Black-tailed deer or blacktail deer occupy coastal regions of western North America. There are two subspecies, the Columbian black-tailed deer (Odocoileus hemionus columbianus) which ranges from the Pacific Northwest of the United States and coastal British Columbia in Canada to Santa Barbara County in Southern California, and a second subspecies known as the Sitka deer (O. h. sitkensis) which is geographically disjunct occupying from mid-coastal British Columbia up through southeast Alaska, and southcentral Alaska (as far as Kodiak Island). The black-tailed deer subspecies are about half the size of the inland mule deer (Odocoileus hemionus hemionus) subspecies, the latter ranging further east in the western United States.

Range

The black-tailed deer lives along the Pacific coast from Santa Barbara County, California, north to southeastern Alaska. East of the Cascade Range and Sierra Nevada in Washington, Oregon and California, black-tailed deer are replaced by phenotypically different inland mule deer, the latter being much larger, with lighter pelage, more prominent rump patches and larger ears.

The black-tailed deer is currently common in California, ranging as far south as San Luis Obispo and Santa Barbara County; north into western Oregon, Washington, and coastal and interior British Columbia; and north into the Alaskan panhandle. It is a very popular game animal.

Approximately 40 deer from Oregon were released in Western Kauai, Hawaii, between 1961 and 1966. These deer thrived on the island, where they now number around 1,000. They have become a fairly popular game species on the island.

Taxonomy

All recent authorities consider black-tailed deer a subspecies of mule deer (O. hemionus). There is a large zone of admixture or hybrid swarm of black-tailed deer and inland mule deer between the east and west slopes of the Cascade Range and Sierra Nevada. This deer often is most active at dawn and dusk, and is frequently involved in collisions with automobiles.

Diet and reproduction

thumb|upright|Characteristic black tail

Deer are browsers. During the winter and early spring, they feed on Douglas fir, western red cedar, red huckleberry, salal, deer fern, and lichens growing on trees. Late spring to fall, they consume grasses, blackberries, apples, fireweed, pearly everlasting, forbs, salmonberry, salal, and maple. The mating or 'rutting' season occurs during November and early December. Bucks can be observed running back and forth across the roads in the pursuit of does. After the rut, the bucks tend to hide and rest, often nursing wounds. They suffer broken antlers, and have lost weight. They drop their antlers between January and March. Antlers on the forest floor provide a source of calcium and other nutrients to other forest inhabitants. Bucks regrow their antlers beginning in April through to August.

The gestation period for does is 6–7 months, with fawns being born in late May and into June. Twins are the rule, although young does often have only single fawns. Triplets can also occur. Fawns weigh and have no scent for the first week or so. This enables the mother to leave the fawn hidden while she goes off to browse and replenish her body after giving birth. She must also eat enough to produce enough milk to feed her fawns. Although does are excellent mothers, fawn mortality rate is 45–70%. Does are very protective of their young and humans are viewed as predators.

Deer communicate with the aid of scent and pheromones from several glands located on the lower legs. The metatarsal (outside of lower leg) produces an alarm scent, the tarsal (inside of hock) serves for mutual recognition and the interdigital (between the toes) leave a scent trail when deer travel. Deer have excellent sight and smell. Their large ears can move independently of each other and pick up any unusual sounds that may signal danger.

At dawn, dusk, and moonlit nights, deer are seen browsing on the roadside. Wooded areas with forests on both sides of the road and open, grassy areas, i.e. golf courses, attract deer. Caution when driving is prudent because often as one deer crosses, another one or two follow.

Controversy over habitat management

In Southeast Alaska, the Sitka deer is the primary prey of the rare Alexander Archipelago wolf (Canis lupus ligoni), which is endemic to the region. In the mid-1990s, the United States Fish and Wildlife Service evaluated a petition to list this wolf subspecies as threatened, and decided a listing was not warranted in August 1997, largely on the basis of provisions the Forest Service had included to protect the viability of the wolf subspecies in its Forest Plan for the Tongass National Forest, adopted three months earlier. The Tongass NF is important in wolf conservation because it includes about 80% of the region's land area. The protections for the wolf included a standard and guideline intended to retain, in the face of logging losses, enough habitat carrying capacity for deer in winter to assure the viability of the Alexander Archipelago wolf and an adequate supply of deer for hunters. The needed carrying capacity was originally specified as 13 deer per square mile, but was corrected in 2000 to 18. Use of a deer model is specified for determining carrying capacity, and is the only tool available for the purpose.

However, the Forest Service's implementation of the deer provision in the Tongass wolf standard and guideline has been controversial for many years, and led to a lawsuit by Greenpeace and Cascadia Wildlands in 2008, over four logging projects. The data set the Forest Service was using in the deer model was known through the agency's own study (done in 2000) to generally overestimate the carrying capacity for deer and underestimate the impacts of logging. Also, a conversion factor, known as the "deer multiplier" (used in calculating carrying capacity) was incorrectly applied, causing—by itself—a 30% overestimation of carrying capacity and corresponding underestimation of impacts. The combined effect of the two errors is variable because Vol-Strata is not correlated to habitat quality. Regarding the Traitors Cove Timber Sales project, in 2011 the plaintiffs noted in oral arguments before the 9th Circuit Court of Appeals that the difference is between a claimed 21 deer per square mile carrying capacity in the project EIS, and 9.5 deer per square mile (about half of the Tongass Forest Plan's requirement) according to unpublished corrections the agency made in 2008.

The 9th Circuit panel ruled unanimously on August 2, 2011, in favor of the plaintiffs, remanding the four timber sale decisions to the Forest Service and giving guidance for what is necessary during reanalysis of impacts to deer. The ruling says in part:

<blockquote>We do not think that USFS has adequately explained its decision to approve the four logging projects in the Tongass. ... USFS has failed to explain how it ended up with a table that identifies 100 deer per square mile as a maximum carrying capacity, but allows 130 deer per square mile as a potential carrying capacity. 'The agency is obligated to articulate a rational connection between the facts found and the choices made,' which the agency has not done here. Pac. Coast Fed'n of Fisherman's Ass'ns v. U.S. Bureau of Reclamation, 426 F.3d 1082, 1091 (9th Cir. 2005)... In September 2013, under the same litigation, the U.S. District Court in Anchorage made a second remand to the Forest Service because the agency's further work under the first remand had not resolved the modeling issues. Activity on the four timber sales involved in the litigation has been suspended since 2008.

References

  • Excerpts from the book Black-tailed Deer of California