The Chalk-field is a passerine bird in the family Mimidae. Also known as Tejo-of-field, lark, arrebita-ass, cock-of-field, pope-tallow, Rufous-up-tail-robin conga or Creamy-bellied Thrush, the last name avoided by ornithologists to not cause confusion with another of the same name thrush (Turdus amaurochalinus). The Chalk-browed Mockingbird (Mimus saturninus) is a famous bird for its vast repertoire of songs, including imitations of other species.
It measures 26 cm and weighs about 73 grams. It has a gray color on the back, top of the head, wings and tail. The breast and belly are creamy white or purple for land. The white eyebrow stripe, highlighted by black stripe at eye level is an important feature for identification. The eyes of adults are yellowish, dark brown on the young birds, which also have the brindle chest dark gray. It has a long tail with white tips.
The vocalization of this species is notable for mastery with which mimics the corners and called other birds. Voice: acute and penetrating "tschrip", "tschik" (called characteristic of the species); scha-scha-scha "," krrrra "snorting (warning, anger).
There are two other species of the genus occurring in the same genre Brazil, the thrush-the-beach (Mimus gilvus), which as the name implies is restricted to the coast and can be distinguished by having the tops with gray color and the parties lower very clear, almost white. The other species is the lark-of-three-tails (Mimus triurus), which is much clearer than the Chalk-field, has white eyebrows, as well as a track on the wing, which is clearly visible when the bird is in flight, especially because the wing tip is black.
Are omnivorous, feeds mainly on invertebrates and fruit. Among the invertebrates, insects (ants, termites, beetles) are the most prey. The fruits may be wild (in the case of small size, swallowed whole) or grown such as orange and avocado. Appreciates the fruits of Tapia or Tanheiro (Alchornea glandulosa). The seeds are not digested and pass through the gut intact. The bird acts thus as a seed disperser of the fruits you eat. Most of the food is obtained as the bird moves through the soil. Other feeding methods with animal prey are less frequent, as the capture of insects in flight from high perches, or jumps from the ground. Fruits are collected by the perched bird; fruit size, grown, may have part of its pulp consumed after falling to the ground. Occasionally prey on nests with eggs and young of other birds. Makes use of fat and meat jerky blankets in the sun (hence the Pope-tallow name). Mimus saturninus foraging
The nest is built roughly with dry twigs, grass and cotton, shaped bowl raza on trees or shrubs and in certain places on the abandoned nests of other large birds. The nest center is lined with soft material. The eggs are blue-green with rust-colored spots. The female lays 3 to 4 eggs and sometimes hatching eggs of other birds. The couple is assisted by a third or fourth person in the flock, which may be years before pups that help in food and protection. Repel other birds nearby nest. The eggs hatch after 12 or 14 days and the chicks leave the nest with 11-14 days of life. The inside of the mouth of the puppies is yellow-orange.
Presents a series of behaviors, many of them poorly understood, perhaps because of the difficulty of applying a very common method of research, which is to banding. Some people who tried anilhar this bird to study its behavior gave up this feature because the bird appears to be so sensitive to the stress of capture some individuals died after banding.
Walks through the fields and closed or parks and vacant lots of cities usually in packs, which can have up to 13 members. In the southern portion of your distribution does not form flocks, and often live in couples. It has the habit of lifting the half-open wings from time to time while walking the floor, an exhibition called "wings flash", whose purpose is not understood and is also observed in other species of the genus. The flash can be performed also when the bird comes across a potential threat (too near humans, snakes).
Despite living in family groups, are very aggressive with each other and use the long beaks and strong claws on relentlessly fights (origin of cock-of-field name).
Shows the characteristic of synanthropic bird, that is, can adapt the big cities, provided they are available water and green areas where they can land, hunting and nesting.
It is one of the best imitators of other birds in nature. Some people repeat the corner up to 6 different species. In addition to these imitations, used during the breeding season (July to December), has its own corner, which makes use of the most serious and characteristic called acute, starting or ending imitation. The great Brazilian Ornithology work, Helmut Sick mentions that the populations of thrushes-the-field further south have vocalization repertoire richer and more melodious than the northernmost populations. Mimus saturninus bathing