OverviewThe Endangered Species Act (ESA) of 1973  protects plants and animals that are listed by the federal government as "endangered" or "threatened."  Two sections, § 7 and § 9, are central.
ESA § 9 makes it unlawful for anyone to "take" a listed animal, and this includes significantly modifying its habitat.  This applies to private parties and private land; a landowner is not allowed to harm an endangered animal or its habitat on his property.
Section 7 applies not to private parties but to federal agencies, but it covers their issuing permits for private activities, such as § 404 permits issued by the Corps of Engineers to people who want to do construction work in waters or wetlands. Specifically, § 7 imposes an affirmative duty on federal agencies to ensure that their actions (including permitting) are not likely to jeopardize the continued existence of a listed species (plant or animal) or result in the destruction or modification of critical habitat. See 50 C.F.R. § 402.01(a). Both § 7 and § 9 allow "incidental" takes, but only with a permit.
The ESA is enforced by the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Services (NMFS).  In the Act, "Secretary" refers to the Secretary of Commerce, acting through the NMFS for marine species listed in 50 C.F.R. § 222.23(a) (endangered) and § 227.4 (threatened),  or to the Secretary of the Interior, acting through the U.S. Fish and Wildlife Service for other plants and animals (see 50 C.F.R. §§ 17.2(b), 402.01(b)). Also, the Secretary of Agriculture has some authority over the importing and exporting of plants.
The ESA has so much potential to affect private property that it provokes heated debate and, sometimes, alarming newspaper headlines. Three cases in particular have become famous. The first was the Tellico Dam, which was begun before the ESA was enacted in 1973. The project came to a halt when the Secretary of the Interior declared a small fish called the snail darter to be endangered. Its habitat was thought to be limited to the part of the Little Tennessee River that was to be inundated by the reservoir behind the dam. The case reached the Supreme Court, which concluded that the ESA required it to stop construction of the dam, even though $53 million had already been spent. Tennessee Valley Authority v. Hill , 437 U.S. 153 (1978). Eventually Congress directed  that the Tellico Dam be completed, and President Carter declined to veto the bill. Meanwhile populations of the snail darter had been transplanted  to other nearby rivers, and evidence of other natural populations of them had been discovered as well. The snail darter was upgraded to merely "threatened" in 1984.
The second famous case was the 1990 listing of the northern spotted owl as endangered, with the result that millions of acres of Pacific Northwest forests became protected habitat. See Robertson v. Seattle Audubon Society , 503 U.S. 429 (1992). The timber industry was alarmed at the loss of millions of acres of timberlands, labor unions worried about the loss of jobs, and homebuilding and real estate interests argued that there would be even wider economic harm. President Bush, campaigning for his second term as President, said "[i]t is time to make people more important than owls."
The third case was that of an immigrant who found that his farm near Bakersfield, California, was listed as habitat for the Tipton kangaroo rat and could not for that reason be plowed. He plowed anyway and was jailed, reportedly, for five months. In a related story, it was reported that restrictions on clearing brush in rat habitat had prevented firefighters from plowing a firebreak, causing more than a dozen houses to burn. The facts about these cases, however, were disputed, and it is hard to know where the truth lies.
The ESA retains its power to alarm people and business interests, especially when the economic costs are high and the species unglamorous. The statute, after all, protects insects such as the Delhi sands flower-loving fly and Hungerford's crawling water beetle as well as the bald eagle and grizzly bear. In August 1999 Colton, California, made the news because the Delhi Sands flower-loving fly was interfering with plans to develop an industrial park. Although the law contains some provisions for considering the economic cost of protecting plants and animals, Congress wrote the most important ESA provisions in sweeping and near absolute terms.  In the Tellico Dam case, the Supreme Court said that Congress had intended endangered species to be afforded the highest of priorities. 437 U.S. at 169.
Which Animals and Plants are "Threatened" or "Endangered"?The ESA protects only plants and animals that have been officially listed as "endangered" or "threatened." The procedures for listing a species are in § 4 of the ESA, 16 U.S.C. § 1533, and the regulations in 50 C.F.R. Part 424. The actual lists are in 50 C.F.R. Part 17.
An "endangered" species is one that is "in danger of extinction" throughout all or a significant portion of its range. 16 U.S.C. § 1532(6). A "threatened" species is one that is "likely to become endangered" within the foreseeable future. 16 U.S.C. § 1532(20).
Congress refined these definitions into five criteria, any one of which will justify listing: impacts to the species' habitat or range; overuse of the species by humans; disease or predators; inadequacy of existing legal protections; or "other natural or man-made factors" affecting the species' continued existence. 16 U.S.C. § 1533(a)(1). More detailed criteria for listing are in 50 C.F.R. § 424.14(b)(2). Importantly, the decision to list is made "without reference to possible economic or other impacts of such determination." 50 C.F.R. § 424.11(b). It is made solely on biological grounds, without consideration of economic or other issues.
The listing process starts either with nomination of a species by the Fish and Wildlife Service or the National Marine Fisheries Service or by a petition from anyone or any agency. 16 U.S.C. § 1533(b)(3)(A). How the FWS manages listing petitions is described at http://www.fws.gov/r9endspp/petman.html . Once the FWS or NMFS decides that a petition for listing is warranted, it undertakes a "status review" and within a year must decide to list the species, reject the proposal or petition, or give itself more time. 16 U.S.C. § 1533(b)(3)(B). If the agency rejects the petition, its decision is subject to court review. 16 U.S.C. § 1533(b)(3)(C)(ii).
If it decides to list the species, it must propose a rule under the informal rulemaking procedures of the Administrative Procedure Act. 16 U.S.C. § 1533(b)(4). After it publishes notice of the proposed rule in the Federal Register, the agency has one year to make a decision. Notice of the proposal is distributed to fish and wildlife experts and state and local governments, and a hearing must be held (if one is requested) within 45 days of publishing the proposed rule. 16 U.S.C. § 1533(b)(5)(E); 50 C.F.R. § 424.16(c)(3).
Because of "serious backlogs" of listing actions, FWS has proposed guidance for assigning relative priorities to them. 63 Fed. Reg. 10,931 (March 5, 1998). The guidance divides listing actions into Tiers 1, 2, and 3, with the highest priority being Tier 1, which is for listings under the emergency listing provision of § 4(b)(7) of the ESA for species that face a significant and imminent risk to their well-being.
When the agency determines that a species is endangered or threatened, it is also supposed to designate the species' "critical habitat" (16 U.S.C. § 1533(a)(3)). Critical habitat includes the areas within the geographic area occupied by the species on which are found physical or biological features "essential to the conservation of the species" and which may require special management considerations or protection. It also includes other specific areas, not presently occupied by the species, that are essential for its conservation; this means that a person's land might be designated critical habitat for an endangered kangaroo rat even if no such rat had ever been found on the property. The agency must use the "best scientific data available" to designate critical habitat (id. § 1533(b)(2)), but the economic impact must also be considered: an area can be excluded from "critical habitat" on a cost-benefit basis, unless excluding it would "result in the extinction of the species." Nevertheless, the Services often decline to examine economic impact when they designate critical habitat because, they argue, the impacts of critical habitat designation over and above the impacts of the listing itself are only "minimal." See 64 Fed. Reg. 5741 col. 2 (February 5, 1999) (proposed designation of critical habitat for steelhead in Washington, Oregon, Idaho, and California).
The lists of threatened and endangered wildlife and plants are 50 C.F.R. §§ 17.11 and 17.12. Critical habitats are found in 50 C.F.R. §§ 17.95 and 17.96 and 50 C.F.R. Part 226. The official FWS list is at http://www.fws.gov/r9endspp/vertdata.html . 
If a species recovers and gets out of danger, it can be delisted, after notice-and-comment rulemaking procedures. 16 U.S.C. § 1533(b)(3)(A); 50 C.F.R. § 424.11(d). A species may also be upgraded from endangered to merely threatened, 16 U.S.C. § 1533(a)(2)(B)(ii), although in practice there is little difference either to the species or to affected landowners. The bald eagle, to name the most famous example, was listed as endangered in 1978,  was reclassified as "threatened" in 1995, and may be delisted entirely by the end of 1999.
Listing decisions are subject to judicial review and can be overturned if, for example, the agency failed to articulate a rationale for the listing or failed to follow procedures. See Northern Spotted Owl (Strix Occidentalis Caurina) v. Hodel , 716 F. Supp. 479, 481 (W.D. Wash. 1988); Idaho Farm Bureau Federation v. Babbitt , 839 F. Supp. 739 (D. Ohio 1993).
"Candidate" species are species that FWS or NMFS is considering listing as endangered or threatened but which are not yet the subject of a proposed rule. From time to time FWS publishes a notice in the Federal Register listing "candidate or proposed" species. See, e.g. , 62 Fed. Reg. 49,397 (September 19, 1997). Candidate species are afforded no protection under the ESA, but § 4(b)(3)(C)(iii) of the Act requires the agencies to monitor the status of certain candidate taxa "to prevent their extinction while awaiting listing." See 58 Fed. Reg. 51,146 col. 2 (September 30, 1993). If a petition to list a species is warranted but listing is "precluded by other actions to revise the lists," the species is declared "warranted but precluded"; these require a new finding within a year.
Section 7 ConsultationESA § 7 regulates federal agencies, requiring them to ensure that their activities are "not likely to jeopardize" listed species or their habitats:
Each federal agency shall . . . ensure that any action authorized, funded, or carried out by such agency . . . is not likely to jeopardize the continued existence of any endangered species or threatened species or result in the destruction or adverse modification of habitat of such species . . . .
16 U.S.C. § 1536(a)(2). To make this decision, the federal agency "consults" with FWS or NMFS. The "consultation" process is described in 50 C.F.R. Part 402, and the federal agencies have published an Endangered Species Consultation Handbook. See 64 Fed. Reg. 31,285 (June 10, 1999).
Consultation has several steps.  First the agency asks the FWS (or NMFS) whether a protected species "may be present" in the area. If so, the agency prepares a "biological assessment" to determine the impact. (A biological assessment is mandatory, under 50 C.F.R. § 402.12(b)(1), for federal actions that are "major construction activities.") Next FWS reviews the information and prepares a "biological opinion" (16 U.S.C. § 1536(b)(3)(A)). If it finds the proposed action "not likely to jeopardize" the plant or animal (a "no jeopardy" opinion), it must specify the impact of any "incidental take" of the species, necessary mitigating measures, and conditions that should be imposed on the activity.
If the FWS or NMFS issues a "jeopardy" opinion, it must also propose reasonable and prudent alternatives that would not violate the ESA. 16 U.S.C. § 1536(d); 50 C.F.R. § 402.14(h)(3). The applicant then has several choices. He can take the "reasonable and prudent alternative" offered by FWS. 50 C.F.R. § 402.14(h)(3). He can appeal to the Endangered Species Committee, 16 U.S.C. § 1536(g), which is expensive and time-consuming. Or he can seek judicial review in federal court.
Section 9: "Take" of Endangered or Threatened SpeciesESA § 9 prohibits everyone, private person and federal agency alike, from "taking" endangered wildlife. The regulations extend this to threatened animals (see e.g. , 50 C.F.R. §§ 17.31, 17.21). "Take" includes "harming" a listed species,  and "harm" is defined by FWS regulation to include habitat alteration:
Harm in the definition of "take" in the Act means an act which actually kills or injures wildlife. Such act may include significant habitat modification or degradation where it actually kills or injures wildlife by significantly impacting essential behavioral patterns, including breeding, feeding, or sheltering.
50 C.F.R. § 17.3. See Babbitt v. Sweet Home Chapter of Communities for a Great Oregon , 515 U.S. 687 (1995). Section 11(b) of the ESA makes it a crime knowingly to "take" an endangered species without a permit or violate a regulation implementing the ESA. 16 U.S.C. § 1540(b)(1). You are permitted, however, to defend yourself of others from bodily harm. 16 U.S.C. § 1540(b)(3).
This prohibition against "take" covers fish and wildlife but not plants. Cf . 16 U.S.C. § 1532(8) and § 1532(14). It is, however, illegal to remove an endangered plant from federal land and reduce it to possession, and federal law also federalizes state law prohibitions on the taking of plants.
The Secretary may issue a permit for an "incidental take" of listed species that are incidental to and not for the purpose of a proposed activity (ESA § 10). Permits may be issued only after the landowner submits a "habitat conservation plan" (HCP), including proposed mitigation measures and an explanation of why alternatives were rejected. If FWS finds that the "take" will be incidental, will be satisfactorily mitigated, and will not appreciably reduce the species' chances for survival or recovery, it must issue the permit. There has been a move afoot recently to incorporate a "recovery" standard into HCPs, which would mean that HCPs would have to contribute affirmatively to the recovery of affected species, whereas under present law an HCP can be approved so long as it does not degrade the species further. HCPs can be very expensive to prepare and are especially burdensome for small businessmen and small landowners.
In 1996 the FWS and NMFS issued a joint Handbook for Habitat Conservation Planning and Incidental Take Permitting Process (HCP Handbook), which explains that HCPs may be processed under three models. 61 Fed. Reg. 63,854 (December 2, 1996); see also notice of draft addendum, 64 Fed. Reg. 11,485 (March 9, 1999). It created a "low-effect" HCP category for small landowners and other low-impact projects that have only minor or negligible effects on listed species or other environmental resources. A low-effect HCP is exempt from the National Environmental Policy Act (NEPA) and does not require an environmental assessment or environmental impact statement. "Moderate" HCPs require an environmental assessment, and "high-effect" ones require an environmental impact statement.
FWS's and NMFS's "no surprises" rule, 63 Fed. Reg. 8859 (February 23, 1998), allows an applicant for an incidental take permit to negotiate long-term assurances that no additional mitigation of impacts will be required, even if circumstances change. The rule provides some assurance that no additional land use restrictions or financial compensation will be required from the permit holder if unforeseen circumstances arise indicating that additional mitigation is necessary. It has been challenged in court by environmentalists.
In mid-1997 FWS and NMFS published a series of proposals having to do with their Safe Harbor Policy and Candidate Conservation Agreements.  The final version was published in June 1999. 64 Fed. Reg. 32,706, 32,717, 32,726 (June 17, 1999). Safe Harbor agreements are an attempt to soften the rule that no good deed goes unpunished. Landowners are often willing to manage their properties so as to improve habitat but may fear that if they are too successful and endangered animals colonize their land, they will then be prohibited from using the land in the future because of the § 9 "take" prohibition. In return for voluntarily undertaking land management activities that will provide a "net conservation benefit," the landowner receives assurances that he will be allowed to alter or modify the property even if the alteration will result in an incidental "take" that would return the species back to originally agreed-upon "baseline conditions." 62 Fed. Reg. 32,180 col. 1-2 (June 12, 1997).
Candidate Conservation Agreements, as their name suggests, apply to species that are not yet listed as threatened or endangered but are being considered for listing. They provide assurances that, if the covered species are eventually listed, the property owners or state or local land managing agencies will not be required to do more than the agreement calls for. 62 Fed. Reg. 32,183 col. 3 (June 12, 1997).
Other Regulations about Endangered and Threatened SpeciesDesignation as a threatened or endangered species has impacts that go beyond the Endangered Species Act, because the designation ripples through other federal statutes and regulations that impose special requirements for listed species. For example, no underground mining activity may be conducted if it is likely to jeopardize the continued existence of endangered or threatened species (30 C.F.R. § 817.97); a Corps of Engineers § 404 permit for depositing dredged or fill material will not be issued if the discharge would take or jeopardize threatened or endangered species (33 C.F.R. § 323.4(a)(ix)); solid waste disposal facilities or practices are not allowed to cause or contribute to the taking of an endangered or threatened species (40 C.F.R. § 257.3-2); and sewage sludge may not be placed where it is likely to adversely affect a threatened or endangered species (40 C.F.R. § 503.24).
In particular, the ESA affects regulation under the Clean Water Act. In early 1999 EPA, FWS, and NMFS published a draft Memorandum of Agreement regarding enhanced coordination under the Clean Water Act and the ESA. 64 Fed. Reg. 2741-57 (January 15, 1999). Moreover, EPA has been negotiating agreements with states that issue NPDES  permits for the discharge of water pollutants, requiring the states to take steps to enforce the ESA through their permit programs. In American Forest and Paper Association v. EPA , 137 F.3d 291 (5th Cir. 1998), however, the court held that EPA is not authorized to add any requirements for a state permitting program beyond the nine specific criteria in § 402(b) of the Clean Water Act and invalidated an endangered species coordination procedure involving the state of Louisiana. 
Science and the ESAObviously the ESA governs an area in which the law is greatly affected by science. See R. Taylor, Biological Uncertainty in the Endangered Species Act, 8 Nat'l Res. & Env. 6 (Summer 1993). In 1996 FWS and NMFS released three sets of scientific policy guidelines, namely a proposed rule on the treatment of intercrosses and intercross progeny, a proposed policy to establish consistency in controlled propagation (captive breeding) programs, and a notice of a policy to clarify the definition of "distinct population segments" for purposes of listing, delisting, or reclassifying species under the ESA. 61 Fed. Reg. 4710, 4716, 4722 (February 7, 1996). The intercross guidance, for example, addresses the question whether an animal or plant is protected if one of its parents was a listed species and the other parent was not.
Migratory Bird ActThe ESA is the best-known wildlife protection law, but there are others,  particularly the Migratory Bird Treaty Act, 16 U.S.C. §§ 703 - 711. This law forbids anyone to "hunt, take, capture, kill, . . . [or] possess" any bird protected by one of the treaties or to disturb their nesting sites. 16 U.S.C. § 703; 50 C.F.R. §§ 10.1, 10.12.
There are over 800 species of migratory birds, including many common ones like Canada geese, barn swallows, and two kinds of starling. See 50 C.F.R. § 10.13. Indeed, very few birds are not migratory for regulatory purposes. Courts have held that even the accidental killing of a migratory bird can be a criminal act under this law. See United States v. FMC Corp. , 572 F.2d 902 (2d Cir. 1978); United States v. Corbin Farm Service , 444 F. Supp. 510 (E.D. Cal.), aff'd , 578 F.2d 259 (9th Cir. 1978). Occasionally a businessperson will find that a flock of birds is interfering with her enterprise. Her inclination may be to put out some poisoned corn, but she does so at her peril.
The law also prohibits possessing any part of a migratory bird or its nest, egg, or product. See 50 C.F.R. § 10.12. Thus having a robin's egg or feather is a federal crime, though this is enforced only in commercial situations. Indian lore projects need to stick with turkey feathers, which are commercially available.
International TreatiesIn 1975 an international treaty called the Convention on International Trade in Endangered Species of Wildlife Fauna and Flora (CITES)  was signed by 118 countries, including the United States, and ratified by the U.S. Senate. Species and species products listed in Appendix I of CITES cannot be bought or sold for profit. For example, the African elephant was listed to restrict commerce in elephant ivory, which is why one sometimes sees ads for pocket knives with handles made of ivory from extinct mastodons. Species and species products listed in Appendix II to the treaty can be bought or sold only if the trade will not harm their survival.
The Wild Bird Conservation Act (WBCA) of 1992 focuses on bird species listed in the Appendices to CITES, 16 U.S.C. § 4901-4916. To import a bird you must meet certain requirements and obtain a permit as described in the Office of Management Authority's fact sheet "Wild Bird Conservation Act - Summary of Effects."  Regulations are in 50 C.F.R. Part 14.
The 1992 United Nations treaty on "biological diversity" might also affect wildlife. See 1992 United Nations Framework Convention on Biological Diversity, Internat'l Env. Rptr. 21:4001 (July 1992). However, the U.S. State Department has determined that the treaty will be implemented in the United States through existing legislation, such as the ESA. See Sen. Treaty Doc. 103-20, 103d Cong., 1st Sess. (November 20, 1993).
 Pub. L. 93-205, 87 Stat. 884, 16 U.S.C. § 1531 - 1534. The full text of the Act is at http://www4.law.cornell.edu/uscode/16/1531.html and http://www.fws.gov/r9endspp/esa.html . The ESA was preceded by the Lacey Act of 1900, the Bass Act of 1926, the Migratory Bird Act of 1918, the Endangered Species Preservation Act of 1966, and the Endangered Species Conservation Act of 1969. Amendments to the 1973 ESA were made in 1978, 1979, 1982, and 1988.Return to Text
 See 50 C.F.R. Part 17. The FWS endangered species home page is http://www.fws.gov/r9endspp/endspp.html#TOP . The NMFS site is http://www.nmfs.gov/prot_res/prot_res.html . An endangered species "ring" is http://www.mindspring.com/~blittle/odosbucket/endspecies.html . Fact sheets and news releases about threatened and endangered species, some of which may be a little dated, can be found at http://eelink.net/EndSpp.old.bak/factsheet.html , and a search for "endangered species" articles can be done at http://eelink.net/index.html . FWS policy documents are listed at http://www.fws.gov/r9endspp/poldocs.html . Government-sponsored propaganda for children may be found at http://www.fws.gov/r9endspp/kid_cor/kid_cor.htm . Additional Internet links are provided at http://www.fws.gov/r9endspp/sites.html . Return to Text
 It was settled that the ESA includes habitat protection by the 1995 U.S. Supreme Court decision Babbitt v. Sweet Home Chapter of Communities for a Great Oregon , 515 U.S. 687 (1995). Return to Text
 Division of authority is pursuant to the Reorganization Plan Numbered 4 of 1970. See 16 U.S.C. § 1532(15). The NMFS consolidated and reorganized its ESA regulations in March 1999. 64 Fed. Reg. 14,052 (March 23, 1999).Return to Text
 Examples of endangered marine species in 50 C.F.R. § 222.23 are the sockeye salmon, California steelhead, humpback whale, Hawaiian monk seal, and leatherback sea turtle. All the listed marine species are animals except for the threatened Johnson's seagrass, 50 C.F.R. § 227.4(p).Return to Text
 Public Law 96-69, 40 U.S.C. 174(b)-1 and 43 U.S.C. 377a, 93 Stat. 437, the Energy and Water Development Appropriations Act for fiscal year 1980, exempted the Tellico Dam from the Endangered Species Act and authorized completion of the project despite the threat to the snail darter.Return to Text
 An unofficial set of lists can be found at http://eelink.net/EndSpp.old.bak/ES.lists.html. A list of endangered species worldwide, not just in the United States, is at http://www.envirolink.org/species/onuses.html . Most states have their own state endangered species laws and their own lists of species based on state law, and there are many state-specific lists of endangered species on the Web. See http://www.fws.gov/r9endspp/stat%2Dreg.html .Return to Text
 FWS and NMFS have published an Endangered Species Consultation Handbook: Procedures for Conducting Consultation and Conference Activities under Section 7 of the Endangered Species Act. 64 Fed. Reg. 31,285 (June 10, 1999); http://www.fws.gov/r9endspp/section7/ section7.htm.Return to Text
 In full, the statutory definition of "take" includes "harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct" (ESA § 3(18)). See also 15 C.F.R. § 922.3, for marine animals, and 50 C.F.R. § 17.3, which defines "harass" as acts or omissions, whether intentional or negligent, that annoy wildlife so as to "significantly affect behavioral patterns."Return to Text
 FWS & NMFS Announcement of Draft Safe Harbor Policy, 62 Fed. Reg. 32,178 (June 12, 1997); FWS & NMFS Announcement of Draft Policy for Candidate Conservation Agreements, 62 Fed. Reg. 32,183 (June 12, 1997); FWS Safe Harbor Agreements and Candidate Conservation Agreements (proposed rule), 62 Fed. Reg. 32,189 (June 12, 1997).Return to Text
 Other federal wildlife protection laws to be aware of are the Lacey Act, 16 U.S.C. § 3372, which federalizes the violation of most state wildlife laws; the Marine Mammal Protection Act, 16 U.S.C. §§ 1361 - 1407; and the Bald Eagle Protection Act, 16 U.S.C. §§ 668 - 668d. There are at least 14 other federal statutes for the protection of plants and animals. See R. Little, Endangered and Other Protected Species , Chap. 14 (1992). This list of 14 includes the National Environmental Policy Act but not certain other important laws protecting fish such as § 316(a) and (b) of the Clean Water Act and the Magnuson-Stevens Fishery Conservation and Management Act, 16 U.S.C. §§ 1801-82; see also 50 C.F.R. Part 600. See also the "Digest of Federal Resource Laws of Interest to the U.S. Fish and Wildlife Service," http://www.fws.gov/laws/digest/reslaws/laws.html; "Fish and Wildlife Laws, Regs, Policies & Congressional Information," http://www.fws.gov/laws/index.html.Return to Text