A common theme in controversies over the Endangered Species Act (ESA) is that a conflict is triggered by the need for the same dwindling resources by humans and a listed species. The parties to the debate often have struggled for years over the basic allocation of those resources, from the Tellico River, to prairie grasslands, to the California Delta. The debate over ESA and species protection typically signals an intensification of an underlying and usually much larger struggle. Sagebrush habitat in the West is diminishing and becoming fragmented due to urbanization, global climate change, roads, fences, grazing, energy development, water scarcity, power lines, etc. While the remaining habitat is vast, its fragmentation presents special problems, especially for sage grouse, which need large treeless areas to discourage the roosting of additional avian predators. Thus, fences, roads, and utility poles can produce a very substantial change in the sagebrush habitat, even though the actual surface disturbance is minimal. Loss of habitat is the most common factor leading to species' decline. The story of listing the sage grouse under the ESA is a tale of petitions, missed deadlines, and lawsuits. Petitions have been filed under the ESA to protect the Gunnison grouse, the greater sage grouse, a western subspecies of the greater sage grouse, the Bi-State population, and the Columbia River Basin population. To date, no member of this genus has been listed at any taxonomic level. However, on January 11, 2013, the Fish and Wildlife Service (FWS or Service) proposed listing the Gunnison grouse as endangered. In a court settlement, FWS agreed to decide whether to list the Bi-State population by the end of FY2013 and the Columbia sage grouse population and the greater sage grouse by the end of FY2015. The ESA is intended to protect plants and animals from becoming extinct. It authorizes creating a list of protected species, either endangered (defined as being in danger of extinction) or threatened (defined as likely to become endangered in the foreseeable future). The ESA also prohibits taking these species, with limited exceptions. In addition, federal agencies are prohibited from destroying or adversely modifying their designated critical habitats. FWS is the federal agency that manages most species under the ESA. (The National Marine Fisheries Service (NMFS) supervises most marine mammals and oceanic species.) The Secretary of the Interior, acting through FWS (or the Secretary of Commerce, through NMFS, where relevant), is charged with the decision of whether to list a species. The listing decision is based on five criteria: habitat loss, over-harvesting, disease, inadequacy of existing regulatory protection, and other factors affecting its existence. In making the determination, FWS is charged with relying "solely on the basis of the best scientific and commercial data available." FWS may list a species independently, or citizens may petition the agency to make a listing. When a petition is filed, certain deadlines are imposed by statute. FWS must determine and publish a decision in the Federal Register within 90 days of the filing of the petition on whether the petition presents substantial evidence in support of a listing. Within 12 months of filing the petition, FWS must publish whether listing is warranted or not. A final decision must be made one year after the 12-month notice. FWS receives more petitions than it has resources to address, and has the option of publishing a determination at the time of a 12-month finding that a listing is "warranted but precluded" due to limited FWS resources. Failure to meet the deadlines can be a basis for suit. In addition to listing entire species, the ESA authorizes listing distinct population segments (DPS) of vertebrates. This term refers to a portion of a listed species separated from the rest of the species by genetic distinction and range. According to FWS policy established in 1996, in order to be designated a DPS, a population must be discrete (separated as a consequence of physical, physiological, ecological, or behavioral factors) and significant (meaning its demise would be an important loss of genetic diversity). Under the ESA, the species for which a warranted but precluded determination has been made are listed and ranked based on their priority for listing. The list, known as a candidate notice of review, is issued annually, with the Service reviewing those species' status. Each species is given a listing priority number (LPN) indicating how FWS has ranked the importance of listing to the survival of that species, subspecies, or DPS, ranging from one to 12. The lower the number, the higher the priority that species has. The Service works to resolve listing on candidates with the lowest numbers first. The ESA does not restrict activities affecting species for which a warranted but precluded determination is made, such as would occur if the sage grouse were found to be threatened or endangered. However, the species' status as a candidate could mean federal agencies will pay greater attention to its conservation. In the late 1990s, FWS developed a program to encourage nonfederal landowners to take conservation measures to protect species at risk. The Candidate Conservation Agreement with Assurances (CCAA) policy was designed to encourage nonfederal landowners (including state and local governments) to manage their property in ways that helped vulnerable species before they became listed under the ESA. According to FWS, the policy was motivated by the practice of property owners doing things to keep certain species from their land so that if that species became listed later, their property would not be subject to any associated restrictions. A CCAA rewards land management practices that aid species by assuring cooperating landowners that changes in federal policy would not impose additional burdens on them. The Service said, "the ultimate goal of Candidate Conservation Agreements with Assurances is to remove enough threats to the covered species to preclude any need to list them," but to do this, the substantive requirements of the CCAA must be performed by a significant fraction of the landowners in a species' range, and must provide noticeable improvement. In exchange for landowners' agreements to manage property for the benefit of a species, FWS issues assurances in the form of incidental take permits, excusing landowners from prosecution if their actions should take a listed species in the course of an otherwise lawful action. This permit can include species not currently listed, so that if they are listed later, the landowner would not face liability. The sage grouse ( C. urophasianus ) is the largest North American grouse: males weigh up to 7 pounds, and females up to 5 pounds. It is a squat, feathered, chicken-like bird, grayish with a black belly and spiky tail feathers, and highly prized by hunters. Its winter diet of sage leaves gives the flesh a strong sage flavor. It remains a game bird in many western states. Sage grouse have one of the lowest reproductive rates of any North American game bird. Because of this, "its populations are not able to recover from low numbers as quickly as many other upland game bird species." During winter snows, grouse shelter under sagebrush. Sage grouse feed on sage leaves throughout the year, but particularly in winter. They also eat leaves, flowers, and seeds from other plants, plus insects. Young grouse are dependent on insects for rapid growth. Male grouse of both species gather in the spring year after year in the same areas, called leks . The leks are found in open sagebrush areas, usually on broad ridges or valley floors where visibility is excellent and noise will travel well. There, the males strut, raise and lower their wings, fan their tail feathers, and make loud booming noises with the aid of bright yellow inflatable air sacs in their necks. Under optimal conditions, these sounds carry for hundreds of yards. Dozens or even hundreds of these males attract the attention of resident females, who survey the spectacular offerings of the displaying males, make their choices, and mate. Once mating has occurred, females leave the lek to nest, sometimes at a distance of several miles. Females raise their offspring alone, without help from males. The sage grouse is particularly vulnerable to changes in its habitat. Grazing, oil and gas development, communication towers, roads, utility poles, and wind turbines all pose a threat to sage grouse habitat. The roads provide ingress for invasive species such as cheatgrass; the fences interrupt migration to and from leks; and both fences and power lines provide perches for avian predators. While the grouse can fly, they do not fly long distances. They escape their predators through concealment, short flights to cover, or running under rocky outcrops or brush. Sage grouse are subject to predation by hawks, and avoid areas near tall objects that afford hawks a perch from which they can easily swoop down to attack an unwary bird. Cheatgrass is the primary invasive species threat to sagebrush habitat. It appears after an area has been grazed or when roads are developed. The nonnative grass spreads quickly, is disliked as forage by grazing mammals and grouse, and burns much more readily than native plants. Both the number of fires and the total area burned in sage grouse habitat have increased dramatically in the last decade when compared to the past 100 years. Drought and global climate change could accelerate the loss of sagebrush by facilitating cheatgrass invasion, increasing the likelihood and severity of fires. Additionally, many types of development introduce standing pools of water into an environment where none had existed. Coal bed methane production and oil wells both involve a footprint with a pond of some sort. This introduces mosquitoes into the habitat, and mosquitoes can carry the West Nile Virus.