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The goal of the ESA is the recovery of a listed species to population levels where protection under the Act is no longer necessary. A species may be classified as recovered if its decline has been halted or reversed, and threats minimized, so that its survival in the wild is likely. According to EWS, there are currently 11 species that have been delisted due to recovery. (See note on Rydberg milk-vetch.)
Brown pelican. The brown pelican (Pelecanus occidentalis) is a large coastal bird with a wingspan of nearly seven feet; it feeds almost exclusively on fishes captured by plunge diving. In the early 1960's, pelican populations suffered dramatic reductions as a result of organochlorine pesticide pollution. The pesticide endrin was thought to kill many pelicans through direct toxic effects, while the pesticide DDT led to eggshell thinning and reproductive failure. The brown pelican was listed under the ESCA as an endangered species throughout its U.S. and foreign ranges in 1970 (35 FR 16047 and 35 FR 8495). In 1973, the Environmental Protection Agency (EPA) banned the use of DDT in the United States (37 FR 13369) and began to sharply curtail the use of endrin. Since that time, pelican populations in the eastern Gulf and Atlantic coastal regions have reached or exceeded their historical breeding levels.
In 1985, the FWS removed the brown pelican from the endangered species list in Alabama, Florida, Georgia, South Carolina, North Carolina, and points northward along the Atlantic coast (50 PR 4938). The brown pelican remains endangered throughout the remainder of its range, which includes Mississippi, Louisiana, Texas, California, Mexico, Central and South America, and the West Indies.
Palau fantail flycatcher, Palau ground-dove, and Palau owl. The Palau Islands are located east of the Philippines in the South Pacific. They were formerly a U.S.-administered United Nations Trust Territory, and since 1994, have had an independent constitutional government. World War II fighting caused heavy damage to many of the islands, and as a result many populations of native species dramatically declined. The Palau fantail flycatcher (Rhipidura lepida), Palau ground-dove (Gallicolumba canifrons), and Palau owl (Pyrroglaux podargina) are three native bird species that were virtually eliminated during the war. These species were listed as endangered under the ESCA in 1970 (35 FR 8495) based on data from military surveys done shortly after the U.S. invasion of Angaur and Peleliu in 1944.
Since the end of World War II, the fantail flycatcher, ground-dove, and owl have returned to near original abundances and are not faced with any foreseeable threats. None of the species are sought as a game species, and the new constitution of Palau bans the personal possession of firearms, making it illegal to hunt with any type of gun. Based on this evidence, the FWS removed the Palau fantail flycatcher, the Palau ground-dove, and the Palau owl from the endangered species list in 1985(50 FR 37192).
American alligator. The American alligator (Alligator mississippiensis) is a large aquatic reptile that inhabits wetland areas of the southeast Atlantic and Gulf stares. It is one of only two species (Chinese alligator and American alligator) of the genus Alligator. Overharvesting due to commercial demand for alligator products led to significant population declines during the 1950's and 1960's. In 1967, the FWS listed the alligator as an endangered species under the ESPA. The Lacey Act Amendments of 1969 prohibited interstate commerce in illegally taken reptiles and their parts and products. The heavy penalties added under the ESA of 1973, and the listing in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) provided flirther protection against illegal taking. Populations have recovered and are now stable but disjunct, and limited to areas of remaining suitable habitat within their former range.
In 1977, the FWS downlisted the alligator from endangered to threatened in part of its range, including Florida and certain coastal areas of Georgia, South Carolina, Louisiana, and Texas (42 FR 2071). In 1987, the FWS downlisted the American alligator throughout the remainder of its range to "threatened due to similarity of appearance" (52 FR 21059). This classification reflects a complete recovery of the alligator, but is intended to facilitate necessary protections for the American crocodile (Crocodylus acutus) in the United States and foreign countries, and other endangered crocodilians in foreign countries, whose products are difficult to distinguish from those of the American alligator. Any proposed harvests under this classification must comply with the FWS's special rule on American alligators (50 CFR § 17.42(a)) and existing state statutes and regulations.
Rydberg milk-vetch. The Rydberg milk-vetch (Astragalus perianus) is a small, flowering plant that occurs in the mountain and plateau region of south central Utah. The FWS listed the milk-vetch as threatened in 1978 based on data showing that the plant was known to occur only in two locations: Bullion Canyon, Piute County, Utah, and Mt. Dutton, Garlield County, Utah (43 FR 17914). Beginning in 1983, the U.S. Forest Service conducted extensive surveys as part of a management plan developed for the Rydberg milk-vetch. The surveys resulted in the discovery of 11 additional populations with estimates of over 300,000 plants. Based on this new information, the FWS delisted the Rydberg milk-vetch in September 1989 (54 FR 37941).
The FWS has categorized this delisting as a "recovery" in its published list of species removed from the endangered and threatened lists. It should be noted, however, that the information published in the final rule delisting the Rydberg milkvetch could also be interpreted as an error in the original data.
Gray whale. Gray whales (Eschrichtius robustus) are large marine mammals that can reach lengths of 50 feet. They are bottom feeders whose main diet consists of small crustaceans called amphipods. The eastern North Pacific (California) population spends the summer feeding in the Bering, Chukchi, and Beaufort Seas. After migrating along the western shore of North America, gray whales spend the winter off of the coast of Baja California, where the young are born in shallow lagoons.
Commercial whaling significantly reduced gray whale populations, with estimates of 4,000 - 5,000 whales remaining by the mid 1800's. In 1947, the International Convention on the Regulation of Whaling banned the commercial harvesting of gray whales, although subsistence harvesting by aboriginal groups was allowed to continue. Since the ban, the eastern population has recovered to nearly the estimated original level, and is now neither in danger of extinction, nor "likely to become endangered within the foreseeable future throughout all or a significant portion of its range." The FWS concurred with the National Marine Fisheries Service's determination, and delisted the eastern North Pacific (California) population of the gray whale in 1994 (59 FR 3 094). The western North Pacific (Korea) population remains listed as endangered. Gray whales continue to receive protection under the Marine Mammal Protection Act of 1972 (16 U.S.C. § 1361).
Arctic peregrine falcon. The peregrine falcon is a medium-sized brown or blue-gray raptor that preys primarily on birds. Three subspecies of peregrines occur in North America arctic peregrine falcon (Falco peregrinus tundrius); American peregrine falcon (F p. anatum); and Peale's peregrine falcon (P. p. pealei). Arctic peregrines nest in the tundra regions of Alaska, Canada, and Greenland. They are highly migratory, wintering mostly in Latin America.
Arctic peregrine falcon populations declined in the 1950's and 1960's as a result of contamination with organochlorine pesticides such as DDT. These pesticides can accumulate to lethal levels in the fatty tissues of animals eating contaminated prey. At lower concentrations the principal metabolite of DDT can disrupt eggshell formation, causing eggs break easily.
Arctic peregrines were protected in 1970 under the ESCA, and subsequently covered in 1973 under the ESA. Populations began to recover when Canada restricted the use of DDT in 1970, followed by an EPA ban on DDT in the United States in 1973 (37 FR 13369). The United States restricted the use of other organochlorine pesticides, including aldrin and dieldrin, in 1974. The FWS downlisted the arctic peregrine falcon from endangered to threatened in March 1984 (49 FR 10520), and removed it from the list of threatened species in October 1994 (59 FR 50796). Arctic peregrines are still protected under the similarity of appearance provision of the ESA listing all Falco peregrinus found in the wild in the contiguous 48 states as endangered. Arctic peregrines also continue to be protected under the Migratory Bird Treaty Act (16 U.S.C.§703-712).
Red kangaroo, western gray kangaroo, eastern gray kangaroo. Kangaroos are large marsupial mammals indigenous to Australia. Marsupial populations in Australia began to decline with European settlement and the expansion of sheep ranching. A dramatic drop in kangaroo populations resulted from the development of a commercial market in kangaroo hides and meat. Citing evidence of excessive commercial utilization, the FWS listed the red kangaroo (Macropus rufus), eastern gray kangaroo (Macropus giganteus), and western gray kangaroo (Macropus fuliginosus) as threatened species in December 1974, and banned the commercial importation of kangaroos, their parts, and products (39 FR 44990). The FWS also asserted that Australia's regulatory control of hunting and trade were inadequate.
In April 1981, the EWS lifted the importation ban on the three threatened kangaroos after accepting the management programs of four Australian states. The FWS determining that managed "taking" would not be detrimental to the survival of the species, and removed the red kangaroo, eastern gray kangaroo and western gray kangaroo from the list of threatened wildlife in 1995 (60 FR 12888). A subspecies of eastern gray kangaroo (M. g. tasmaniensis) which occurs solely in Tasmania, retains its endangered classification under the ESA.
Information collected after a species has been listed as endangered or threatened may show that the data used for listing, or the interpretation of such data, were incomplete, erroneous or affected by later amendment of the ESA. The FWS deteimined that it listed eight species based on data that were incomplete or in error. (See note on Rydberg milk-vetch.) These delistings were the result of: (1) better data, including foreign scientific and commercial information; (2) scientific or taxonomic revision; and (3) discovery of previously unknown populations or habitats. (See http://www.fws.gov/~r9endspp/delisted.pdf for more information.) The FWS listed one species based on data that, as a result of subsequent amendment to the ESA, were determined to no longer be valid criteria for listing.
Mexican duck. The Mexican duck (once classified as Anas diazi) was historically found in Arizona, New Mexico, Texas, and throughout northern Mexico. This species was listed as endangered in 1967 under the ESPA based on evidence of habitat loss and declining populations due to hybridization with the common mallard duck (A. platyrhynchos). The Mexican duck was later determined to be a subspecies of A. platyrhynchos, and according to the FWS, "the interbreeding of two subspecies of the same species is an expected natural phenomenon. Protection under the definition of 'species' in the Act for one phenotype [an organism's general appearance] in a geographic segment or population of the same species is not permissible." (43 FR 32258) In short, the Mexican duck no longer qualified as sufficiently distinct under the ESA's definition of a species to warrant protection. Moreover, the loss of natural habitat was determined to no longer be a threat, because the species was found to be able to live in newly created agricultural areas. In 1978, the FWS removed the Mexican duck from the endangered species list (43 FR 32258).
Pine Barrens treefrog. The Pine Barrens treefrog (Hyla andersonii) is a small amphibian that occurs in New Jersey, the Carolinas, and Florida. In 1977, the Florida population only was listed as endangered under the ESA based on "the present or threatened destruction, modification, or curtailment of its habitat or range." Surveys at that time showed that there were only seven small breeding sites in Okaloosa County, with less than 500 estimated individuals. Surveys started in 1978 by the Florida Game and Fresh Water Fish Commission found more than 150 additional sites in Okaloosa, Walton, Santa Rosa, and Holmes Counties in Florida, and six sites in Escambia and Covington Counties, Alabama. Based on this new evidence, the FWS delisted the Pine Barrens treefiog in 1983 (48 FR 52740).
Indian flap-sheIled turtle. The Indian flap-shelled turtle (Lissemys punctata punctata) is a soffshell turtle occurring in southern and central India and Sri Lanka. A closely related turtle, L. p. andersoni, occurs in northern India, Pakistan, Nepal, Bangladesh, and Burma. The flap-shelled turtle was placed on Appendix I of CITES in 1975 at the request of Bangladesh. However, L. p. punctata was the taxa listed, not L. p. andersoni. Under a broad rule placing 159 taxa from Appendix I of CITES on the ESA's List of Endangered and Threatened Wildlife, the FWS ]isted L. p. punctata as endangered in 1976 (41 FR 24062). Although L. p. punctata was the subspecies listed by the EWS, its stated range included regions from which L. p. andersoni, not L.. p. punctata, is known to occur. It is unclear which subspecies - L. . p. punclata or L. p. andersoni, or both -- was meant to be induded in the CITES and ESA listings.
Subsequent reviews of the literature and available data could find no evidence to support this endangered status. To the contrary, scientists now classify L. p. punctata and L. p. andersoni as only one subspecies. This subspecies is the most common aquatic turtle in India. Consequently, the FWS removed the Indian flap-shelled turtle from the endangered species list in 1983 (48 FR 52740). This action did not affect the turtle's status on Appendix I of CITES.
Bahama swallowtail butterfly. The Bahama swallowtail butterfly (Heraclides (Papilio) andraemon bonhotei) is a tropical insect whose occurrence in Florida represents the northern limit of its distribution. This dark brown and yellow butterfly is restricted to tropical upland hardwood habitat, now found in the United States primarily in the Florida Keys. It was listed as threatened under the ESA in 1976 (41 FR 17736), at which time it was found only in Dade and Monroe Counties, Florida. The Bahama swallowtail was later found to be only a sporadic resident of the United States, and not distinct from the Bahamian population of the same subspecies. Moreover, the 1978 Amendments to the ESA limited protection at the population level to vertebrates (ESA, §3(15)). As a result ofESA amendment, the FWS took the Bahama swallowtail butterfly off the endangered species list in 1984 (49 FR 34501), since it was neither a vertebrate nor a distinct population.
Purple-spined hedgehog cactus. The purple-spined hedgehog cactus (Echinocereus engelmannii var. purpureus) was first described as a distinct taxonomic group in 1969 from specimens collected near St. George, Utah. It was determined to be very rare and was listed as endangered under the ESA in 1979 (44 FR 58866). Subsequent investigations found that the purple-spined hedgehog cactus is simply a dark-colored, short-spined phase that occurs interspersed throughout populations of E.e chrysocentrus; the two types of plants cross-pollinate readily in nature. Since E. e. chrysocentrus is common and widely distributed in the Mojave Desert of Arizona, California, Nevada, and Utah, in 1989, the FWS delisted the purple-spined hedgehog cactus (54 FR 48749).
Tumamoc globeberry. The Tumamoc globeberry (Tumamoca macdougalii) is a perennial vine in the gourd family with small greenish-yellow flowers and bright red fruits. It occurs from south central Arizona south through southern Sonora, Mexico. The FWS listed the globeberry as endangered under the ESA in 1986 based on the known presence of only 30 isolated populations in Pima County, Arizona, and five populations in Sonora, Mexico (51 FR 15906). In 1988 and 1989, the Bureau of Reclamation conducted surveys required by § 7 of the ESA to determine the impact of a Central Arizona Project canal and pipeline on the globeberry. These surveys determined that the species occurred across a more extensive range and was less habitat-specific than previously thought. Finding few threats of extinction in its newly identified habitat, the FWS removed the Tumamoc globeberry from the endangered species list in 1993 (58 FR 33562).
Spineless hedgehog cactus Botanist Karl Schuman first described the spineless hedgehog cactus (Echinocereus triglochidiatus var. inermis) in 1896 from specimens collected in southeast Utah and southwest Colorado. The FWS listed this subspecies as endangered in 1979 under the ESA based on its rare occurrence (44 FR 64744). The recovery plan for the spineless hedgehog cactus noted a question of its true taxonomic status, and later studies determined that it is simply a spineless form of the red-flowered hedgehog cactus (E. t. var.melanacanthus) that is widely distributed from northern Colorado and Utah to Durango and San Luis Potosi, Mexico. Finding that the spineless hedgehog cactus is "not a discrete and valid taxonomic entity and does not meet the definition of a species (which includes subspecies)," the FWS removed it from the endangered species list in 1993 (58 FR 49242).
McKittrick pennyroyal. The MeKittrick pennyroyal (Hedeoma apiculatum) is a perennial herb, four to six inches tall, with dense leaves and showy pink flowers. The species is endemic to the Guadalupe Mountains in northwest Texas and southeast New Mexico, where it occurs above 5,400 feet in limestone outcrops. The FWS described this pennyroyal as having "limited distribution, low numbers, and low reproductive potential" when it listed it as threatened under the ESA in 1982 (47 FR 30440). Subsequent surveys found this herb to be more widespread and abundant, and less vulnerable to human disturbance than previously thought. In 1993, the FWS took the McKittrick pennyroyal off the threatened species list (58 FR 49245).
Cuneate bidens. The cuneate bidens (Bidens cuneala) is an herb of the thistle family with yeUow flowers. It was first described in 1920 from specimens collected on the Hawaiian island of Oahu. The plant was listed as endangered in 1984 based on surveys indicating its rare occurrence (49 FR 6099). A recent revision of the Hawaiian members of the Bide us genus determined that B. cuneala is an outlying population of B. inolokalejisis that is common along the windward cliffs of nearby Molokai island. These new data indicated that cuneate bidens is "not a discrete taxonomic entity," resulting in the FWS delisting B. cuneata in 1996 (61 FR 4372).
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