C.F.R. » Title 50 » CHAPTER IV—JOINT REGULATIONS (UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR AND NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS › SUBCHAPTER A › PART 424—LISTING ENDANGERED AND THREATENED SPECIES AND DESIGNATING CRITICAL HABITAT › Subpart B—Revision of the Lists

50 C.F.R. § 424.11

Factors for listing, delisting, or reclassifying species

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(a) Any species or taxonomic group of species (e.g., genus, subgenus) as defined in § 424.02 is eligible for listing under the Act. A taxon of higher rank than species may be listed only if all included species are individually found to be endangered or threatened. In determining whether a particular taxon or population is a species for the purposes of the Act, the Secretary shall rely on standard taxonomic distinctions and the biological expertise of the Department and the scientific community concerning the relevant taxonomic group.

(b) The Secretary shall make any determination required by paragraphs (c), (d), and (e) of this section solely on the basis of the best available scientific and commercial information regarding a species' status without reference to possible economic or other impacts of such determination.

(c) A species shall be listed or reclassified if the Secretary determines, on the basis of the best scientific and commercial data available after conducting a review of the species' status, that the species meets the definition of an endangered species or a threatened species because of any one or a combination of the following factors:

(1) The present or threatened destruction, modification, or curtailment of its habitat or range;

(2) Overutilization for commercial, recreational, scientific, or educational purposes;

(3) Disease or predation;

(4) The inadequacy of existing regulatory mechanisms; or

(5) Other natural or manmade factors affecting its continued existence.

(d) In determining whether a species is a threatened species, the Services must analyze whether the species is likely to become an endangered species within the foreseeable future. The foreseeable future extends as far into the future as the Services can make reasonably reliable predictions about the threats to the species and the species' responses to those threats. The Services will describe the foreseeable future on a case-by-case basis, using the best available data and taking into account considerations such as the species' life-history characteristics, threat-projection timeframes, and environmental variability. The Services need not identify the foreseeable future in terms of a specific period of time.

(e) Species will be delisted if the Secretary determines, based on consideration of the factors and standards set forth in paragraph (c) of this section, that the best scientific and commercial data available substantiate that:

(1) The species is extinct;

(2) The species has recovered to the point at which it no longer meets the definition of an endangered species or a threatened species;

(3) New information that has become available since the original listing decision shows the listed entity does not meet the definition of an endangered species or a threatened species; or

(4) New information that has become available since the original listing decision shows the listed entity does not meet the definition of a species.

(f) The fact that a species of fish, wildlife, or plant is protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (see part 23 of this title) or a similar international agreement on such species, or has been identified as requiring protection from unrestricted commerce by any foreign nation, or to be in danger of extinction or likely to become so within the foreseeable future by any State agency or by any agency of a foreign nation that is responsible for the conservation of fish, wildlife, or plants, may constitute evidence that the species is endangered or threatened. The weight given such evidence will vary depending on the international agreement in question, the criteria pursuant to which the species is eligible for protection under such authorities, and the degree of protection afforded the species. The Secretary shall give consideration to any species protected under such an international agreement, or by any State or foreign nation, to determine whether the species is endangered or threatened.

(g) The Secretary shall take into account, in making determinations under paragraph (c) or (e) of this section, those efforts, if any, being made by any State or foreign nation, or any political subdivision of a State or foreign nation, to protect such species, whether by predator control, protection of habitat and food supply, or other conservation practices, within any area under its jurisdiction, or on the high seas.

[49 FR 38908, Oct. 1, 1984, as amended at 84 FR 45052, Aug. 27, 2019; 89 FR 24335, Apr. 5, 2024]
Notes of Decisions
Cited in 54 cases (4 in the last 5 years), 1995–2025 · leading case: Greater Yellowstone Coalition v. State of Wyoming, 665 F.3d 1015 (9th Cir. 2011).
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Greater Yellowstone Coalition v. State of Wyoming, 665 F.3d 1015 (9th Cir. 2011). · cites it 8× “§ 1533(a)(1); 50 C.F.R. § 424.11 (c). Listed species receive near-absolute legal protection against “taking,” which includes harassment, harm, hunting, killing, and significant habitat modification or degradation.”
Humane Soc'y of the United States v. Salazar, 76 F. Supp. 3d 69 (D.D.C. 2014). · cites it 11× “at 15,859 (citing 50 C.F.R. § 424.11 (d)) (emphasis added).”
Viva! Int'l Voice for Animals v. Adidas Promotional Retail Operations, Inc., 162 P.3d 569 (Cal. 2007). · cites it 3× “9, 1995); see 50 C.F.R. § 424.11 (d)(2) (2007) [authorizing delisting where a species has recovered].”
Am. Stewards of Liberty v. Dep't of the Interior, 370 F. Supp. 3d 711 (W.D. Tex. 2019). · cites it 4× “§ 1533 (a)(1) ; see also 50 C.F.R. § 424.11 (c), (d) (2014). Listing determinations must be made "solely on the basis of the best scientific and commercial data available.”
Defenders of Wildlife v. Salazar, 729 F. Supp. 2d 1207 (D. Mont. 2010). · cites it 4× “§ 1533(a)(1); 50 C.F.R. § 424.11 (d). The factors include: (A)the present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the…”
Defenders of Wildlife v. Sec'y, United States Dep't of the Interior, 354 F. Supp. 2d 1156 (D. Or. 2005). · cites it 4× “at § 1533(a)(1); 50 C.F.R. § 424.11 (c): The FWS shall make listing determinations “solely on the basis of the best scientific and commercial data available,” without reference to the possible economic or other impacts of such a determination.”
WildEarth Guardians v. Salazar, 741 F. Supp. 2d 89 (D.D.C. 2010). · cites it 4× “ary Judgment and DENY Defendant’s Cross-Motion for Summary Judgment with respect to Plaintiffs petition to reclassify the Utah prairie dog because (1) FWS failed to explain why the reduction in the species’ historical range did not indicate that reclassification may be warranted…”
Greater Yellowstone Coalition, Inc. v. Servheen, 672 F. Supp. 2d 1105 (D. Mont. 2009). · cites it 5× “§ 1533 (a)(1); 50 C.F.R. § 424.11 (d). The factors include: (A) the present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the…”
Humane Soc'y of the United States v. Kempthorne, 579 F. Supp. 2d 7 (D.D.C. 2008). · cites it 3× “§ 1533(a)(l)(A)-(E) (hereinafter the “listing factors” or the “Section 4(a)(1) factors”); see also 50 C.F.R. § 424.11 (c). The listing factors are: (1) present or threatened destruction, modification, or curtailment of a species’ habitat or range; (2) overutilization for…”
Tucson Herpetological Soc'y v. Salazar, 566 F.3d 870 (9th Cir. 2009). · cites it 2× “§ 1533 (a)(1); 50 C.F.R. § 424.11 (c). The Secretary must reach a listing determination "solely on the basis of the best scientific and commercial data available to him.”
Friends of Blackwater v. Kenneth Salazar, 691 F.3d 428 (D.C. Cir. 2012). · cites it 2× “25 The Secretary’s regulation on delisting, which provides that “[a] species may be delisted on the basis of recovery only if the best scientific and commercial data available indicate that it is no longer endangered or threatened,” 50 C.F.R. § 424.11 (d)(2) (1984) (promulgated…”
Ctr. for Native Ecosystems v. Cables, 509 F.3d 1310 (10th Cir. 2007). · cites it 2× “It asserts that agencies must insure that actions not only prevent the extinction of species but also allow for the recovery of the species, that is, allow the species to increase sufficiently in population that it can be removed from the list of endangered or threatened species…”
Show all 54 citing cases →
— 50 C.F.R. § 424.11(b) — 1 case
Sw. Ctr. for Biological Diversity Allison Rolfe, an Individual David Hogan, an Individual v. Bruce Babbitt, Sec'y of the Interior, 141 F.3d 1179 (9th Cir. 1998).
— 50 C.F.R. § 424.11(c) — 1 case
Ctr. for Native Ecosystems v. United States Fish & Wildlife Serv., 795 F. Supp. 2d 1199 (D. Colo. 2011).
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