Government Review Confirms Red Knot and Other Imperiled Bird Candidates Should Be Listed as Endangered Species

Red Knot at Delaware Bay. Photo: Mike Parr

The U.S. Fish and Wildlife Service (FWS) has released its revised list of species that are candidates for listing under the Endangered Species Act (ESA). Designation as a candidate species is not a requirement for listing under the ESA, and FWS can, and regularly does, list animals and plants without first placing them on the Candidate List. As a result, the Candidate List is regarded by many conservationists as a stall tactic by FWS.

Candidate species are assigned a listing priority from 1 to 12 based on the magnitude of threats they face, the immediacy of the threats, and their taxonomic uniqueness (for example, full species have higher priority than subspecies). The species’ listing priority dictates the relative order in which proposed listing rules are prepared, with the species at greatest risk (listing priority 1 through 3) being proposed first. Significantly, in the 2008 list, FWS determined that the ranking for the Red Knot should be raised from 6 to 3.

The rufa Red Knot, a reddish-brown shorebird slightly larger than an American Robin, migrates annually from Tierra del Fuego to its arctic breeding grounds, stopping to rebuild critical energy reserves by feasting on horseshoe crab eggs in Delaware Bay.

Only 14,800 Red Knots were counted in 2007 at the species’ primary wintering areas, a 15% decline from 2006, and a 75% decline from 1985. The results of several scientific studies have shown that a major reason behind this decline is a fall in the number of available horseshoe crab eggs due to overfishing of the crabs themselves, which are used as bait in conch and eel fisheries. This led FWS to conclude in their candidate review that, “The primary factor threatening the Red Knot is destruction and modification of its habitat, particularly the reduction in key food resources resulting from reductions in horseshoe crabs…”

“The U.S. Fish and Wildlife Service has once again confirmed that the Red Knot is increasingly threatened with extinction and deserving of heightened conservation measures, particularly immediate reductions in the commercial harvest of horseshoe crabs, whose eggs comprise the knot’s primary food source,” said Darin Schroeder, American Bird Conservancy’s Vice President of Conservation Advocacy.

The increased priority ranking for the species from 6 to 3 may speed its listing, but this could still be years off. “Too often species languish on the candidate species list and are not afforded the protections of the Endangered Species Act that we know work very well,” said Schroeder. “We urge the incoming administration to expeditiously act to list the species as the scientific research warrants.”

Other birds on the 2008 candidate list include:

• The Streaked Horned Lark inhabits Oregon and Washington and has a population estimated at approximately 730 birds. Its prairie breeding habitat has been nearly eliminated and the remainder continues to be threatened by conversion to other uses and nonnative plants such as Scotch broom. Petitioned for listing in 2002, the species priority rank is 3.

• The Kittlitz's Murrelet inhabits Alaskan coastal waters and is associated with tidewater glaciers. The current population is estimated at 16,700 birds, a decline of 74 -84% during the past 10-20 years. Recent surveys indicate this downward trend is continuing. Threats include global warming and changes to the marine habitat in the region. Glacial retreat caused by global warming is suspected as a major factor in the population decline. Oil spills and bycatch are threaten the species, which was first petitioned in 2001, and is now ranked with a listing priority of 2.

• The Xantus's Murrelet inhabits the coast of the Southern California and Mexico, and only nests on the Channel Islands off southern California, and on islands off Baja California, Mexico. The population has declined as much as 70% due to predators such as feral cats and rats, and the species has been extirpated from three Mexican islands. This problem is being successfully addressed by removing predators from many of the islands. Light pollution has also been identified as a problem because it makes the species more susceptible to predation and separates disoriented chicks from their parents. Originally petitioned in 2002, it has a listing priority of 5.

• The Lesser Prairie-Chicken, which inhabits portions of Colorado, Kansas, New Mexico, Oklahoma and Texas, has declined by 92% since the 1800s according to FWS. The most serious threat to the species is loss, fragmentation, and modification of its habitat, including lands managed under the Conservation Reserve Program being converted to cropland, including biofuel production. Originally petitioned for listing in 1995, the agency has found that threats to the species are increasing, and as a result the priority rating for listing was raised from an 8 to a 2.

• The Band-rumped Storm-Petrel (Hawaii population) has suffered a severe population decline caused by predation from humans, cats, mongoose, Barn Owls, and rats. Collision with towers and buildings is also a significant threat. Originally petitioned in 1989, it has a listing priority of 3.

• The Greater Sage-Grouse (Columbia Basin population) inhabits northern Oregon and central Washington. The primary threat to the species is habitat loss. Originally petitioned in 1999, FWS concluded in 2001 that the species should be listed, but that action was precluded due to other, higher priorities. Listing of the Greater Sage Grouse has become controversial, and questions remain about whether the Columbia Basin population is distinct. FWS will publish an updated finding addressing the Columbia Basin population after completing a status review and 12-month petition finding regarding the western subspecies.

• The Yellow-billed Cuckoo (western population) is threatened by habitat loss and alteration caused by conversion to agriculture and livestock grazing, and pesticides, which reduce prey numbers and poisoning nestlings. Breeding habitat has also been reduced by invasive plants such as tamarisk. Originally petitioned for listing in 1998, it has a listing priority of 3.

• The Spotless Crake inhabits American Samoa and is threatened by small population size, predation by rats and other non-native mammals, loss of its wetland habitat, and natural disturbances such as hurricanes. The species was petitioned for listing in 2004, and has a priority of 3.

• The Friendly Ground-Dove inhabits American Samoa and is threatened by non-native predators, including feral cats and rats, and natural disturbances such as hurricanes. The population size is currently unknown, but is unlikely to number more than a few hundred pairs. It has a listing priority of 9.

• The Elfin-wood Warbler inhabits several locations in Puerto Rico. Recent surveys found 778 in the Maricao Commonwealth Forest and 196 in the Caribbean National Forest. Habitat destruction within the forests, conversion of shade coffee to sun varieties, timber management practices, and natural disturbances such as hurricanes and forest fires threaten the species. Originally petitioned in 2004, it has a listing priority of 5.

A number of other bird species not on the Candidate List moved closer to being listed under the ESA in 2008, including the Black-footed Albatross, the Western population of the Greater Sage-Grouse, the Mono Basin Area Population of the Greater Sage-Grouse, the Ashy Storm-Petrel, Long-tailed Duck, Yellow-billed Loon, and two Hawaiian species, the Akikiki and Akekee that American Bird Conservancy petitioned for listing. The Federal Register Notice is available at http://edocket.access.gpo.gov/2008/pdf/E8-28986.pdf.