Tuesday, April 24, 2007

Northern Mockingbird

The Northern Mockingbird, Mimus polyglottos, is the mockingbird commonly originate in North America.Adults are grey on the head and upperparts with pale yellow eyes and a slim black bill with a slight downward curve; the underparts are light. They have a long dark tail by means of white edges and long dark legs. They have white wing bars and show white wing patches in flight.Their breeding habitat is areas with a mix of open areas and dense shrubs from southern Canada to Mexico, but is most common in the southern United States. They build a twig nest in a dense shrub or tree. This bird forcefully defends its nest against other birds and animals, including humans. When a predator is persistent mockingbirds from adjacent territories, summoned by a distinct call, may join the attack. Other birds may gather to watch as the mockingbirds harass the intruder.
They are usually permanent residents; northern birds may move south during harsh weather. However, this species has occurred in Europe as an extreme rarity.These birds forage on the ground or in vegetation; they also fly down from a perch to capture food. They mainly eat insects and berries. While foraging they will regularly spread their wings in a peculiar two-step motion to display the white patches underneath. The purpose of this behavior is disputed. Some ornithologists claim this is merely a territorial display, while others say that flashing the white patches startles hiding insects and forces them into the open. Both theories seem to have some merit.
This bird imitates the calls of other birds, animal sounds and yet machine noises. It is often found in urban areas. They often call through the night and may continue year-round apart from for the summer moulting season. Mockingbirds usually sing the loudest in the twilight of the early morning when the sun is on the horizon. While singing on a high perch they will often bolt more than a few feet into the air in a looping motion, with wings outstretched to display their white underside, then land back on the perch without breaking a note. That serves as a territorial display.Mockingbirds have a strong preference for certain trees, such as maple, sweet gum (green 5-pointed leaves and prickly porous balls), and sycamore. They normally avoid pine trees. In urban areas, mockingbirds rarely come down to the ground, unlike most birds. Also, they have a particular preference for high places, such as the topmost branches of trees and the tops of telephone poles.

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