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| Washington
Wildlife Areas
Sharp-tailed Grouse Biology and Management |
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Sharp-tailed Grouse Biology and Management The information presented here has been reprinted from the Sharp-tailed Grouse Programmatic Management Plan. Columbia River Wildlife Mitigation Grand Coulee Dam Project. Mike Kuttel and Paul Ashley, Washington Department of Wildlife. 1992. Distribution/Current Status/Limiting Factors Sharp-tailed grouse populations have declined considerably in Washington State since the turn of the century. The primary factors responsible for the decline of these species are the conversion of native shrub-steppe habitat for agricultural purposes, construction of hydropower facilities, fragmentation of existing habitats, overgrazing, and tree removal from riparian areas (Yokum, 1952; Ziegler, 1979). Conversion of native shrub-steppe/grasslands to crops, coupled with heavy livestock grazing and fragmentation of the remaining rangelands, has significantly reduced the amount and quality of shrub-steppe habitat throughout Eastern Washington. As a result, shrub-steppe dependent wildlife species such as sharp-tailed grouse currently occupy only a fraction of their former range.
The sharp-tailed grouse originally occupied prairie habitats in nearly every county in eastern Washington. However, by the early 1950s their range had been reduced to scattered populations in unfarmable scablands (Yokum, 1952). In 1979 Ziegler reported that sharp-tailed grouse range had been further reduced to central Okanogan, north Douglas, and central Lincoln counties. Sharp-tailed grouse are also found on the Colville Indian Reservation where their status is currently declining. Sharp-tailed grouse are now a State threatened species and Federal candidate species for classification as threatened or endangered status. The Federal classification has been petitioned twice, but lacked support due to viable populations in other states. Therefore, it is important to provide timely protection and enhancement for this species to avoid federal classification under the Endangered Species Act and improve overall population health within Washington State.
Areas that continue to support the most viable populations, based on breeding ground attendance, include the area around West Foster Creek, East Foster Creek, and Dyer hill in Douglas County; the area around Tracy Rock and Swanson Lake in Lincoln County; and the Scotch Creek/Johnson Creek/Happy Hill area, the Tunk Valley, and near the town of Chesaw in Okanogan County. In addition to habitat conversion for agricultural purposes, another limiting factor that has been identified by other states is fire control. Wildfires maintained grasslands and brush habitat that sharp-tails require rather than allowing coniferous trees to dominate the landscape (Kessler and Bosch, 1981; Hamerstrom et al., 1951). This is a possible factor in Washington where sharp-tailed grouse habitats occur in transition zones between sage brush/grasslands and forested types. Life History The Columbian sharp-tailed grouse subspecies begin to congregate around their breeding grounds, known as leks, as soon as the snow recedes in March. Males establish territories on the leks that are defended from other males. Typically, the central portion of the lek site is where the older, more aggressive grouse select territories. These older birds usually do most of he breeding (Johnsgard, 1973). The females begin to arrive on the breeding grounds shortly after the males. Peak attendance in Washington occurs in the middle to latter part of April. The males perform a display ritual often described as a dance. The purpose of the ritual is to attract a female for breeding. Once bred, the female leaves the lek and continues the nesting process (Johnsgard, 1973). The hen will lay about one egg per day until she completes a clutch of 12 eggs. The incubation period averages 23 days. Additional nests will be attempted if the initial nest is destroyed (Glesen, 1987; Johnsgard, 1973). Nest success is usually greater than 50 percent, and five to six young survive per brood. Once the chicks are ten to 12 weeks old, they become fairly independent and the broods often disperse. By fall, sharp-tails can often be found back near the lek with males beginning to establish territories. As winter arrives, large flocks are formed and the birds move to available food sources (Johnsgard, 1973).
Habitat Requirements In Washington sharp-tailed grouse inhabit sagebrush-grasslands or mountain shrub habitats. Important vegetation includes bunchgrass, sagebrush, snowberry, serviceberry, and water birch (Glesen, 1987; Ziegler, 1979; Artmann, 1970). Leks or dancing grounds are typically located on a knoll in rolling terrain or a flat spot in channeled scablands. The vegetation at the lek site will usually be sparse (Ziegler, 1979; Johnsgard, 1973; Sisson, 1971; Jones, 1966). These characteristics allow for a conspicuous display area for birds to gather and breed (Johnsgard, 1973). The lek is the focal point for a local population of sharp-tailed grouse and most other annual activities are conducted within two or three miles of the lek. The annual home range can be much smaller when all of the habitat needs of the birds are met in a small area. Sharp-tails usually select vast areas of tall, dense grass within a few miles of the lek for nesting. Most nests are located under the cover of the previous year’s growth of grass or concealed under shrubs (Kohn, 1976). Hoffmann and Dobler (1988) noted that sharp-tails typically selected north slopes for nesting. These slopes usually consist of taller, denser vegetation because of better soil moisture that results from the shaded aspect. Brooding cover contains higher percentages of brush and broadleaf plants than nesting cover (Klott and Lindzey, 1990). In addition to foraging on large amounts of broadleaf plants, young chicks eat a significant amount of insects. High insect densities occur in areas with large numbers of broadleaf plants. As the summer progresses, sharp-tails tend to move to riparian areas or mountain shrub communities to search for green succulent vegetation, ripening berries, and shade. Winter habitats also include mountain shrub communities and riparian areas where berries, seeds, and buds can be found for food. A variety of habitats are used until snow forces the birds into taller vegetation. Sharp-tails will burrow in to snow to roost and escape from harsh weather; however, crusted snow conditions cause them to roost in trees and shrubs.
Habitat Management Conversion of shrub-steppe/grassland habitat to agricultural crops, coupled with intensive livestock grazing and the degradation of riparian areas, have resulted in sharp-tailed grouse population declines in recent years. Land management practices aimed at enhancing conditions for prairie grouse must address those three factors. Management of Agricultural Areas The conversion of land from native habitats to agriculture should be curtailed in areas specifically managed for sharp-tails. In addition, native vegetation should be reestablished on croplands included within mitigation efforts. This could be done by compensating private landowners, enrolled or extending contracts in the USDA’s CRP, or purchase via perpetual easements or fee title. The revegetation of croplands should include seeding with a high percent (40% - 50%) of forbs and a combination of perennial grasses listed previously. A variety of grasses, forbs, and shrubs are needed by sharp-tails to satisfy habitat needs throughout the year. Annual grasses and noxious weeds such as cheatgrass and knapweed may be detrimental to grouse because they compete with more important vegetation. Weed control measures and vegetation management should focus on reducing the dominance of these weeds in the landscape. Management of Grazing Areas Several authors have documented the degradation of habitat that accompanies livestock grazing. Some recommend the use of fire rather than grazing to maintain vigorous stands of grasses and forbs. Light grazing can be used to manage vegetation, but must often be combined with other techniques. Most of the shrub-steppe habitat in Washington has been intensively grazed since the late 1800s. Habitat that is managed for the sharp-tailed grouse may initially require a no-grazing regimen in order to allow the vegetation to recover sufficiently for sharp-tailed grouse use. In some areas range seedings may also be needed to improve the ecological condition of rangelands that have been severely overgrazed by livestock. Grazing could be resumed once the vegetation has recovered enough to meet the needs of the grouse. Most studies indicate that a rest-rotation grazing system provides the most benefits to sharp-tails. Pastures managed for grouse should be rested more often than they are grazed or, at most, grazed in alternating years. Grazing will only be used when found to be consistent with the biological needs of the grouse. Tall, dense, residual grass cover is important to nesting grouse. Sharp-tails avoid areas that have been heavily grazed or that are being grazed before and during nesting season. Residual grasses should be at least 12 inches tall and uniform over large areas. Several authors used visual obstruction readings (VOR) to determine habitat selection for nesting. Robel, et al. developed the most commonly use VOR technique. An average minimum VOR of two (or pre-green-up value of one) results in high nest site selection and increased nesting success. Ground cover provides nesting habitat, provides cover from harsh weather and protects birds from predators. A VOR of greater than three is best for brooding grouse. This value is likely influenced by the selection of mountain shrub and mesic sites. A high forb (>20 percent) component is also important for providing high quality brooding habitat. Management of Riparian Areas Brush, shrubs, and trees that grow along streams and draws provide critical winter food for sharp-tails. Woodcutting, land clearing, herbicide drift, and livestock grazing have resulted in the loss of important winter habitat. In order to enhance an area for sharp-tails, existing winter food sources should be protected and new ones developed. Water birch, aspen, chokecherry, and serviceberry are the most important components. Two-acre clumps of winter habitat should be established at short intervals along streams, draws, and at springs. General Management Dancing grounds should not be disturbed to prevent abandonment by breeding grouse. Site visitations, construction, farm equipment, and grazing should be restricted from the area near leks from April through June. Insecticides have caused death and behavior modification in adult grouse and have resulted in lower chick survival by reduced food availability. Herbicides cause similar problems of reduced food availability, which results in lower chick survival, and avoidance of the site by adults. The use of pesticides should be avoided or at least greatly restricted. Chemical control of pests should be the last resort. Literature cited:
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