other birds and animals. When a predator is persistent, mockingbirds from neighboring territories, summoned by a distinct call, may join the attack. Other birds may gather to watch as the mockingbirds harass the intruder. In addition to harassing domestic cats and dogs they consider a threat, it is not unheard of for mockingbirds to target humans. They are absolutely unafraid and will attack much larger birds, even hawks. One famous incident in Tulsa, Oklahoma involving a postal carrier resulted in the distribution of a warning letter to residents.
Young mockingbirds when first hatched rely on the adult for food for 1–2 weeks, when most of their feathers are growing at a rapid pace. Once most of the feathers have grown, the young chick will typically hop out of the nest and onto the ground. When the fledgling is able to fly, it will leave its parents and find its own food.
Mockingbirds are very social birds and young mockingbirds are sometimes seen playing with other birds. Siblings often play with each other as well. If captured when young and raised by humans, mockingbirds may also play with humans upon gaining familiarity with them. Older mockingbirds tend to stay alone for the most part. Mockingbirds sometimes "babysit" fledglings that are not their own by perching on a rooftop or a tree and watching the young bird from a distance. They will even come and have a "conversation" with the young. Not all mockingbirds are friends though, as one will sometimes steal another's catch.
Although many species of bird imitate other birds, the Northern Mockingbird is the best known in North America for doing so. It imitates not only birds but also other animals and mechanical sounds such as car alarms. As convincing as these imitations may be to humans, they often fail to fool other birds, such as the Florida Scrub-Jay.
The Northern Mockingbird's mimicry is likely to serve as a tool for increasing the size of its repertoire and thus its ability to attract females.[according to whom?] It is also possible that the bird's variety of calls serve to drive away as many competing birds, of all species, as possible. The mockingbird is limited to imitating short units of sound, which it repeats several times before moving on to a new sound. As a result, the mockingbird sounds much better (to a human ear) imitating some species than others. Species with repetitive songs, such as the Carolina Wren, are effectively copied, but species with long, complex songs, such as the Song Sparrow, cannot be effectively imitated by the mockingbird.
Northern Mockingbirds, in addition to being good mimics, are also some of the loudest and most constantly vocal of birds. They often sing through the night or when the moon is full. This is especially true of those bachelor males that are trying to attract a female. They sing year-round except sometimes for the late-summer molting season. Individual males have repertoires of 50 to 200 songs; females sing as well, but more quietly and less often than males. Mockingbirds usually sing the loudest in the twilight of the early morning when the sun is on the horizon.
In addition to its well-known song, the Northern Mockingbird uses a variety of calls to communicate specific information. As with its song, these calls are among some of the louder sounds produced by birds of its size. Mockingbirds make a harsh, raspy noise when chasing other birds out of their territory. A similar but distinct call is used when defending against predators like a hawk or falcon. Other calls include a wheezing noise, a "chuck" note, and a very piercing series of notes "high low" repeated twice.
In a paper published in 2009, researchers found that mockingbirds were able to recall an individual human who, earlier in the study, had approached and threatened the mockingbirds' nest. Researchers had one participant stand near a mockingbird nest and touch it, while others avoided the nest. Later, the mockingbirds recognized the intruder and exhibited defensive behavior, while ignoring the other individuals.
Taking shelter from the rain in a weeping holly tree
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|Wikisource has the text of the 1905 New International Encyclopedia article Mocking-bird.|