Odocoileus virginianus
(White-tailed Deer)

Description:
White-tailed deer are grayish in winter and tannish to reddish brown in summer. Their underside and throat are white. They have a larger tail than the mule deer and it is not black tipped. The tail is white underneath, which brightly shows when white-tailed deer raise their tail. Antlers on bucks consist of a single non-branching beam with single, unbranched tines or points coming off the main beam on each side. This is a distinct difference from mule deer, which have branching main beams. This species is smaller than the mule deer, males weigh between 150 and 300 pounds (63-135 kg) and females from 120 to 250 pounds (54-115 kg).

Range:
The white-tailed deer is found from southern Canada, south through most of U.S. and Mexico to South America. But, it is absent from dry, desert country and foothills though much of the southwestern United States. In Idaho and some other northern Rocky Mountain states, it seems confined primarily to river bottoms and it may be expanding its range in these states. In appears to be more common in lowland areas in northern Idaho. Because their populations have increased in recent years, they have become pests in some suburban areas of the eastern U. S.

Habitat:
This species can be found in various habitats from forests to fields with adjacent cover and especially in riparian habitat and brushy, often wet, bottomlands. In northern regions, they usually require stands of conifers for winter shelter but they avoid large stands of very dense forests. In north and in montane regions, limited ecologically by depth, duration, and quality of snow cover. In Idaho, they prefer low to intermediate elevations and dense, deciduous woodlands and brush, as well as marshy areas near water.

Diet:
In the north their diet is dominated by grasses in spring, forbs in early summer, leafy green browse in late summer, acorns and other fruits in fall, and evergreen woody browse in winter. Where winters are severe they often herd up in lowland areas with dense coniferous cover in areas called “yards”.

Ecology:
White-tailed deer are active day or night, but are mainly crepuscular . Their populations consist of two basic social groups: adult females and young; and adult and, occasionally, yearling males. Adult males are solitary during the breeding season except when attending estrus females. Their home range varies from 40 to 300 acres (16-120 ha), depending on conditions. Annual home range of sedentary populations averages 145 to 1350 acres (59-520 ha). Population density has been recorded at 1 per 6 to 47 acres (2.4-18.6 ha), depending on environmental conditions. Dispersal from the mother's home range is mostly by yearling males. Home range formation may extend over 2 to 3 years. Winter weather (snow accumulation) may strongly affect populations. Because of the dense populations in their yards, they often browse so heavily on conifer twigs and branches that they damage the plants that provide their food. Repeated use of the same yards in successive winters can reduce the ability of the vegetation to support them and malnutrition and starvation can result. Because of their “yarding” behavior in severe winters, winter weather is a more important population regulation factor than predators. This species is preyed on by canids, such as coyotes and wolves, by bears and by bobcats and mountain lions in the west. White-tailed deer vocalize with loud snorts which almost sound like a whistle at times, which serves as a danger signal. They are also famous for using their tails as a danger signal. When alerted to potential danger white-tails raise their big tails which show very white and brightly in an erected position. This serves as a clear signal of danger; it also probably helps fawns keep track of their mothers as they are feeding in dense brush or other cover. Being so numerous, especially in the eastern half of the U. S. they are probably the most popular big game animal. More than a million are shot by hunters throughout the U. S each hunting season.

Reproduction:
They breeds from late October to mid-December, the rut peaking in November. A female's receptive period lasts 1 to 2 days but, reoccurs in 3 to 4 weeks if not impregnated. Gestation varies from 187 to 222 days. Females have 1 to 2 fawns (occasionally 3 in optimal habitat ) which are born May or June. The young are reddish-brown with white spots and are initially hidden for 1 to 2 weeks. They are usually weaned by 10 weeks (by fall). Females may breed during their first fall, but usually not until their second fall (1.5 years). Males reach sexual maturity around 18 months. Few individuals exceed the age of 10 years.

Conservation:

Status:	Game species
Global Rank:	G5
State Rank:	S5

Important State References:
Pauley, G.R. 1990. Habitat use, food habits, home range, and seasonal migration of white-tailed deer in the Priest River drainage, north Idaho. M.S. Thesis, Univ. Idaho, Moscow. 153pp.