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Identificazione

Adults have a relatively short tail with the two central (deck) feathers being square-tipped and somewhat longer than their lighter, outer tail feathers giving the bird its distinctive name. The plumage is mottled dark and light browns against a white background, they are lighter on the underparts with a white belly uniformly covered in faint V-shaped markings. These markings distinguish sharp-tailed grouse from lesser and greater prairie chickens which are heavily barred on their underparts. Adult males have a yellow comb over their eyes and a violet display patch on their neck. This display patch is another distinguishing characteristic from prairie chickens as male prairie chickens have yellow or orange colored air sacs. The female is smaller than the male and can be distinguished by the regular horizontal markings across the deck feathers as opposed to the irregular markings on the males deck feathers which run parallel to the feather shaft. Females also tend to have less obvious combs.<p>Measurements:

Tassonomia

In 1750 the English naturalist George Edwards included an illustration and a description of the sharp-tailed grouse in the third volume of his A Natural History of Uncommon Birds. He used the English name "The Long-tailed Grous from Hudson's-Bay". Edwards based his hand-coloured etching on a preserved specimen that had been brought to London from Hudson Bay by James Isham. When in 1758 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the tenth edition, he placed the sharp-tailed grouse with other grouse in the genus Tetrao. Linnaeus included a brief description, coined the binomial name Tetrao phasianellus and cited Edwards' work. The sharp-tailed grouse is now placed in the genus Tympanuchus that was introduced in 1841 by the German zoologist Constantin Wilhelm Lambert Gloger for the greater prairie chicken. The genus name combines the Ancient Greek tumpanon meaning "kettle-drum" with ēkheō meaning "to sound". The specific epithet phasianellus is a diminutive of the Latin phasianus meaning "pheasant".<p>The greater prairie chicken, lesser prairie chicken, and sharp-tailed grouse make up the genus Tympanuchus, a genus of grouse found only in North America. Six extant and one extinct subspecies of sharp-tailed grouse are recognised:

Nome scientifico

Tympanuchus phasianellus

Autorità

(Linnaeus, 1758)

Ordine

Galliformi

Famiglia

Phasianidae

Genere

Tympanuchus

Areale e habitat

Sharp-tailed grouse historically occupied eight Canadian provinces and 21 U.S. states pre-European settlement. They ranged from as far north as Alaska, south to California and New Mexico, and east to Quebec, Canada. Following European settlement the sharp-tailed grouse has been extirpated from California, Kansas, Illinois, Iowa, Nevada, and New Mexico.

Migrazione

Resident species

Comportamento

These birds forage on the ground in summer, in trees in winter. They eat seeds, buds, berries, forbs, and leaves, also insects, especially grasshoppers, in summer. Specific species of grasshopper the sharp-tailed grouse is known to feed on are Melanoplus dawsoni and Pseudochorthippus curtipennis.<p>The sharp-tailed grouse is a lekking bird species. These birds display in open areas known as leks with other males, anywhere from a single male to upwards of 20 will occupy one lek (averaging 8-12). A lek is an assembly area where animals carry on display and courtship behavior. During the spring, male sharp-tailed grouse attend these leks from March through July with peak attendance in late April, early May. These dates do fluctuate from year to year based on the weather. Johnsgard (2002) observed weather delayed lekking of up to two weeks by sharp-tailed grouse in North Dakota. The males display on the lek by stamping their feet rapidly, about 20 times per second, and rattle their tail feathers while turning in circles or dancing forward. Purple neck sacs are inflated and deflated during display. The males use "cooing" calls also to attract and compete for females. The females select the most dominant one or two males in the center of the lek, copulate, and then leave to nest and raise the young in solitary from the male. Occasionally a low-ranking male may act like a female, approach the dominant male and fight him.

Conservazione

These birds are increasing in numbers and are listed as least concern.

Tendenza della popolazione

rising