fragility
Cerulean warbler | Bay-Breasted Warbler | Light-bellied Brent Goose | Swainson’s Thrush | Ivory Gull | White-tailed Ptarmigan | American Bittern | Mountain Bluebird | Brown Creeper | Yellow-billed Cuckoo | American Three-toed Woodpecker | Baird’s Sparrow | Black Swift | Black Tern | Brewers Sparrow | Burrowing Owl | Chestnut-collared Longspur | Columbian Sharp-tailed Grouse | Common Loon | Ferruginous Hawk | Fox Sparrow | Grasshopper Sparrow | Greater Prairie-Chicken | Green-tailed Towhee | Harlequin Duck | Lark Bunting | Lesser Prairie-chicken | Lewis’s Woodpecker | Lincoln’s Sparrow | Loggerhead Shrike | McCowns Longspur | Mountain Plover | Northern Harrier | Northern Goshawk | Pinyon Jay | Purple Martin | Pygmy Nuthatch | Ruffed Grouse | Sage Sparrow | Short-eared Owl | Trumpeter Swan | Wilson’s Warbler | Yellow-billed Loon | American Oystercatcher | Black Oystercatcher | Buff-breasted Sandpiper | Hudsonian Godwit | Marbled Godwit | Red Knot | Red-Necked Phalarope | Sanderling | Western Sandpiper | Whimbrel | Dunlin | Wilson’s Phalarope
The action plans are extremely rich sources of information.
Cerulean warbler (Dendroica cerulea)
Cerulean warbler, Dendroica cerulea (Wilson), is a wood warbler in the Subfamily Parulinae of the Family Emberizidae, Order Passeriformes. No controversial or unsettled issues exist in the taxonomy of this bird. The numbers of cerulean warblers are declining at rates comparable to the most precipitous rates documented among North American birds by the cooperative Breeding Bird Survey. Recent evidence suggests that events on breeding, stopover, and wintering grounds are implicated in this decline. However, no detailed life history study of the species exists. This status assessment is an attempt to assemble what is known of the species into a form that will enable biologists in the U.S. Fish and Wildlife Service to make a decision on whether or not to propose listing of the species under the Endangered Species Act. The report will also help the Service and others establish priorities for monitoring; research; and habitat protection, restoration, and management that will conserve this species. Historical data on the occurrence and abundance of the species are sparse and do not permit estimation of total numbers. However, it is clear that this species was a conspicuous and abundant bird throughout the Ohio and Mississippi River valleys in the past century. Currently the birds are much less numerous in areas where formerly they were abundant. (text derived from SAP).
Bay-Breasted Warbler (Dendroica Castanea)
The Bay-breasted Warbler is a neotropical migrant that inhabits boreal coniferous forests in a broad band, primarily, across central and eastern Canada. It breeds in northern spruce-fir forests, feeding and nesting in the dense foliage of these conifers. It winters in Panama and northern South America. Males and females are fairly large relative to other members of the genus Dendroica, being 13 to 14 cm long and weighing about 13 g. Bay-breasted Warbler numbers have been reported to dramatically increase and decrease in synchrony with outbreaks and declines of the spruce budworm (Choristoneura fumiferana), a key food item. Its North American breeding distribution is closely correlated with that of spruce and fir in the boreal forest. The greatest threat to the breeding range of the Bay-breasted Warbler is the reduction in the area of old-growth spruce and fir of the boreal forest. Both nesting habitat and food supply (spruce budworm) are at risk when reductions or alterations of these forest areas occurs. Spraying insecticides to control spruce budworm can have direct toxic affect on this Warbler (inhibition of brain acetylcholinesterase activity). Winter habitat degradation and loss is also a threat, as commercial and residential development activity continues to reduce the forested habitats in the tropics. (text derived from SAP)
Light-bellied Brent Goose (Branta bernicla hrota)
The East Canadian High Arctic (ECHA) Light-bellied Brent Goose Branta bernicla hrota breeds in Canada’s eastern Queen Elizabeth Islands with the great majority wintering on the coastline of the island of Ireland and smaller numbers on the Channel Islands and the northern coasts of France and Spain. It is protected under the general provisions of the European Union Directive on the Conservation of Wild Birds (79/409/EEC) (Birds Directive), the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) and the Canada–U.S. Migratory Birds Convention 1916. The population is listed under Category A2 of the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA), because there are only between 10,000 and 25,000 individuals in the population. The key threats to this population are habitat loss/degradation, natural disasters, changes in native food species dynamics (e.g. Zostera wasting disease) and pollution (directly through oil/chemical spills or indirectly through the potentially catastrophic effects and impacts of climate change). Other less important threats include illegal persecution, accidental mortality, disturbance, invasive alien species (e.g. Spartina encroachment in estuaries or potential competition with other geese on the breeding grounds) and intrinsic factors (restricted range, low productivity, climate-caused periodic non-production). In light of the small number of countries involved, and given the history of cooperative international conservation and research initiatives, it has been deemed appropriate to take an international approach to the conservation of this population, with the production of an AEWA International Single Species Action Plan (SSAP).. (text derived from SAP)
Swainson’s Thrush (Catharus ustulatus)
The Swainson’s Thrush is one of the North American spotted thrushes within a guild of ground- foraging, mainly insectivorous birds (Noon 1981), and is described as a complete long-distance (nearactic-Neotropical) migrant. It breeds in the western and northern U.S. to Alaska and Canada, and winters from southern Mexico to northern Argentina. Across its breeding range, this species occurs from sea level to 2,000 m (6,562 ft) or higher, and is strongly associated with coniferous forests or conifer components in mixed fo rests. The nests of the Swainson’s Thrush are most frequently found in the understory 1m to 2.4 m (3.2 ft to 7.9 ft) above ground (Evans Mack and Yong 2000). In the Northeast and Midwest, their nests are most commonly found in understory balsam fir (Abies balsamea), spruce, or eastern hemlock (Tsuga canadensis) (Bull 1974, Harrison 1975, D. Flaspohler pers. comm. 2003). Although there are conflicting regional differences, the Swainson’s Thrush is considered a generalist regarding forest succession and is found in both mature forests and early successional habitats. Although not listed nationally or regionally as a species of conservation concern, local population declines warrant attention. The Swainson’s Thrush is currently listed in Wisconsin as a Species of Special Concern, and in Pennsylvania as a Candidate Rare Species. It is a Regional Forester’s Sensitive Species on one National Forest, the Chequamegon-Nicolet in Wisconsin. (text derived from SAP)
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Ivory Gull (Pagophila eburnea)
The Ivory Gull (Pagophila eburnea) is a medium-sized gull that breeds in the High Arctic, and is the sole representative of its genus. It is pelagic for much of the year, wintering in cold northern waters, and is associated with pack ice year round. It is currently listed as a species of Special Concern under the federal Species at Risk Act (SARA). However, recent breeding colony surveys suggest that Ivory Gulls have declined by up to 85 % in Canada since the 1980s. While little is known about the anthropogenic activities that may affect Ivory Gulls in Canada, potential threats that may be contributing to mortality include hunting, disturbance, habitat degradation, and oiling. However, identifying and addressing potential threats is extremely difficult, due to the lack of information on the species’ breeding biology, winter ecology, life history and behaviour, as well as a lack of information on the extent of the threats themselves. (text derived from SAP)
Long-billed Curlew (Numenius americanus)
The historical breeding range of Long-billed Curlews (Numenius americanus) was the western U.S. and the southern Canadian Prairie Provinces from California north to British Columbia and east to southern Manitoba and Wisconsin, northern Iowa and eastern Kansas. However, this breeding distribution has contracted and Long-billed Curlews have lost about 30% of their historical range. The eastern edge of the current breeding range is the western Great Plains from the Texas panhandle north throughout southwestern and south central Saskatchewan. Long-billed Curlews currently winter along the southwestern U.S. coast from central California, southern Texas and Louisiana south along both of Mexico’s coasts to Guatemala, and are casual along the Atlantic coast north to New Brunswick, the southeastern South Carolina and Florida coasts, and the West Indies. Long-billed Curlews are federally protected in the U.S., Canada, and Mexico under the Migratory Bird Treaty Act. In the U.S., they are listed as a U.S. Fish and Wildlife Service Bird of Conservation Concern: nationally, in five U.S. Fish and Wildlife Service regions, and in several Bird Conservation Regions. (text derived from SAP)
White-tailed Ptarmigan (Lagopus leucura)
The greatest threat to the long-term survival of ptarmigan populations in Region 2 is global climate change, which may lead to a gradual loss of alpine habitats as the treeline moves upward in response to large-scale atmospheric temperature changes. More immediate and localized threats include grazing, mining, water development, and recreation. While alpine ecosystems are hardy and resilient to natural environmental factors, they are particularly vulnerable to human-related disturbances and may require decades, if not centuries, to recover from such disturbances. Although substantial progress has been achieved in developing techniques to restore damaged alpine landscapes, this technology is still not capable of restoring alpine plant communities to their pre-disturbance condition. The single most important feature of habitats used by ptarmigan in Region 2 is the presence of willow (Salix spp.), which is their primary food source from late fall through spring. Any activity that reduces the distribution and abundance of willow will likely have negative consequences to ptarmigan. The primary information needed for effective conservation of white-tailed ptarmigan in Region 2 is a clearer understanding of how the species responds to alterations in habitat and changes in environmental conditions. The natural processes that perpetuate alpine ecosystems are still intact. Consequently, human intervention is not necessary other than to insure that these natural processes are not disrupted. (text derived from SAP)
American Bittern (Botaurus lentiginosus)
The loss and degradation of freshwater, wetland habitats appears to be the biggest threat facing bittern populations. Much habitat loss has occurred because of draining seasonal and ephemeral wetlands for conversion to agricultural use (e.g., crop production, livestock grazing). In addition, wetlands are often degraded by agricultural activity (e.g., livestock grazing) on adjoining uplands. Without a large vegetative buffer, wetland value to bitterns may be decreased, and wetlands may suffer from chemical contamination due to runoff, siltation, and eutrophication. The loss of a vegetative buffer zone may lead to increased predation at bittern nests, and degradation of buffer zones may decrease foraging success and lead to site abandonment. Surveys for bitterns in Midwestern states have revealed apparently suitable habitat that was not used by breeding bitterns. This suggests that habitat degradation and/or human disturbance may be responsible for some regional declines in bittern abundance. Loss of wintering habitat (i.e., wetlands along the Gulf of Mexico coastal plain) has also been cited as a potential threat to American bitterns. Enhancing wetland habitats and conducting research into the species’ breeding biology and life history may aid the conservation of American bitterns. Currently, there is very little information available on foraging behavior, causes of variance in reproductive success, adult and juvenile survival, and habitat use during migration. In addition, further information on bittern abundance and distribution is needed. Dedicated bittern call-playback surveys appear to be the only reliable method for censusing bitterns on the breeding grounds. (text derived from SAP)
Mountain Bluebird (Sialia currucoides)
Mountain bluebird (Sialia currucoides) populations have been relatively stable across their range over the past 40 years. However, local declines have apparently occurred in some areas along the eastern foothills of the Rocky Mountains, as well as in the Black Hills of South Dakota and Wyoming. Mountain bluebirds breed in a variety of habitats characterized by open ground or short grass with nearby tree cavities for nesting. Consequently, the primary conservation consideration for mountain bluebirds is the availability of mature trees in proximity to open habitat. A large number of studies have now shown that mountain bluebirds show relatively strong affinities to habitats impacted by fire and logging; their abundance typically increases significantly in such habitats. It is likely then that widespread fire suppression in western forests has negatively impacted the abundance of mountain bluebirds. While logging may create nesting habitat for mountain bluebirds, there are limited data suggesting that nesting success may be low in logged areas. A better understanding of the relative quality of mountain bluebird breeding habitat would simplify habitat management efforts for this species. For example, studies of bluebird breeding success in natural cavities in recently burned forest, on logged sites, and in undisturbed situations would help to clarify the role of these habitats in determining population viability. (text derived from SAP)
Brown Creeper (Certhia americana)
Brown creepers are known to have relatively strict breeding habitat requirements; they prefer to nest in areas with an abundance of mature and old-growth trees and high canopy cover. Additionally, brown creepers are known to be sensitive to forest management practices such as heavy (e.g., clearcut) logging and the habitat-fragmenting effects that it often produces. Consequently, brown creepers may serve as an important indicator of forest health in areas where forest habitats are actively managed. Studies throughout North America have shown that most types of logging (e.g., clear-cuts, salvage, partial) have negative consequences for local creeper abundance. In some cases, creepers completely abandon logged sites, likely because of the loss of large, mature and old-growth trees that provide both foraging and nesting sites (peeling bark). Logging may also reduce local habitat quality by creating fragmented forest patches and by increasing areas of edge habitat. Brown creepers are a forest interior species, typically nesting far from forest edges. Thus, they are sensitive to fragmentation and consequent increases in edge habitats. (text derived from SAP)
Yellow-billed Cuckoo (Coccyzus americanus)
In western North America, yellow-billed cuckoos (Coccyzus americanus) have undergone catastrophic declines; the eastern subspecies has undergone less rapid declines in most areas since approximately 1980. Direct loss and degradation of low-elevation riparian woodland habitats have been cited as the primary causes for the declines in yellow-billed cuckoos in the western portion of the range. Factors contributing to habitat loss and degradation include alteration of flow schemes in rivers and streams; diversion of water for agricultural and municipal purposes; urban expansion; livestock grazing, which affects understory vegetation and cottonwood/willow recruitment; and pesticide applications which decrease local food supplies and potentially induce toxic accumulations in cuckoos. In the east, the reasons for the now widespread declines are less clear. One potential factor contributing to declines across this species’ range in North America is the loss of forested habitat on its wintering grounds in South America. However, little is known of its ecology or distribution in South America, and this remains an area in need of further research. While it is clear that western populations of yellow-billed cuckoos have undergone drastic declines in both range and abundance, it is important to note that cuckoos are also declining significantly in the east (from the Great Plains eastward), and that this decline has gone largely unnoticed by most regulatory agencies and conservation organizations (e.g., Partners In Flight). This may partly be explained by the fact that cuckoos are still relatively common in many forested habitats in the east, and thus they have not yet registered as a species of concern. However, given the significant recent declines even in the core of their range (e.g., Oklahoma and Kansas), research into the causes of these declines should be initiated while the species is still tractable. Many populations in the west are now so small and isolated that gaining insight into population declines there will be extremely difficult. The identification of the factor(s) contributing to declines in yellow-billed cuckoos on the Great Plains would be a key piece of information in helping to develop a regional management plan. (text derived from SAP)
American Three-toed Woodpecker (Picoides dorsalis)
American three-toed woodpeckers (Picoides dorsalis) are not federally listed under any conservation category in the United States or Canada. The limited population trend data available from Breeding Bird Surveys and Christmas Bird Counts suggest no clear pattern of decline or increase. However, because of the species’ low abundance and retiring habits, it is not well sampled with such range-wide population sampling efforts. Consequently, data on which to assess population trends of American three-toed woodpeckers are currently lacking at the regional and range-wide scales. American three-toed woodpeckers are widely considered barometers of the health of old-growth conifer forests in North America. This relationship is largely the result of the species’ apparent dependence on mature and old-growth conifer forests. However, areas of disturbed forests (e.g., recent burns, beetle infestations) have also been widely cited as important habitat. Unfortunately, there is little information available on how these two habitat elements may interact in regulating local populations of woodpeckers. In addition, the extent to which American three-toed woodpeckers utilize habitats (either for foraging or nesting) other than spruce-fir and lodgepole pine in the southern Rocky Mountains remains poorly known. (text derived from SAP)
Baird’s Sparrow (Ammodramus bairdii)
Historically, the primary threats to Baird’s sparrows have been the conversion of native grassland to cropland, as well as the degradation of remaining native grasslands on the breeding grounds, along migratory routes, and on wintering grounds. The total area of mixed-grass prairie in the northern Great Plains has declined dramatically since the mid-1800’s. Suppression of prairie fires and invasion of shrubs and exotic grasses have also been cited as problems on the breeding ground of Bairds sparrows. Little is known of the species’ distribution and habitat use during the winter, but overgrazing is thought to have contributed significantly to the degradation of this habitat. Thus, the primary threats to healthy populations of Baird’s sparrows appear to be the result of habitat loss/degradation; these may be overcome with proper habitat management schemes. (text derived from SAP)
Black Swift (Cypseloides niger)
Historically, black swifts (Cypseloides niger) have been one of the most poorly understood species of birds in North America. Although some information on the ecology and distribution of black swifts has recently become available, there remains considerable uncertainty regarding their distribution and life history traits (e.g., survival, dispersal). Swifts appear to be a relatively long-lived species with a fixed clutch size of one egg and an unusually prolonged and late breeding season. Nestling growth is slow, with the nestling typically leaving the nest 47 to 50 days after hatching. Black swifts do not hold any special conservation status in Canada. In the United States, black swifts are considered a Species of Conservation Concern by the U.S. Fish and Wildlife Service, and a Sensitive Species by the U.S. Forest Service. Black swifts are also a National Audubon Society WatchList Species, and they are a Priority Species within many state and regional Partners in Flight conservation plans. Although there is currently little direct information on the factors affecting black swift population viability, the main threats appear to be the lack of late summer water runoff, which affects the suitability of nest/colony sites, and decreased local food supplies. Although the hypothesis is speculative, forest management practices, such as logging, road building, and cattle grazing may reduce late summer water flows by reducing water retention. These practices, together with fire suppression, typically decrease local vegetative diversity and may therefore negatively affect food supplies (flying insects and arthropods). (text derived from SAP)
Black Tern (Chlidonias niger surinamensis)
The black tern (Chlidonias niger surinamensis) still occupies most of its former range. The continental population likely numbers in the low to mid hundreds of thousands and appears stable within the habitat that remains. However, given the severity of previous declines, conservation of the black tern still warrants serious concern. Primary conservation needs include tightening wetland protection laws, enhancing habitat protection programs and developing better population monitoring strategies. Loss of remaining wetland and grassland habitats to agriculture or other development is the greatest threat to black tern conservation. The threat beyond that of direct habitat loss is that cumulative impacts of drainage might degrade the natural heterogeneity of wetland landscapes to the point that black terns no longer use the remaining wetlands. Further loss of remaining grasslands is also a threat because wetlands in agrarian landscapes are at high risk of drainage. The U.S. Supreme Court in 2001 issued a judgment dubbed the SWANCC decision that effectively removed protection from 80 to 98 percent of wetlands in Region 2 that were formally protected under Section 404 of the Clean Water Act. The net result of the SWANCC decision has left the “Swampbuster†provision of the Food Security Act as the last line of defense for protecting wetlands that provide habitat for black terns. This is important because federal policy that drives land use change may place more pressure on public lands (e.g., national grasslands) to provide suitable habitat for species of concern. Some citizens who opposed grazing on public lands now consider it a new icon for conservation because ranchers that maintain profitability on native range are less likely to convert wetlands and grasslands to croplands. (text derived from SAP)
Brewers Sparrow (Spizella breweri)
The Brewer’s sparrow (Spizella breweri) is a sagebrush obligate that is often the most abundant songbird in sagebrush shrubsteppe habitats. This assessment focuses on the S. b. breweri subspecies, which is found in USDA Forest Service (USFS) Region 2. Brewer’s sparrow is considered globally “secure†by the Natural Heritage Program because of its wide distribution across North America. However, according to the Breeding Bird Survey, Brewer’s sparrow populations have declined by over 50 percent during the past 25 years. Brewer’s sparrow populations within the states of USFS Region 2 have exhibited similar long-term declines; in fact, declines in Colorado and Nebraska have outpaced national trends. In South Dakota and Kansas, the species is considered “imperiled†by the states’ natural heritage programs. The Brewer’s sparrow is listed as a priority bird species in the Colorado and Wyoming Partners in Flight bird conservation plans and as a species of special concern by the U.S. Fish and Wildlife Service. As a result of these regional declines and the species’ vulnerability to habitat loss, USFS Region 2 lists the Brewer’s sparrow as a regional sensitive species.
Reported Brewer’s sparrow population declines on the breeding areas are likely linked to extensive alteration of sagebrush (Artemisia spp.) shrubsteppe habitat. Though widespread, this habitat constitutes one of the most endangered ecosystems in North America due to extensive, ecologically transformative influences of livestock grazing, followed by alteration of natural fire regimes and invasion by exotic plant species, especially cheatgrass (Bromus tectorum). Loss and fragmentation of habitat due to agricultural, urban, suburban, energy, and road development also threaten the species. (text derived from SAP)
Burrowing Owl (Athene cunicularia)
The status of burrowing owls in Region 2 is closely tied to that of prairie dogs (Cynomys spp.), because of the owls requirement for mammal-excavated burrows. Continued loss of prairie dog colonies through active eradication, habitat loss, or disease will negatively impact burrowing owl population viability. Although declines of burrowing owls in most of Region 2 are not yet as dramatic as at the limits of its range (e.g., in Canada), most of the states in Region 2 have tentative evidence for recent and ongoing declines. Recent genetic studies, however, suggest that burrowing owls are panmictic (genetically connected by extensive dispersal) and do not yet show evidence of genetic isolation among populations. Strong dispersal ability means that reversal of unfavorable conditions should result in re-establishment of burrowing owls in suitable habitat via dispersal. Very little is still known about migratory patterns, except a general leapfrog pattern whereby the most northerly populations, such as those in Canada, tend to move furthest south to wintering grounds in Mexico. More southerly populations, such as those in Colorado, appear to engage in partial migration, with some individuals staying on the breeding grounds through most or all of some winters. Little is known about threats on the wintering grounds outside Region 2. Matrix-based demographic analyses suggest that the survival rate of adult females is a key element in the population dynamics of burrowing owls. Standardized surveys and ongoing research should provide the basis for improved assessment of the status of burrowing owls in the region. (text derived from SAP)
Chestnut-collared Longspur (Calcarius ornatus)
Chestnut-collared longspurs (Calcarius ornatus) are locally abundant breeding birds of the shortgrass and mixed-grass prairies of the Great Plains. In Region 2 USDA Forest Service lands, they commonly breed only on the Pawnee National Grassland in Colorado and the Thunder Basin National Grassland in Wyoming. They winter mostly south of Region 2. Continent-wide, the population of chestnut-collared longspurs has been declining at 2.0 percent per year (1966 – 2001 Breeding Bird Survey [BBS]; Sauer et al. 2001). The greatest declines, however, occurred long before the initiation of the BBS: “When the northern prairies became the great wheat-producing region of the continent, the amount of grassland available for the Chestnut-collar was reduced proportionately†(Fairfield 1968). The chestnut-collared longspur is ranked by various state, federal, and private conservation organizations as a grassland “species of concern,†“high priority,†“imperiled,†with “pressing needs,†“state imperiled,†or a species of “conservation concern.†Loss of native mixed-grass and shortgrass prairies to agriculture and development on the breeding grounds—and on the wintering grounds—is the greatest threat to chestnut-collared longspurs. Although most of the rangeland loss to agriculture was historical, more recent losses are not insignificant. In Colorado, for example, 3.8 percent of the shortgrass and mixed-grass prairie east of the Rockies was lost to agriculture and urban expansion from 1982 to 1997 (Seidl et al. 2001). Habitat loss from increasing oil and gas development, especially in Wyoming, and the associated negative impacts of disturbance and fragmentation also pose a threat to chestnut-collared longspurs. Fire suppression, increasing recreational activities, and the use of pesticides are somewhat lesser threats. Any absolute changes in first-year survival or fertility rates will have major impacts on population dynamics.(text derived from SAP)
Columbian Sharp-tailed Grouse (Tympanuchus phasianellus columbianus)
The Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus; CSTG) is one of six existing subspecies of sharp-tailed grouse in North America. It is endemic to big sagebrush (Artemisia tridentata), shrubsteppe, mountain shrub, and riparian shrub plant communities of western North America. The subspecies currently occupies less than 10 percent of its historic range, with only three metapopulations remaining in central British Columbia, southeastern Idaho and northern Utah, and northwestern Colorado and south-central Wyoming. Within Region 2 of the USDA Forest Service (USFS), this grouse formerly occurred in as many as 22 counties in western Colorado and in portions of 11 counties in west-central, southwestern, and south-central Wyoming. Today, viable populations occur in only three counties in Colorado and one county in Wyoming. Attempts are being made to reintroduce CSTG to previously occupied habitats in southwestern and north-central Colorado. Approximately 68 percent of the occupied habitat in Region 2 is on private lands, and only 4 percent is on lands administered by the USFS. The CSTG has been petitioned twice for listing under the Endangered Species Act. Under both petitions, the finding was not warranted. USFS Region 2 and the state offices of the Bureau of Land Management in Colorado and Wyoming have designated the CSTG a sensitive species. Both the Wyoming Game and Fish Department and Colorado Division of Wildlife list it as a species of special concern.. (text derived from SAP)
Common Loon (Gavia Immer)
The Common Loon (Gavia immer), one of five loon species worldwide, is a highly visible resident of our North American waters. Its high profile nature keeps it squarely in the forefront of many aquatic-based conservation efforts. Public appeal for the loon is fully apparent when considering the number of non-governmental organizations dedicated to its conservation. Loons are well-known symbols of the northern wilderness; however, with increasing human presence and activity in formerly pristine areas, they are also serving as indicators of aquatic health. Landscape-level alterations in aquatic environments have led to serious threats throughout the loon’s life cycle, yet individuals and populations are resilient and appear to have the ability to acclimate to certain habitat disturbances, sometimes within the same generation. For loons to successfully transition from a wilderness setting to one that is frequently exploited by humans will depend on our ability to better understand factors limiting their populations. This Status Assessment and Conservation Plan outlines knowledge-to-date on (1) natural history, (2) habitat requirements, (3) population distribution, estimates and trends, (4) threats to its survival and well being, (5) monitoring activities, (6) protection status, and (7) detailed strategies for safeguarding population health. Loons are our “coal mine canaries†for northern lakes; their ability to maintain healthy populations across their current range reflects favorably on our ability to maintain the integrity of aquatic ecosystems. (text derived from SAP)
Ferruginous Hawk (Buteo regalis)
The primary threats to the ferruginous hawk include lack of secure nest substrates, lack of suitable prey species, human disturbance during the reproductive period, lack of suitable habitat surrounding nest sites, and threats to survival of adult hawks. Most of these primary threats, as well as lesser threats, originate from the loss (to cultivation and urbanization) of historically occupied habitat, or alteration (through overgrazing by domestic livestock, altered fire regimes, and conversion to less diverse landscapes) that leads to a significant reduction in small mammal populations, the primary food source of ferruginous hawks. While all threats operate on a local scale, it should be understood that habitat loss and degradation occur on a broad-scale, and that curbing urban sprawl and retaining large, intact tracts of grassland and shrub-steppe present the major challenge to preserving viable populations of ferruginous hawks. (text derived from SAP)
Fox Sparrow (Passerella iliaca schistacea)
Species conservation assessments produced as part of the Species Conservation Project are designed to provide forest managers, research biologists, and the general public with a thorough discussion of the biology, ecology, conservation status, and management of certain species, based on available knowledge. The assessment goals limit the scope of the work to critical summaries of scientific knowledge, discussion of broad implications of that knowledge, and outlines of information needs. In our assessment we do not develop specific management recommendations for the fox sparrow, but we do try to provide ecological background upon which its management can be based. We also focus on the consequences of changes in the environment that result from management (i.e., management implications). Furthermore, we cite management recommendations proposed elsewhere and, when management recommendations have been implemented, we report the results of the implementation. (text derived from SAP)
Grasshopper Sparrow (Ammodramus savannarum)
Grasshopper sparrow populations have declined by over 60 percent during the past 25 years. The U.S. Fish and Wildlife Service lists the grasshopper sparrow as a species of special concern, and the Florida subspecies is listed as federally endangered. Within the states of USDA Forest Service Region 2, which represent the core of this species breeding range, grasshopper sparrow populations have also exhibited long-term declines. Declines in Colorado and South Dakota have outpaced national trends. In Colorado and Wyoming, the species is considered “vulnerable” by the S/B Natural Heritage Program. The grasshopper sparrow is listed as a priority bird species in the Colorado and Wyoming Partners in Flight bird conservation plans. (text derived from SAP)
Greater Prairie-Chicken (Tympanuchus cupido)
The geographic distribution and abundance of greater prairie-chickens (Tympanuchus cupido) have fluctuated dramatically during the last 200 years following settlement by people of European descent, but in recent decades virtually all changes have resulted in reduced abundance and smaller, more fragmented distributions. One subspecies of the greater prairie-chicken, the heath hen (T. c. cupido), became extinct in 1932. A second subspecies, Attwater’s prairie-chicken (T. c. attwateri), is federally listed as endangered and is close to extinction. The remaining subspecies (T. c. pinnatus) is the only subspecies found in Region 2, and it is locally extinct, threatened, endangered, or harvestable, depending on location. Primary conservation elements to be considered in Region 2, and in other portions of the species’ distribution, include practices associated with grazing, farming, burning, and mowing of potential and occupied habitat, and the impacts of development, roads, power lines, fences, oil and gas development, tree planting/encroachment, off-road vehicles, and harvest. It is also important to recognize that drought exacerbates the impacts of these practices. The inappropriate timing and intensity of livestock grazing, in particular, can cause widespread degradation of habitat for greater prairie-chickens by homogenizing the essential heterogeneous grassland landscape that they prefer. Features associated with human development (e.g., communities, roads, land use changes, herbicides) also contribute to habitat fragmentation, alter predation dynamics, and introduce disturbance and mortality factors. (text derived from SAP)
Green-tailed Towhee (Pipilo chlorurus)
The major threat to green-tailed towhee populations in Region 2 is the long-term degradation of shrub-dominated habitats through the effects of fire suppression, livestock grazing, and the introduction of non-native annual grasses. The interaction of these factors over the past century has reduced the heterogeneity of shrubland habitats at local and landscape scales. In lower montane and foothill areas, intense fire suppression and livestock grazing facilitate the uniform invasion of woody vegetation (i.e., sagebrush in shrubsteppe, junipers in foothill shrubland, and pines in shrub-pine savanna), which reduces the mosaic quality of shrubland habitats that green-tailed towhees prefer. Combined with dense, even coverage of introduced non-native grasses, these factors also promote intense wildfires that remove all shrubs and prevent shrub regeneration in burned areas, making these habitats unusable by green-tailed towhees. In mid-high elevation coniferous forests, fire suppression has decreased the variation in post-fire seral stages, and thus decreased habitat availability on a landscape scale. Mining and oil and gas development represent important mechanisms of habitat fragmentation on the shrubsteppe landscape, while off-road vehicle recreation and urban development increasingly threaten to degrade and fragment shrubland habitats, especially in the foothills of the Colorado Front Range. (text derived from SAP)
Harlequin Duck (Histrionicus histrionicus)
Harlequin ducks (Histrionicus histrionicus) have been the focus of management actions in eastern North America, the Pacific Northwest, and in the Rocky Mountain states due to concern over declining populations. Relative to other species of ducks, harlequin ducks occur at low population densities and exhibit high breeding site fidelity, low reproductive rates, and delayed reproduction. All of these traits contribute to making harlequin duck populations particularly slow to recover from habitat degradation or loss, or other factors that may lower duck survival (e.g. marine pollution). The species apparently bred in small numbers in Colorado in the late 1800s but subsequently became extirpated there, likely as a result of habitat degradation related to mining activities (e.g., timber harvesting, contamination of water supplies). More recently, harlequin ducks have disappeared from former breeding sites in Idaho and Montana. (text derived from SAP)
Lark Bunting (Calamospiza melanocorys)
The Global and U.S. National Heritage Programs give the lark bunting (Calamospiza melanocorys) a conservation ranking of G5 and N5 respectively, which indicates that the species is widespread and secure. The Canadian National Heritage Program designates the lark bunting as N4, which indicates the species is uncommon but apparently secure with some cause for concern over the longterm (NatureServe 2005). The lark bunting is a Management Indicator Species on the Pawnee National Grassland, which is managed by the Rocky Mountain Region (Region 2) of the USDA Forest Service (USFS). A recent study suggests that lark bunting populations on the Pawnee National Grassland may be declining (Yackel Adams et al. in revision), but the supporting data are not conclusive. Our matrix model suggests that survival of adult lark buntings has the greatest impact on population growth; adult survival rate data are needed in the Pawnee and other areas of its range to validate these estimations. Within Region 2, the greatest threats to lark buntings include habitat loss and habitat fragmentation due to conversion of native grassland to cropland, urbanization, and oil and gas extraction. The World Wildlife Fund classifies most breeding habitats of lark buntings as critical or endangered, with conversion to cropland being the major cause of habitat loss. While lark buntings will nest in some agricultural fields, activities such as plowing, tilling, discing, mowing, and use of pesticides can be very harmful during the nesting period. Human population growth, particularly along the Front Range of Colorado, will likely put increasing demands on lark bunting habitat over the next several decades as grassland is converted to a suburban environment. Current and future increases in oil and gas extraction will continue to fragment and degrade lark bunting habitat in Wyoming and Colorado, and the impacts of these activities will need to be assessed. (text derived from SAP)
Lesser Prairie-chicken (Tympanuchus pallidicinctus)
The overall distribution of the lesser prairie-chicken (Tympanuchus pallidicinctus) has declined an estimated 92 percent since settlement by people of European descent and an estimated 78 percent since the early 1960s. Concurrent with this decrease in occupied range, numbers of lesser prairie-chickens have declined at least 90 percent since European settlement, resulting in smaller, more isolated populations. As a consequence of these declines, the lesser prairie-chicken is a candidate for federal listing as a threatened or endangered species. The major threats to the lesser prairie-chicken in USDA Forest Service Region 2 are the loss, fragmentation, and degradation of habitat on both private and public lands. Conversion of native prairie habitat increasingly isolates populations, elevating the risk of localized extirpations and leading to an erosion of metapopulation viability. Populations throughout the species’ range are vulnerable to land use practices that degrade or eliminate nesting and brood-rearing areas.. (text derived from SAP)
Lewis’s Woodpecker (Melanerpes lewis)
Lewis’s woodpecker (Melanerpes lewis) is a locally common but patchily distributed woodpecker species usually seen in open forests of western North America. The combination of its sporadic distribution, its diet of adult-stage free-living insects (primarily aerial), its preference to nest in burned landscapes, and its variable migratory behavior makes it a unique member of New World woodpeckers. The Rocky Mountain Region (Region 2) of the USDA Forest Service lists the Lewis’s woodpecker as a sensitive species. Region 2 populations are most strongly represented in south-central Colorado during the winter and throughout Colorado, eastern Wyoming, and the Black Hills of South Dakota during the breeding season. Possible threats to its conservation include the following human-induced changes to the environment: use of agricultural pesticides, introduction of non-native cavity-nesting bird species, suppression of fire, and alteration of natural stream flow patterns. These management actions may affect the structure, availability, and quality of the species’ breeding habitats. Primary conservation elements and management considerations include the retention of large snags and the creation of opportunities for snag recruitment (preferably in clumps), the maintenance of understory shrub communities, and the reduction of exposure to agricultural pesticides. Additional habitat considerations include allowing wildfires to burn in lower montane conifers for the creation of burned forest habitat, and managing stream flow patterns and herbivory to promote natural recruitment of cottonwood seedlings, thus retaining and encouraging the development of mature riparian cottonwood woodlands. (text derived from SAP)
Lincoln’s Sparrow (Melospiza lincolnii)
The Nature Conservancy classifies the Lincoln’s sparrow (Melospiza lincolnii) as G5, meaning the species’ rangewide status is demonstrably secure, although it may be rare in parts of its range, especially at the periphery. Overgrazing is possibly the most substantive impact to Lincoln’s sparrows in the U.S. Forest Service, Rocky Mountain Region (Region 2). Overgrazing decreases the volume of vegetation and alters hydrologic regimes, and it contributes to increased predation rates and lower abundances of Lincoln’s sparrows. Recreation within subalpine zones of Region 2 forests can also have significant impacts to Lincoln’s sparrows by causing nest abandonment and decreased reproductive success. Habitat loss due to urbanization is another threat to Lincoln’s sparrows in Region 2. Rudzitis and Johansen (1989) have documented that those sparrow populations in counties that contain or are adjacent to federally designated wilderness areas grew two to three times faster than those in all other counties in the country beginning in the 1970s. Other threats to this species are the loss of habitat on breeding, migration, and wintering grounds; pesticide use in the winter range; mining; and collisions with television towers during migration. Lincoln’s sparrows should benefit from the regulation of livestock grazing in riparian wetlands and minimizing the impacts of recreation in riparian areas of subalpine zones, where the greatest breeding densities of Lincoln’s sparrows occur. Additionally, conservation of nesting habitat, migratory stop-over habitat, and wintering habitat should benefit the species. (text derived from SAP)
Loggerhead Shrike (Lanius ludovicianus)
The loggerhead shrike (Lanius ludovicianus) is a widespread species in North America, occurring in open habitats such as deserts, sagebrush, grasslands, and pastures. Recent contractions in its range and declines in abundance have occurred in many areas of North America and in several different habitat types. Despite a relatively intensive research and conservation effort in recent years, the factors responsible for the species’ near range-wide declines are not yet clear. Direct loss and degradation of native grassland and sagebrush habitats have been cited as primary factors in the decline of loggerhead shrikes. In addition, several recent studies have suggested that continuing loss and degradation of wintering habitats in the southern United States are primary causes of low overwinter survival among migratory populations of shrikes. In the western half of USDA Forest Service Region 2, livestock grazing may negatively affect loggerhead shrikes. In shrubsteppe and shortgrass habitats, livestock grazing may reduce local prey availability by reducing or altering vegetation composition and structure. Also, if livestock damage or kill thickets or trees, they may eliminate shrike nest sites. Further east, in areas of mixed- to tallgrass prairie, light grazing may improve foraging conditions by reducing grass density. (text derived from SAP)
McCowns Longspur (Calcarius mccownii)
McCown’s longspurs (Calcarius mccownii) are locally abundant breeding birds of the shortgrass prairies of the Great Plains. In Region 2 of the USDA Forest Service, they commonly breed only on the Pawnee National Grassland in Colorado and the Thunder Basin National Grassland in Wyoming. They winter mostly south of Region 2. Most populations appear to be stable or increasing, but due to a historical long-term decline in abundance on both their breeding and wintering grounds, this species is ranked by various state, federal, and private conservation organizations as a grassland “species of concernâ€, “high priorityâ€, “imperiledâ€, with “pressing needsâ€, “state imperiledâ€, or a species of “conservation concernâ€. Loss of native shortgrass prairie to agriculture and development on both breeding and wintering grounds is the greatest threat to McCown’s longspurs. Although most of the rangeland loss to agriculture was historical, more recent losses are not insignificant. In Colorado, for example, 3.8 percent of the remaining short and mixed-grass prairies east of the Rockies was lost to agriculture and urban expansion from 1982 to 1997 (Seidl et al. 2001). Habitat loss from increasing oil and gas development, especially in Wyoming, and the associated negative impacts of disturbance and fragmentation also pose a threat to McCown’s longspurs. Fire suppression, prairie dog control, increasing recreational activities, and the use of pesticides are somewhat lesser threats. Any absolute changes in survival, or proportional changes in first-year and adult survival, will have major impacts on the population dynamics of this species. (text derived from SAP)
Mountain Plover (Charadrius montanus)
The mountain plover (Charadrius montanus) is a local and declining bird throughout its range. It was proposed for listing under the Endangered Species Act by the U.S. Fish and Wildlife Service in 1999, but was withdrawn in 2003. The mountain plover is one of a small number of endemic Great Plains birds, and its status may be one indicator of the health of this ecosystem. Mountain plovers nest locally in the western Great Plains from Montana south to New Mexico, in Utah, and in Mexico, and they winter in a broad band from Texas west and north to the Central Valley of California. The mountain plover has an interesting life-history strategy that includes multiple clutches per pair, moderate fidelity to nesting sites, and relatively low adult annual survival. The current continental population is thought to number between 8,000 and 10,000 birds, and the best data available suggest they are experiencing a significant long-term decline. This decline may be the result of a loss of nesting habitat, habitat alterations due to the loss of primary grazers, and a possible reproductive sink created by plovers nesting on agricultural lands. Several threats, particularly the loss of nesting habitat and threats to prairie dogs, are the focus of broader conservation efforts in the Great Plains that will benefit the plover and a host of other species. The conservation of mountain plovers hinges on the protection of high quality nesting habitat, the conservation of prairie dogs, and the use of proactive plover management with fire, rotational grazing, and protection of known nesting sites. (text derived from SAP)
Northern Harrier (Circus cyaneus)
The northern harrier (Circus cyaneus) is considered globally “secure†by the Natural Heritage Program because of its wide distribution across North America. However, because of its low density and often nomadic behavior, assessing this species’ population status and evaluating trend data are difficult, even with large-scale and long-term monitoring programs such as the Breeding Bird Survey. Nevertheless, historic and recent evidence suggest that the number of breeding harriers has declined across the species’ range. USDA Forest Service Region 2 represents a segment of the core of this species’ breeding range, and Breeding Bird Survey data suggest that northern harrier populations in Region 2 states have exhibited long-term declines that substantially exceed national trends. Breeding northern harriers require large tracts (greater than 100 ha) of habitat. The greatest threats to northern harriers in Region 2 are loss of wetland and grassland habitats, and the effects of habitat fragmentation, primarily from agricultural production. Northern harriers nest and hunt in moderate to tall vegetation with dense litter cover. Agricultural activities that remove vegetation, such as grazing and mowing, can make habitat unsuitable or lower habitat quality, as well as destroy active nests. Habitat fragmentation also may reduce recruitment by causing higher nest predation rates and increased competition with other predators for their primary prey items. (text derived from SAP)
Northern Goshawk (Accipiter gentilis atricapillus)
The northern goshawk (Accipiter gentilis atricapillus; hereafter referred to as goshawk) has been proposed for listing several times under the Endangered Species Act and its status has been (and still is) the object of considerable litigation. It is currently not listed as a threatened species but is considered a sensitive species or a species of concern by most governmental agencies and non-governmental organizations within Region 2. Currently, there is no demographic evidence in North America (including Region 2) that the goshawk is declining. This lack of evidence can be interpreted in two ways: 1) the goshawk is not declining; or 2) it is declining but I don’t have sufficient information to detect the declines. In Region 2, there is clearly insufficient data to determine population status. However, within Region 2, Partners in Flight suggest the goshawk may be declining in the Central Rocky Mountain Physiographic Region, which occurs in the extreme northwest section of the region. The basis for this conclusion is unknown but is likely based on the threat of habitat alteration to the goshawk’s preferred breeding season habitat. The primary threat to goshawk populations is alteration of its preferred habitat from timber management practices. Biologists and land managers have raised concerns over destruction and modification of goshawk nesting, post-fledging, foraging, and wintering habitat. Although the goshawk uses a wide range of forest communities during the breeding season, it prefers mature and old-growth forest for nesting and hunting. Its winter habitat preferences in North America are poorly understood but the limited data from North America and Europe suggest the bird can use the same habitats year-round as well as non-forested habitats at lower elevations. Although there is some evidence goshawks are resilient to forest fragmentation and can re-establish when cleared areas are reforested, the thresholds for population persistence have not been identified. (text derived from SAP)
Pinyon Jay (Gymnorhinus cyanocephalus)
Pinyon jays (Gymnorhinus cyanocephalus) occur in low-elevation conifer woodlands (primarily pinyon-juniper) throughout much of the interior western United States. Although they have been closely studied in northern Arizona and central New Mexico, their ecology is virtually unstudied in other portions of their range. Pinyon jays are highly social, living year-round in flocks composed of groups of closely related individuals. In fall and winter, flocks may disperse widely in search of their principal food source, pine seeds. Pinyon jays and pinyon pine (Pinus edulis) have coevolved, with jays depending on pinyon pine seeds as their primary food source in fall and winter, and also acting as dispersal agents for the seeds. Due to perceived long-term population declines in some areas, pinyon jays are considered a Species of Conservation Concern by the U.S. Fish and Wildlife Service within the Southern Rockies/Colorado Plateau Bird Conservation Region. They are also on the National Audubon Society’s Watch List and the Partners in Flight National Watch List. There has been growing concern recently over the fate of pinyon jays in the southwestern states (including Colorado) given the ongoing, widespread die-off of pinyon pines in the region. Severe drought over several years appears to have induced water stress in pinyon pines, making them more susceptible to attack by pinyon engraver beetles (Ips confusus). Compounding the current Ips infestation is the fact that beetles typically attack older, more mature pinyon trees, which are the primary cone producers and thus a principal source of food for pinyon jays. During such infestations, large areas may be severely affected, with up to 90 percent mortality of the local pinyon pine population.. (text derived from SAP)
Purple Martin (Progne subis)
Purple martins (Progne subis) are classified as G5, or globally secure, by the Nature Conservancy, and aside from some areas where local populations have declined or are threatened (Pacific Northwest, Great Lakes), there does not appear to be any imminent threat to martin populations. The situation in the Rocky Mountains, however, is not easy to assess. Recent studies have confirmed widespread nesting in western Colorado, but with a total estimated population size of only 500 to 1000 individuals. Limited survey work in southern Wyoming in 2004 resulted in the discovery of at least one colony. This colony, located on the Medicine Bow National Forest, is the first known nesting in the state since the 1930s. Purple martins are relatively rare breeders in the Intermountain West, and local populations may thus be particularly susceptible to forest management practices that affect their primary breeding habitat, mature aspen (Populus spp.) stands. A lack of information on the ecology and life history of purple martins in mountainous areas hinders our ability to develop a regional conservation strategy. The preferred habitat of purple martins in the Rocky Mountains is mature aspen forest with nearby meadows and open water. Martins nest in cavities in live aspen trees, which are currently not heavily harvested on National Forest System lands. However, there is some indication that aspen recruitment is low, primarily due to a lack of disturbance. The general rule of fire suppression on public lands has likely had a negative impact on purple martins by reducing the generation of new (post-disturbance) aspen stands, and by allowing encroachment of conifers into the open habitats preferred by foraging martins. Another key habitat component for purple martins is meadows, especially those with areas of open water. Such habitats may be degraded by forest management practices (e.g., road-building, timber harvesting) that alter the quality and distribution of water. (text derived from SAP)
Pygmy Nuthatch (Sitta pygmaea)
Although pygmy nuthatch (Sitta pygmaea) populations appear to be stable range-wide, currently available data do not provide reliable information on the status or trend of populations in USDA Forest Service Rocky Mountain Region (Region 2). The species’ naturally patchy distribution, the inaccessibility of much of its habitat, and the road-based nature of the Breeding Bird Survey have collectively resulted in small sample sizes and a high degree of variability associated with pygmy nuthatch survey data in Region 2. Nevertheless, due to its association with unmanaged mature ponderosa pine (Pinus ponderosa) forests, a habitat type that has decreased substantially in recent years, the pygmy nuthatch is considered a management indicator species or species of local concern on numerous national forests within Region 2. Degradation of mature ponderosa pine forests through timber harvesting and fire suppression represents the primary threat to the health of pygmy nuthatch populations in Region 2. Both practices reduce pygmy nuthatch foraging, breeding, and roosting habitats directly by removing large live and dead trees, and indirectly by shifting forest structure from an open canopy comprised of few large trees to a closed canopy comprised of many small trees. Fire suppression and livestock grazing interact to form another important threat, an increased risk of stand-replacing wildfires that reduce habitat availability and quality. Because pygmy nuthatches roost communally, often in large numbers during the winter, roost cavity availability may be an important limiting factor. (text derived from SAP)
Ruffed Grouse (Bonasa umbellus)
Ruffed grouse (Bonasa umbellus) occur at low densities in mid-elevation forest habitats in northern and northwestern areas of the USDA Forest Service Rocky Mountain Region (Region 2). Although there are no quantitative indications of a long-term population decline, the population status of ruffed grouse is difficult to assess because these grouse are cryptically-colored and are prone to relatively large annual fluctuations in numbers. Consequently, fixed-area census projects such as the Breeding Bird Survey do not adequately sample for ruffed grouse. Historical references suggest that ruffed grouse were formerly much more common in the Black Hills than they are today.
Development of a conservation/management plan for ruffed grouse in Region 2 will be hampered by the difficulty in accurately assessing their local status and by a lack of information on reproductive success. Ruffed grouse are considered a Management Indicator Species on two Region 2 forests, as well as a Priority species within nearby state Partners in Flight bird conservation plans. However, no research programs on the conservation status of ruffed grouse are currently underway in the Rocky Mountain Region. (text derived from SAP)
Sage Sparrow (Amphispiza belli)
The sage sparrow (Amphispiza belli) is a sagebrush obligate that can be common in its sagebrush shrubsteppe habitat. This assessment focuses on the only subspecies found within Region 2 of the USDA Forest Service, A. b. nevadensis. Breeding Bird Survey data indicate a decline in sage sparrow populations between 1966 and 1991 throughout the western United States. Within Region 2, sage sparrow populations in the Wyoming Basin and Southern Rockies physiographic strata have exhibited long-term declines. The sage sparrow is listed as a priority species in the Colorado and Wyoming Partners in Flight bird conservation plans. Reported sage sparrow population declines are likely linked to extensive alteration of sagebrush (Artemisia spp.) shrubsteppe habitat on the species’ breeding grounds. Though widespread, this habitat constitutes one of the most endangered ecosystems in North America due to extensive, ecologically transformative influences of livestock grazing and, to a lesser degree, alteration of natural fire regimes and invasion by exotic plant species. Loss and fragmentation of habitat due to agricultural, urban, suburban, energy, and road development also threaten the species. (text derived from SAP)
Short-eared Owl (Asio flammeus)
Despite widespread concern over declines in their abundance in many areas of North America, short-eared owls (Asio flammeus) are classified as G5 (secure) by the Nature Conservancy. The population status of this species is difficult to assess because they are nomadic and prone to annual fluctuations in numbers. Consequently, fixed-area census projects such as the Breeding Bird Survey do not adequately sample for short-eared owls. Most recent regional ornithological summaries (including state and provincial bird atlas projects) suggest that declines have occurred across the species’ range, including many areas in Region 2. Short-eared owls appear particularly sensitive to habitat loss and fragmentation, as they require relatively large tracts of grassland and are ground nesters, making them susceptible to the increased predation pressure that is typical within fragmented habitats and near rural developments. The development of conservation/management plans for short-eared owls has been hampered by the difficulty in accurately assessing their local and regional status, and by a lack of information on reproductive success. Although they are listed as a Bird of Conservation Concern by the U.S. Fish and Wildlife Service, as well as a Priority species within many state and regional Partners in Flight bird conservation plans, no research programs on the conservation status of short-eared owls are currently underway. (text derived from SAP)
Trumpeter Swan (Cygnus buccinator)
The trumpeter swan (Cygnus buccinator) is classified as G4 (apparently secure) by the Natural Heritage Program because of its wide distribution across North America and its increasing population trends. In 2005, the North American population was estimated to contain 34,803 individuals. Abundant and widespread across most of North America prior to the 19th century, the trumpeter swan was nearly extirpated in the contiguous United States due to market-hunting. In response to range-wide conservation efforts, including protection from hunting, reintroductions, land acquisition, and wetland management, the three regionally-managed populations (Pacific, Rocky Mountain, Interior) have increased at a rate greater than 5 percent per year since range-wide surveys were implemented in 1968. Only the breeding flock in the Greater Yellowstone region has not increased; there, flock size has remained stable since 1968. The only flock that occurs within the USDA Forest Service’s (USFS) Rocky Mountain Region (Region 2) is the High Plains flock (formerly Lacreek), which was originally established in the Lacreek National Wildlife Refuge, South Dakota in the early 1960’s via reintroduction. This flock has expanded into western South Dakota, eastern Wyoming, and western Nebraska, has increased at a significant rate of 4.9 percent per year from 1968 to 2005, and currently numbers around 500 individuals.
The trumpeter swan is afforded a significant amount of attention by government agencies, private organizations, and individuals because of its striking plumage, large size, and iconic status. Management is directed by a national waterfowl management plan and three regional trumpeter swan management plans. On-the-ground management is typically conducted on a flock-by-flock basis. (text derived from SAP)
Wilson’s Warbler (Wilsonia pusilla pileolata)
Wilson’s warbler (Wilsonia pusilla pileolata) populations are reported to be stable to declining range-wide, and appear to be stable to increasing within U.S. Forest Service, Rocky Mountain Region. Loss of riparian habitats through dewatering, livestock grazing, and development and disturbance by recreation in riparian areas are the primary threats to Wilson’s warblers. Neotropical migrant songbirds, such as the Wilson’s warbler, represent a unique challenge for identifying threats and potential impacts to populations. In general, it is difficult to monitor songbird populations, and this is exacerbated in large portions of U.S. Forest Service, Rocky Mountain Region due to isolated mountainous habitat. Consequently, the population status of Wilson’s warblers is difficult to determine for this assessment. However, if impacts and future threats to important habitat areas are identified and mitigated, we believe positive responses for species such as the Wilson’s warbler will result within this region. (text derived from SAP)
Yellow-billed Loon (Gavia adamsii)
Northern Alaska breeding grounds support an average of 3,369 Yellow-billed Loons (Gavia adamsii), and about 780 more occur in western Alaska, making this species one of the least common regularly breeding birds in the mainland United States (Section 6–E). Because of its restricted range, small population size, specific habitat requirements, and the potential for oil development throughout its U.S. breeding range, the Yellow-billed Loon has been a Species of Management Concern, or Bird of Conservation Concern, to the U.S. Fish and Wildlife Service since 1995 (USFWS 1995, 2002a) and is the subject of a recent petition for listing under the Endangered Species Act (Center for Biological Diversity 2004).
The first part of this publication, the Status Assessment, provides a comprehensive and critical review of the published and unpublished data on Yellow-billed Loon population size, population trend, and potential threats to the population and its breeding and wintering habitat. The literature review relies heavily on that presented in North (1994), Barr (1997), and Fair (2002). The Status Assessment identifies gaps in our knowledge and in current monitoring programs. The last section of the publication, the Conservation Plan, details 7 objectives and 29 specific strategies to fill gaps identified in the Assessment. The format of the Status Assessment follows that suggested by the U.S. Fish and Wildlife Service (USFWS 2000). The preparation of this document was requested and funded by the Nongame Bird Office, Division of Migratory Birds, Region 7, U.S. Fish and Wildlife Service. This document is a compilation of biological data and a description of past, present, and potential future threats to the Yellow-billed Loon. (text derived from SAP)
American Oystercatcher (Haematopus palliatus)
The American Oystercatcher (Haematopus palliatus) is the most widely distributed of the four oystercatcher species in the Western Hemisphere. Its range covers almost the entire
Atlantic Coast from northeastern United States to southern Argentina; on the Pacific Coast it is found from northern Mexico to central Chile. The current plan covers the entire
range of the species, and is not intended to serve as a substitute or update for the conservation plan and business plan that cover the U.S. Atlantic and Gulf Coast populations. Readers are advised to refer to those plans, available at www.whsrn.org, for more detailed information about that population. The subspecific taxonomy of H. palliatus is far from clear, but five races are recognized in this plan, primarily to facilitate reference to specific populations (Figure 1). These are nominate H. p. palliatus (coasts of eastern and southern United States; eastern Mexico; Pacific and Caribbean coasts of Central America; the Caribbean; and northern and eastern South America); H. p. frazari (Gulf of California and western Mexico); H. p. pitanay (coast of western South America); H. p. durnfordi (coast of southeast South America) and H. p. galapagensis (Galapagos Islands). The Galapagos race may deserve species status. Based on a review of existing population estimates and an extrapolation of data from quantitative surveys throughout its range, revised estimates are given for the populations of all five subspecies, and a total population of about 43,000 individuals. The nominate race is the most abundant with an estimated population size of about 20,000 individuals, while the least abundant is H. p. galapagensis, with just 300 individuals estimated. (text derived from SAP)
Black Oystercatcher (Haematopus bachmani)
The Black Oystercatcher (Haematopus bachmani), a large, long-lived shorebird with a global population of roughly 10,000 individuals, is completely dependent upon marine shorelines
throughout its life cycle. Favoring rocky shorelines, Black Oystercatchers occur uncommonly along the North American Pacific coast from the Aleutian Islands to Baja California. They are most abundant in the northern portions of their range, from Alaska to southern British Columbia. Breeding oystercatchers are highly territorial and nesting densities are low; however, they tend to aggregate in groups of tens to hundreds during the winter months. They forage exclusively on intertidal macroinvertebrates (e.g., limpets and mussels) and are most commonly found near sheltered areas of high tidal variation that support abundant invertebrate communities. Foraging habitat is primarily low-sloping gravel or rock beaches where prey is abundant. The Black Oystercatcher is a keystone species along the North Pacific shoreline and is thought to be a particularly sensitive indicator of the overall health of the rocky intertidal community. Population estimates have been based mainly on incidental observations made during seabird surveys. More accurate estimates of population size and trends are needed to assess how oystercatchers are affected by limiting factors. Migratory movements of individuals in southern populations are thought to be short with individuals generally aggregating near their nesting areas; however, this is based on opportunistic observations at a small number of sites. Most individuals in northern populations migrate from nesting areas, but wintering locations and migratory routes remain largely unknown. Black Oystercatcher populations appear to be ultimately regulated by the availability of high quality nesting and foraging habitat. (text derived from SAP)
Buff-breasted Sandpiper (Tryngites subruficollis)
The Buff-breasted Sandpiper (Tryngites subruficollis) is a medium-size shorebird that breeds sporadically (both temporally and spatially) along Arctic coasts in Russia, Alaska, and Canada (Lanctot and Laredo 1994). It spends the nonbreeding (wintering) season in South America on the pampas of Argentina, Uruguay, and Brazil where individuals frequent heavily grazed grasslands adjacent to wetlands. Northbound migration proceeds through central South America, across the Gulf of Mexico, and through the central United States and Canada before the birds reach the Arctic coast. Southbound migration follows a similar route, but over a much broader front with juveniles frequently seen on the Atlantic coast of North America. Much smaller numbers of birds are also seen along the Pacific coast of North America and in Western Europe (mainly Ireland and England). Buff-breasted Sandpipers are unique among North American shorebirds in having a lek mating system. Males defend relatively small territories (e.g., males flying vertically next to each other in photo at right) that are used to attract females (see wing display in photo below) for mating, but provide no resources for raising offspring. Females select a mate then leave to nest and raise the chicks elsewhere (Pruett-Jones 1988, Lanctot and Weatherhead 1997; Lanctot et al. 1997, 1998). Once abundant, the population decreased substantially due to commercial harvests in the late 1800s and to loss of habitat along its migratory route in the central United States and its nonbreeding grounds in South America (Lanctot and Laredo 1994). The extreme approachability of the Buff-breasted Sandpiper and its tendency to return to a wounded flock member made this species especially vulnerable to mass shooting. Recent surveys on breeding, migration, and nonbreeding grounds suggest this species may still be declining, although more study is needed to accurately determine the actual population size and trend. (text derived from SAP)
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Hudsonian Godwit (Limosa haemastica)
The Hudsonian Godwit, Limosa haemastica, is the smallest and least well known of the four shorebird species in the genus Limosa. Major difficulties exist in studying Limosa haemastica, mainly because it spends much of the year in remote locations. The known nesting areas of the Hudsonian Godwit (hereafter, “godwit†refers to Hudsonian Godwits) occur in three disparate regions in the Nearctic: the Hudson and James Bay region of northeastern Canada; the Mackenzie and Anderson river deltas of northwestern Canada; and scattered pockets of appropriate habitat in southcentral and western Alaska. The Hudson and James bay populations, estimated at 36,000 individuals, are already at the target population level, while the Alaskan population, estimated at 14,000 individuals, should be increased by 25% according to the U.S. Shorebird Plan (Brown et al. 2001). Godwits are much more concentrated during the non-breeding season, when they gather in three main areas in southern South America: Bahia Lomas, Chile and Bahia San Sebastian, Argentina, both on the island of Tierra del Fuego, and Isla Chiloe and the adjacent mainland coast in central Chile. It is not entirely clear whether the three breeding populations also spend the boreal winter in different areas or if the different populations mix from year to year. It also is not known what routes the three groups follow between breeding and nonbreeding areas. Groups of godwits stage during the fall at areas to the south of their breeding grounds in Canada and Alaska, especially on the upper Cook Inlet in southcentral Alaska; the Quill Lakes and Luck Lake in Saskatchewan; and upper James Bay in Ontario. The godwits, generally, are not seen again in any numbers until they arrive in the very southernmost state of Brazil, Rio Grande do Sul, and northernmost provinces of Argentina, particularly Buenos Aires. Within the past few decades, however, observers have noted large groups of godwits using oxbow lakes along the upper Amazon, near Manaus, Brazil, thus presenting what may be an important stopover site midway between staging areas in southern Canada and better known stopover sites in southern South America. (text derived from SAP)
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Marbled Godwit (Limosa fedoa)
The Marbled Godwit (Limosa fedoa) nests primarily in temperate grasslands of northcentral United States (U.S.) and south-central Canada (i.e., mid-continental population) and winters primarily at coastal sites from central California south to central Sinaloa. There are also two small breeding populations that are highly disjunct from the mid-continental population— one on the Alaska Peninsula (L. f. beringiae) and one at James Bay in Ontario, Quebec, and Nunavut. Alaskan birds are thought to winter at coastal sites from Washington south to central California, and James Bay birds are believed to winter at coastal sites of the southeastern U.S. and/or at sites along the U.S. Gulf of Mexico coast. The Marbled Godwit warrants conservation planning for several reasons: (1) its estimated global population is relatively small (140,000-200,000 birds), (2) its population trends and ecology are poorly understood, and (3) significant habitat loss or degradation appears to be eroding much of its breeding and wintering ranges. Primary mid-continental nesting habitat is native grassland encompassing complexes of relatively unvegetated, shallow wetlands. In these habitats, godwits face a number of threats, the most significant of which is habitat loss/ degradation due to agricultural conversion. Currently, the greatest threats to the two disjunct breeding populations are their small sizes. At wintering and coastal migration stopover sites, the most significant threats are development, recreation-based human disturbance, mariculture, and invasions of exotic plants and aquatic invertebrates. Threats at inland migration stopovers vary regionally, but the primary threat is inadequate water supply, which threatens the habitats themselves and exacerbates contamination, invasions of exotic plants, and disease outbreaks. (text derived from SAP)
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Red Knot (Calidris canutus)
The population of the rufa subspecies of the Red Knot Calidris canutus, which breeds in the central Canadian arctic and mainly winters in Tierra del Fuego, has declined dramatically over the past twenty years. Previously estimated at 100,000-150,000, the population now numbers 18,000-33,000 (18,000 if just the Tierra del Fuego birds are rufa, more if the knots of uncertain subspecific status that winter in northern Brazil (7,500) or Florida (7,000) are also rufa). Counts show that the main Tierra del Fuego wintering population dropped from 67,546 in 1985 to 51,255 in 2000, 29,271 in 2002, 31,568 in 2004, but only 17,653 in 2005 and 17,211 in 2006. Demographic studies covering 1994-2002, showed that the population decline over that period was related to a drop in annual adult survival from 85% during 1994-1998 to 56% during 1999-2001. Population models showed that if adult survival remained low, rufa would go extinct within about ten years. After 2002, the population held up in 2003-2004, but plunged again by nearly 50% in 2005 increasing the likelihood of extinction within the next decade. Despite intensive studies, the reasons for the population decline and reduced adult survival are imperfectly known. During northward migration, most rufa stopover in Delaware Bay where they feed mainly on the eggs of horseshoe crabs (Limulus polyphemus) and lay down fat and protein reserves both to fuel the 3,000 kilometer flight to the arctic breeding grounds and ensure their survival after they arrive at a time when food availability is often low. The crucial importance of Delaware Bay is demonstrated by studies that show that lower weight knots in Delaware Bay have lower survival than heavier birds and that over 1998-2002 the proportion of birds there at the end of May that weighed more than the estimated departure mass of 180 grams declined by over 60%. This might be the result of the progressive failure of the food supply in Delaware Bay and/or a trend for birds to arrive there later and/or in poorer condition. In years when Red Knots experience both reduced food availability and there are late arrivals, the result may be an exacerbation of the effects of each of these deleterious factors. The main identified threat to the rufa population is the reduced availability of horseshoe crabs eggs in Delaware Bay arising from elevated harvest of adult crabs for bait in the conch and eel fishing industries. Since 1990, there has been a substantial decline in the crab population. (text derived from SAP)
Red-Necked Phalarope (Phalaropus lobatus)
Red-Necked Phalarope populations have declined precipitously during migration at traditional maritime sites like the Deer Island, New Brunswick, Canada, area, used by some 2 million individual phalaropes in the 1970s and early 80s. It is unclear what effect this decline may have had on the overall population of the species. Despite some evidence of local declines at breeding sites, there is insufficient information to determine the status of the population as a whole. Monitoring the population to determine its actual status is a critical component of ongoing conservation actions. The most likely cause of the disappearance of phalaropes from the Deer Island area is severely reduced abundance of the zooplankton species, Calanus finmarchicus, in surface waters during the time phalaropes migrate through the area. This local decline reflects a more widespread decline of the species over the Scotian Shelf and Gulf of Maine as shown by long term oceanographic data. The cause of the decline in Calanus finmarchicus is unclear at present. The species is characteristic of cooler North Atlantic waters and would be sensitive to increases in sea temperatures. Temperatures have increased along the eastern seaboard of the US over the past 100+ years. There is an urgent need to develop monitoring and research programs to determine the current status of Red-Necked Phalarope populations, and to track the trend in population size over time. This plan outlines critical steps in the development of these programs, and proposes specific actions that should be undertaken immediately. Further conservation efforts will likely be needed once these actions are completed. (text derived from SAP)
Sanderling (Calidris alba)
The Sanderling (Calidris alba) is a small shorebird that breeds in the high arctic and migrates to temperate, tropical, and south-temperate beaches. In North America, the Sanderling is classified as a Species of High Concern because of its significant population declines, widespread habitat loss, and the threats it faces during the nonbreeding seasons (migration and winter). The Sanderling has a circumpolar breeding distribution, however there is little morphological differentiation among breeding populations. In contrast, some differentiation of individuals occurs on the nonbreeding range. Only one race of Sanderling is recognized. This species uses three major migration flyways in the Americas: Pacific, Central, and Atlantic. The largest North American concentrations of Sanderlings occur during spring migration, where tens of thousands of birds gather on the mid-Atlantic coast (coastal beaches of Delaware Bay) and at shallow alkaline lakes in the Canadian Prairies (Saskatchewan). Other large spring concentrations also occur on the central coast of North Carolina (Dinsmore et al. 1998, Walters 1984); on outer coastal sandy beaches of central Oregon, and southern Washington (Myers et al. 1984b, 1984b); and in Alaska (Isleib 1979). Fall migration in North America is more protracted, extending from mid-July to late October (or November), with birds being generally less aggregated in space. However, some Sanderlings aggregate in Massachusetts (up to 17,000 individuals), New Jersey (8,000), Virginia (several sites with 17,000), Texas (8,400), and Washington (10,000) (International Shorebird Survey database). Otherwise, Sanderlings spread out during fall, moving through important sites along the Great Lakes shorelines and all along Pacific and Atlantic coastlines. During winter, Sanderlings are dispersed, and a pronounced site fidelity in most locations and territoriality by many individuals likely influence population structure. (text derived from SAP)
Western Sandpiper (Calidris mauri)
The Western Sandpiper (Calidris mauri) is a small shorebird species that nests in coastal areas of western Alaska and Siberia. Most Western Sandpipers spend the non-breeding season at Pacific coastal sites. The combination of a restricted breeding range and a broad non-breeding distribution means that some Western Sandpipers migrate much farther than others. Western Sandpipers are differential migrants; males spend the winter farther north than females, and juveniles are disproportionately represented on the northern and southern edges of the distribution. There is also a life history difference as a function of migratory distance. Western Sandpipers spending their juvenile non-breeding season in northern Mexico migrate northward in their first spring, but many juveniles in Panama remain on the non-breeding grounds until their second spring. Western Sandpipers use a substantial number of sites throughout their annual range, and some sites support very large numbers of birds. Major migratory sites include the Parte Alta de la BahÃa de Panama, coastal northwestern Mexico, San Francisco Bay in California, Grays Harbor in Washington, the Fraser River delta in British Columbia, and Kachemak Bay, the Stikine River delta and the Copper River delta in Alaska. During winter, the largest documented concentrations of Western Sandpipers occur in San Francisco Bay in California, Laguna Madre in Tamaulipas–Texas, Laguna Ojo de Liebre in Baja California, BahÃa Santa MarÃa and Ensenada Pabellones in Sinaloa, and Parte Alta de la BahÃa de Panama. Although some of the most important sites are protected, many other sites are on unprotected lands.. (text derived from SAP)
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Whimbrel (Numenius phaeopus)
The Whimbrel (Numenius phaeopus) in the Western Hemisphere has received relatively little attention from shorebird biologists in recent decades except for having been identified as a species of high conservation concern in regional and national shorebird conservation plans. The purpose of this plan is to provide an overview of our current state of knowledge concerning the population status of the Whimbrel in the Western Hemisphere, to identify important conservation sites for the species, to recommend and prioritize conservation, research, and management needs, and to facilitate networking between parties interested in Whimbrel conservation. The Whimbrel breeds in arctic, sub-arctic, and boreal regions around the globe. In the Western Hemisphere, breeding birds occur in Alaska, northwestern Canada, and west and south of Hudson Bay. During the nonbreeding season (boreal winter), Whimbrels occur throughout the coastal regions of Mexico and Central and South America, with smaller numbers along the Atlantic, Pacific, and Gulf of Mexico coasts of the United States. The subspecies of Whimbrel breeding in North America (Numenius phaeopushudsonicus) is generally thought to be comprised of two disjunct breeding populations that maintain separate migratory and wintering ranges: a western population in Alaska and northwestern Canada, and an eastern population west and south of Hudson Bay. Although recent evidence from satellite telemetry studies has highlighted the uncertainty behind this generalization, the two populations are still referred to as ‘western’ and ‘eastern’. The most recent population estimate for this subspecies is 66,000 individuals, including 26,000 from the western population and 40,000 from the eastern breeding population. We present alternative interpretations of survey data that suggest a range between 55,500 and 73,100 individuals as a population estimate. Population trend information for the subspecies is generally lacking, but limited information suggests possible declines of at least the eastern population in recent decades. (text derived from SAP)
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Dunlin (Calidris alpina)
The Dunlin (Calidris alpina) is one of the more abundant migratory shorebirds of the Northern Hemisphere, and has an almost circumpolar distribution of breeding populations. Unlike most other shorebirds, the Dunlin shows considerable phenotypic and genotypic variation over its range, with up to 11 subspecies recognized. Three subspecies are known to occur in North America: C. a. arcticola, C. a. pacifica, and C. a. hudsonia, with population estimates of 750,000, 550,000, and 225,000, respectively. Despite their large population estimates, the U.S. Shorebird Conservation Plan lists the Dunlin (C. a. arcticola and C. a. pacifica) as a Species of High Concern (Brown et al. 2001), while the Canadian Shorebird Conservation Plan considers it a Species of Moderate Concern with known or potential threats (Donaldson et al. 2000). The Dunlin warrants conservation planning due to 1) recent rates of habitat loss in the nonbreeding range where the species tends to aggregate; 2) gaps in knowledge regarding factors limiting the populations; 3) the species’ vulnerability to a variety of impacts, given its strong tendency to aggregate; and 4) inadequate monitoring data for determining population trends, coupled with suspected declines in parts of its range. C. a. arcticola breeds in northern Alaska (and possibly Canada), and spends the nonbreeding season distributed from Japan to the People’s Republic of China. C. a. pacifica breeds in coastal western Alaska, and its primary nonbreeding distribution is the Pacific coast from southern British Columbia, Canada, to northwestern Mexico. C. a. hudsonia breeds in northern Canada and spends the nonbreeding season commonly on the Atlantic and Gulf coasts from Massachusetts to Mexico. All three subspecies use similar habitats during migration and nonbreeding. Dunlin are common at estuarine mudflats, but they can move among a variety of available habitats, from freshwater to brackish wetlands. Dunlin also are found in coastal and adjacent agricultural habitats, and some individuals spend part or all of the season inland in freshwater wetlands and agricultural habitats. (text derived from SAP)
Wilson’s Phalarope (Phalaropus tricolor)
Wilson’s Phalarope (Phalaropus tricolor) is a medium-size shorebird best known for congregating in huge, post-breeding flocks at a few sites in North America and for its reversed sexual dimorphism, with females being more colorful than the males. Unlike the two other phalarope species [Red Phalarope (P. lobatus) and Red-necked Phalarope (P. fulicarius)], Wilson’s Phalarope is a temperate breeder (as opposed to having a holarctic breeding distribution) and does not winter at sea. The species is confined to the Americas where it breeds in central Canada and the United States and winters primarily on saline lakes in the Andes of South America and the Southern Cone lowlands. Despite being a relatively numerous species with a population estimated at 1.5 million individuals, Wilson’s Phalarope warrants conservation planning because the species is believed to have undergone a significant decline in the past, as a result of habitat conversion, from which it has not recovered. Nevertheless, this apparent decline is a controversial issue to some extent, as a wide consensus does not appear to exist regarding the significant decline in the species’s population. Currently, it is unclear whether the species’s population is increasing, declining, or stable. While its breeding range has considerably expanded in recent decades, the species no longer breeds at a number of former sites, and the population has not shown a marked increase in size despite the expansion in range. (text derived from SAP)