Important Bird Areas

Commissary Ridge Raptor Migration Route

Wyoming

The site includes public lands east of the Utah border, south of 42?? 30??, north of 41??30?? and west of 110?? 26??. The outstanding landform features are the north/south running formations including: Commissary Ridge, Rock Creek Ridge, Dempsey Ridge, Sillem Ridge, Boulder Ridge, Absoroka Ridge, Tunp Range, Sublette Range, and the Bear River Divide. The habitat consists of sage-steppe, desert sage, grassland range, badlands, dunes, mountain shrub communities, aspen stands, conifer forest, lakes, intermittent streams, and cliffs.

Ornithological Summary

The area is one of three known raptor fall migration corridors in Wyoming, as determined by HawkWatch International in the fall of 2001. Some areas within the Commissary Ridge area are easily assessable and therefore logistically, can support the establishment of a long-term raptor-monitoring project, which includes surveys and raptor banding. Easy access to the area also provides opportunities for public education about the importance of the area for raptor migration. Endangered, threatened, and special concern species ? According to the USFWS, the Kemmerer Resource Area has are two bird species listed under the Endangered Species Act. The Bald Eagle is threatened, and the Yellow-billed Cuckoo is a candidate species. ? The species of special concern in the area according to the IBA criteria handout are: Mountain Plover, Northern Goshawk, Merlin, Long-billed Curlew, Ferruginous Hawk, Burrowing Owl, Peregrine Falcon. ? The Wyoming BLM Sensitive Species list contains many bird species that can be found in the Commissary Ridge IBA area: Northern Goshawk, Ferruginous Hawk, Peregrine Falcon, Greater Sage-grouse, Long-billed Curlew, Yellow-billed Cuckoo, Burrowing Owl, Sage Thrasher, Loggerhead Shrike, Brewer?s Sparrow, Sage Sparrow, Baird?s Sparrow, and Mountain Plover. #2 ? Other high conservation priority species ? Partner?s in flight ?High Conservation Priority? birds located in the area are: Vesper Sparrow, Sage Sparrow, Brewer?s Sparrow, Sage Thrasher, Western Bluebird, Townsend?s Warbler, Loggerhead Shrike, Calliope Hummingbird, Broad-tailed Hummingbird, Sage Grouse, American Dipper, Short-eared Owl. Western Screech-owl, Three-toed Woodpecker, Cordileran Flycatcher, Willow Flycatcher, Brown Creeper, Red-naped Sapsucker, Williamson?s Sapsucker, Golden-crowned Kinglet, Dusky Flycatcher, Hammond?s Flycatcher, Swainson?s Hawk, Wilson?s Phalerope, MacGillivray?s Warbler, Lark Bunting, Gray?s Flycatcher. #4 ? Significant concentrations of raptors and landbirds ? According to current Wyoming Game and Fish Department Wildlife Observation Form data 6,115 sage grouse have been reported in the IBA area since 1978. ? The Wyoming Sage grouse lek data shows 36 leks within the IBA area. ? According to HawkWatch International, the high numbers of raptors passing through the area ranks the Commissary ridge high among 10 other comparable monitoring efforts in the western U.S. HawkWatch International has documented fall raptor migration in the area for three years, and plans to continue yearly fall migration counts on this important site. ? There is only one Breeding Bird Survey (BBS) route close to the IBA - the Cumberland Route WYO-022. This area is a few miles south of the IBA border, but contains similar high desert sage steppe type habitat found in other parts of the IBA. Therefore, this data represents the types of bird species encountered within the IBA sage brush habitat. It appears by the species list that there is a also water body within the sage habitat along this BBS route. ? These numbers reflect the abundance of the species near the survey route. They are averages of the total counts along the route for the period 1989-1998. Because each survey route is 24.5 mi long, and consists of 50, 3 minute counts along the length of the route, the abundance estimate represents the number of birds that a very good birder would encounter in about 2.5 hours of roadside birding in the area near the BBS route. Only the species that had an abundance estimate greater than zero are displayed here. Birds/route Canada Goose 0.5 Gadwall 1 American Wigeon 1.5 Mallard 0.5 Cinnamon Teal 0.5 Northern Shoveler 1 Northern Pintail 0.5 Northern Harrier 0.5 Ferruginous Hawk 0.5 Golden Eagle 1 American Kestrel 0.5 Prairie Falcon 0.25 Killdeer 7.75 Common Snipe 0.25 Wilson's Phalarope 5 Mourning Dove 6.25 Common Poorwill 0.75 Red-shafted Flicker 1.25 Say's Phoebe 2.25 Eastern Kingbird 0.5 Black-billed Magpie 9 American Crow 0.75 Common Raven 0.25 Horned Lark 15.25 Violet-green Swallow 6 N. Rough-winged Swallow 0.5 Cliff Swallow 0.25 Barn Swallow 9.25 Rock Wren 8.5 House Wren 0.75 Mountain Bluebird 7.75 American Robin 7.5 Sage Thrasher 25.5 Green-tailed Towhee 6 Brewer's Sparrow 22.75 Vesper Sparrow 37.5 Sage Sparrow 4.25 Lark Bunting 4 Savannah Sparrow 0.25 Song Sparrow 2.5 White-crowned Sparrow 0.5 Lazuli Bunting 0.25 Red-winged Blackbird 4.25 Western Meadowlark 37.5 Yellow-head. Blackbird 4.5 Brewer's Blackbird 23.25 Brown-headed Cowbird 1.75 ? Some other data that was discovered in the files of the Kemmerer BLM office gives an idea of bird species found within habitat types in the IBA. This data was collected in 1980-81 and it appears that it has not been entered into a computer or summarized before. Below are a few quick summaries of the species found during these transect surveys in different habitat

Conservation Issues

? Currently, the main potential threat to migrating raptors in the IBA area would be wind farm development. There is currently a large wind farm south of the IBA along the Bear River Divide. Other wind farm proposals are being analyzed for areas within the IBA.
? Fragmentation and destruction of habitat by roads, powerlines, fences, and other human disturbances such as energy development is the main threat to most of the key habitats for bird nesting within the IBA.
? Poor livestock management and overgrazing are potential threats to bird nesting habitat.
? Aspen habitat is threatened by lack of regeneration due to lack of fire, or other human landscape alterations such as grazing, and water table changes.
? Mixed conifer and spruce/fir habitats need to be managed for age class diversity, again due to the absence of fire in the ecosystem.
? Sage-brush habitats need age class diversity, currently there is a problem with many large seral stage stands of sage brush. Prescribed burning, mowing or chemical treatments can set back succession and create new age classes.
? Mountain shrublands need to be protected from overgrazing by livestock.
? Grasslands need to be managed to prevent both overgrazing and shrub encroachment.

Ownership

? Most of this area is managed by the Federal government for multiple uses. The BLM has many different management practices for example: grazing, mining, oil and gas development, right-of-way authorizations (ex. wind energy, powerlines, roads, pipelines), timber harvest, prescribed fire, vegetation treatments (ex. prescribed fired, timber harvest, mowing, chemical treatments), and developed recreation sites.
? The BLM has several management plans in place that address habitat protection for wildlife: the Wheat Creek Wildlife Habitat Area, the Raymond Mountain Wilderness Study Area and ACEC, the Thomas Fork Habitat Management Plan (HMP), the Overthrust HMP, the Moxa Arch Mitigation Plan, and the Lynx Analysis Unit.
? The Forest Service and Wyoming Game and Fish have similar issues as the BLM. Fossil Butte National Monument has the most restrictive and protective management practices, for example no grazing or oil and gas development is allowed. However there is an active fossil quarry on the site.

Habitat

The main aspect that made this IBA noteworthy is its high concentration of migrating raptors in the fall as discovered and documented by HawkWatch in 2001. According to Hawkwatch, ?Migrating raptors frequently concentrate along north-south aligned mountain ranges for several reasons. Many raptor species seek to save energy on their long journeys by taking advantage of wind-driven updrafts that routinely occur along such ranges. In western North America, strong updrafts frequently occur along the western flanks of north-south ranges as predominately westerly winds are deflected upward by the montane topography. Long north ?south ranges also serve as navigational aids by forming a ?leading line? that raptors can follow enroute to their seasonal destination. In many cases, especially in arid landscapes such as the Great Basin, montane ridges may also attract migrants because they provide the only available forested habitat. For species such as the accipiter hawks, forest cover may be a necessary requirement to provide suitable stopover and foraging habitat.? The Commissary Ridge and its neighboring ridges, the Sublette Range, the Wyoming Range, and the Bear River Divide form such a north-south corridor. ? There are other diverse habitat types within Commissary Ridge Raptor Migration Route IBA that offer breeding and wintering habitats to birds. The key primary and secondary habitats according to the GAP vegetation data area are listed below along with the approximate acres of each within the IBA area. (See attached maps for location of vegetation types.) Primary Vegetation Cover Type Acres Alpine exposed rock/soil 6152.1 Aspen forest 65571.9 Basin exposed rock/soil 2694.5 Clearcut conifer 608.1 Desert shrub 2363.0 Douglas fir 13831.6 Dry-land crops 2242.0 Forest-dominated riparian 42.7 Greasewood fans and flats 14.5 Irrigated crops 2596.6 Juniper woodland 4906.3 Lodgepole pine 123582.0 Mesic upland shrub 444.1 Mixed grass prairie 372.8

Land Use

This large area is under many different managing agencies (Fossil Butte National Park, BLM, Bridger Teton National Forest, and Wyoming Game and Fish Department) and therefore has many various land uses. The agencies will have to work together and individually to maintain the site integrity.
Most of this area is managed by the Federal government for multiple uses. The BLM has many different management practices for example: grazing, mining, oil and gas development, right-of-way authorizations (ex. wind energy, powerlines, roads, pipelines), timber harvest, prescribed fire, vegetation treatments (ex. prescribed fired, timber harvest, mowing, chemical treatments), and developed recreation sites.
The BLM has several management plans in place that address habitat protection for wildlife: the Wheat Creek Wildlife Habitat Area, the Raymond Mountain Wilderness Study Area and ACEC, the Thomas Fork Habitat Management Plan (HMP), the Overthrust HMP, the Moxa Arch Mitigation Plan, and the Lynx Analysis Unit.
The Forest Service and Wyoming Game and Fish have similar issues as the BLM. Fossil Butte National Monument has the most restrictive and protective management practices, for example no grazing or oil and gas development is allowed. However there is an active fossil quarry on the site.