Dindon sauvage

Identification

An adult male (tom or gobbler) normally weighs from 5 to 11 kg (11 to 24 lb) and measures 100–125 cm (39–49 in) in length. The adult female (hen) is typically much smaller at 2.5–5.4 kg (5.5–11.9 lb) and is 76 to 95 cm (30 to 37 in) long. Per two large studies, the average weight of adult males is 7.6 kg (17 lb) and the average weight of adult females is 4.26 kg (9.4 lb). The record-sized adult male wild turkey, according to the National Wild Turkey Federation, weighed 16.85 kg (37.1 lb), with records of tom turkeys weighing over 13.8 kg (30 lb) uncommon but not rare.<p>The wings are relatively small, as is typical of the galliform order, and the wingspan ranges from 1.25 to 1.44 m (4 ft 1 in to 4 ft 9 in). The wing chord is only 20 to 21.4 cm (7.9 to 8.4 in). The bill is also relatively small, as adults measure 2 to 3.2 cm (0.79 to 1.26 in) in culmen length. The tarsus of the wild turkey is quite long and sturdy, measuring from 9.7 to 19.1 cm (3.8 to 7.5 in). The tail is also relatively long, ranging from 24.5 to 50.5 cm (9.6 to 19.9 in).<p>Fully-grown wild turkeys have long, reddish-yellow to grayish-green legs. Each foot has three front toes, with a shorter, rear-facing toe; males have a spur behind each of their lower legs, used to spar with other males.<p>The body feathers are generally blackish and dark, sometimes gray-brown, overall, with a coppery sheen that becomes more complex in older males. Mature males have a large, featherless, reddish head and red throat, with red wattles on the throat and neck. The head has fleshy, unique growths called caruncles, which may be used to identify certain birds from one another. When toms are excited, a fleshy flap on the bill (called a snood) expands, and this, the wattles and the bare skin of the head and neck all become red with enhanced flow of blood to the head. Tail feathers are of the same length in adults but of different lengths in juveniles.<p>Males have a long, dark, fan-shaped tail and glossy, bronze wings. As with many other species of Galliformes, turkeys exhibit strong sexual dimorphism. The male is substantially larger than the female, and his feathers have areas of red, purple, green, copper, bronze, and gold iridescence. The preen gland (uropygial gland) is also larger in males compared to females. In contrast to the majority of other birds, they are colonized by bacteria of unknown function (Corynebacterium uropygiale). Males typically have at least one "beard", a tuft of coarse hair-like filaments (mesofiloplumes), growing from the center of the breast. Beards grow continuously during the turkey's lifespan and a one-year-old male has a beard up to 5 in (13 cm) long. Approximately 10% of females have a beard, usually shorter and thinner than that of the male.<p>Females have feathers that are duller overall, in shades of brown and gray. Parasites can dull the coloration of both sexes; in males, vivid coloration may serve as a signal of health. The primary wing feathers have white bars. Turkeys have approximately 5,000 to 6,000 feathers. Juvenile males are called jakes; the difference between jakes and toms is that jakes have very short "beards" and tail fans with longer feathers in the middle. The tom's tail fan feathers are uniform in length. <p>Despite usually being rather lighter than waterfowl, the turkey has the second-highest maximum average weight of any North American bird, after the trumpeter swan (Cygnus buccinator). By average mass, however, several other American birds surpass the mean weight of the turkey, including the American white pelican (Pelecanus erythrorhynchos), the tundra swan (Cygnus columbianus columbianus), the endangered California condor (Gymnogyps californianus), and whooping crane (Grus americana).

Taxonomie

Nom scientifique

Meleagris gallopavo

Autorité

Linnaeus, 1758

Ordre

Galliformes

Famille

Phasianidae

Genre

Meleagris

Répartition et habitat

Wild turkeys prefer hardwood and mixed conifer-hardwood forests with scattered openings such as pastures, fields, orchards and seasonal marshes. They seemingly can adapt to virtually any dense native plant community as long as coverage and openings are widely available. Open, mature forest with a variety of interspersion of tree species appear to be preferred. In the Northeast of North America, turkeys are most profuse in hardwood timber of oak-hickory (Quercus-Carya) and forests of red oak (Quercus rubra), beech (Fagus grandifolia), cherry (Prunus serotina) and white ash (Fraxinus americana). Best ranges for turkeys in the Coastal Plain and Piedmont sections have an interspersion of clearings, farms, and plantations with preferred habitat along principal rivers and in cypress (Taxodium distichum) and tupelo (Nyssa sylvatica) swamps.<p>In Appalachian and Cumberland plateaus, birds occupy mixed forest of oaks and pines on southern and western slopes, also hickory with diverse understories. Bald cypress and sweet gum (Liquidambar styraciflua) swamps of s. Florida; also hardwood of Cliftonia (a heath) and oak in north-central Florida. Lykes Fisheating Creek area of s. Florida has up to 51% cypress, 12% hardwood hammocks, 17% glades of short grasses with isolated live oak (Quercus virginiana); nesting in neighboring prairies. Original habitat here was mainly longleaf pine (Pinus palustris) with turkey oak (Quercus laevis) and slash pine (Pinus caribaea) "flatwoods", now mainly replaced by slash pine plantations.<p>In California, turkeys live in a wide range of habitats; acorns are a favorite food, in addition to wild oats (Avena barbata), drawing turkeys to areas of open oak forest and oak savanna across the central areas of the state. They frequent the lower-elevation oak woodlands of the Sierra Nevada foothills and Coast Ranges, and the central coast north through Mendocino County, which is primarily open conifer forest with various species of ferns growing in the understory. They can also be found in the conifer foothills and fern-heavy forested areas of the Klamath Mountains and Cascade Range in the northern areas of the state. In San Diego County, turkeys tend to be found farther from the coast, usually a minimum of 30–50 miles inland, at reasonably higher elevation; there is a healthy turkey population inhabiting the montane conifer woods and open oak forest habitats of the Cleveland National Forest, a region which borders on high desert and generally receives very minimal annual precipitation. Turkeys in these areas can be found in dense thickets of manzanita (Arctostaphylos), often growing on arid hillsides, for shelter and nesting sites, as well as rocky and boulder-strewn chaparral foothills.

Migration

Resident species

Comportement

Despite their weight, wild turkeys, unlike their domesticated counterparts, are agile, fast fliers. In ideal habitat of open woodland or wooded grasslands, they may fly beneath the canopy top and find perches. They usually fly close to the ground for no more than 400 m (a quarter mile).[citation needed]<p>Wild turkeys have very good eyesight, but their vision is very poor at night. They will generally not see a predator until it is too late. At twilight most turkeys will head for the trees and roost well off the ground: it is safer to sleep there in numbers than to risk being victim to predators who hunt by night. Because wild turkeys do not migrate, in snowier parts of the species's habitat like the Northeast, Rockies, much of Canada, and the Midwest, it is very important for this bird to learn to select large conifer trees where they can fly onto the branches and shelter from blizzards.<p>Wild turkeys have many calls: assembly call, gobble, plain yelp, purr, cluck and purr, cluck, cutt, excited yelp, fly-down cackle, tree call, kee kee run, and putt. In early spring, males older than a year old and, occasionally to a lesser extent, males younger than a year old gobble to announce their presence to females and competing males. The gobble of a wild turkey can be heard up to a mile away.[citation needed] Males also emit a low-pitched "drumming" sound, produced by the movement of air in the air sac in the chest, similar to the booming of a prairie chicken. In addition they produce a sound known as the "spit", which is a sharp expulsion of air from this air sac.[citation needed]<p>Wild turkeys are omnivorous, foraging on the ground or climbing shrubs and small trees to feed. They prefer eating acorns, nuts, and other hard mast of various trees, including hazel, chestnut, hickory, and pinyon pine as well as various seeds, berries such as juniper and bearberry, buds, leaves, fern fronds, roots, and insects. Turkeys also occasionally consume amphibians such as salamanders and small reptiles such as lizards and small snakes. Poults have been observed eating insects, berries, and seeds. Wild turkeys often feed in cow pastures, sometimes visit backyard bird feeders, and favor croplands after harvest to scavenge seeds on the ground. Turkeys are also known to eat a wide variety of grasses.<p>Turkey populations can reach large numbers in small areas because of their ability to forage for different types of food.[citation needed] Early morning and late afternoon are the desired times for eating.<p>Males are polygamous, mating with as many hens as they can. Male wild turkeys display for females by puffing out their feathers, spreading out their tails, and dragging their wings. This behavior is most commonly referred to as strutting. Their heads and necks are colored with red, white, and blue. The color can change with the turkey's mood, with a solid white head and neck being the most excited. They use gobbling, drumming/booming, and spitting as signs of social dominance, and to attract females. Courtship begins during the months of March and April, which is when turkeys are still flocked together in winter areas.<p>Males may be seen courting in groups, often with the dominant male gobbling, spreading his tail feathers (strutting), drumming/booming, and spitting. In a study, the average dominant male that courted as part of a pair of males fathered six more eggs than males that courted alone. Genetic analysis of pairs of males courting together shows that they are close relatives, with half of their genetic material being identical. The theory behind team-courtship is that the less-dominant male has a greater chance of passing along shared genetic material than if he were courting alone.<p>When mating is finished, females search for nest sites. Nests are shallow dirt depressions engulfed with woody vegetation. Hens lay a clutch of 10–14 eggs, usually one per day. The eggs are incubated for at least 28 days. The poults are precocial and nidifugous, leaving the nest in about 12–24 hours. Turkeys are a ground nesting bird, and because of this they are heavily predated on; reproductively-active wild turkeys have a lower annual survival rate due to predation of nests.

Conservation

Tendance de la population

rising