Conservation and Management

Shooting And Trapping

Historic harvest of adults and eggs by indigenous people in w. Alaska likely but unconfirmed (see McCaffery and Gill 2001 McCaffery, B., and R. Gill (2001). Bar-tailed Godwit (Limosa lapponica). In The Birds of North America, No. 581 (A. Poole and F. Gill, Editors). The Birds of North America, Inc., Philadelphia, Pennsylvania, USA. Close ). Annual subsistence harvest of “large shorebirds” on Yukon Delta from 1995 to 1998 may have included this species (see Wentworth and Seim 1996 Wentworth, C. and S. Seim. (1996). Subsistence waterfowl harvest survey: Yukon-Kuskokwim Delta, comprehensive report 1985-1995 and result 1995. Anchorage, AK: U.S. Fish Wildl. Serv. Close , Wentworth and Wong 1999 Wentworth, C. and D. Wong. (1999). Migratory bird subsistence harvests: Yukon-Kuskokwim Delta and Bristol Bay, 1995-1998. Anchorage,AK: U.S. Fish Wildl. Serv. Close ). In Oceania, shot or trapped in Line Is. (Kirby 1925 Kirby, Jr., H. (1925). The birds of Fanning Island, central Pacific Ocean. Condor 27:185-197. Close ), Gilbert Is. (Child 1956 Child, P. (1956). Birds of the Gilbert and Ellice Islands Colony. Gilbert and Ellice Islands Colony Education Departament, Bikenibeu, Tarawa. Close ), Cook Is. (Burland 1964 Burland, J. C. (1964). Some notes on the bird life of Palmerston Atoll. Notornis 11:145-154. Close , Holyoak 1980 Holyoak, D. T. (1980). Guide to Cook Islands birds. Wellington, New Zealand: Cook Islands Library and Mus. Soc. Close ), Marquesas Is. (Holyoak 1975a Holyoak, D. T. (1975a). Les oiseaux des isles Marquises. Oiseau Rev. Fr. Ornithol. 45:207-234. Close ), Tokelau Is. (Wodzicki and Laird 1970 Wodzicki, K. and M. Laird. (1970). Birds and bird lore in the Tokelau Islands. Notornis 17:247-276. Close ), and Tuamotu Archipelago (Bruner 1972 Bruner, P. L. (1972). Field guide to the birds of French Polynesia. Honolulu, HI: Bernice P. Bishop Mus. Close , Gill and Redmond 1992 Gill, Jr., R. E. and R. L. Redmond. (1992). Distribution, numbers, and habitat of Bristle-thighed Curlews (Numenius tahitiensis) on Rangiroa Atoll. Notornis 39:17-26. Close ), but extent of take unknown (Gill and Redmond 1992 Gill, Jr., R. E. and R. L. Redmond. (1992). Distribution, numbers, and habitat of Bristle-thighed Curlews (Numenius tahitiensis) on Rangiroa Atoll. Notornis 39:17-26. Close , Marks and Redmond 1994a Marks, J. S. and R. L. Redmond. (1994a). Conservation problems and research needs for Bristle-thighed Curlews Numenius tahitiensis on their wintering grounds. Bird Conservation International 4:329-341. Close ). Formerly shot on main Hawaiian Is. (Henshaw 1902a Henshaw, H. W. (1902a). Birds of the Hawaiian Islands being a complete list of the birds of the Hawaiian possessions with notes on their habits. Honolulu, HI: Thomas G. Thrum. Close , Munro 1960 Munro, G. C. (1960). Birds of Hawai'i. Charles E. Tuttle Company, Rutland, VT, USA. Close ), but practice halted decades ago. In addition to shooting and capture by hand during flightless period on wintering grounds (Marks et al. 1990 Marks, J. S., R. L. Redmond, P. Hendricks, R. B. Clapp and Jr. Gill, R. E. (1990). Notes on longevity and flightlessness in Bristle-thighed Curlews. Auk 107:779-781. Close , Gill and Redmond 1992 Gill, Jr., R. E. and R. L. Redmond. (1992). Distribution, numbers, and habitat of Bristle-thighed Curlews (Numenius tahitiensis) on Rangiroa Atoll. Notornis 39:17-26. Close ), curlews also caught on fish hooks baited with coconut meat (Bruner 1972 Bruner, P. L. (1972). Field guide to the birds of French Polynesia. Honolulu, HI: Bernice P. Bishop Mus. Close ). At present, harvest on wintering grounds thought to be much lower than in past (G. McCormack, P. Raust, G. Sanford, and U. Bukaireiti pers. comm.). Needs study.

Pesticides And Other Contaminants

No information. Nuclear weapons testing in Marshall Is., Line Is., and Tuamotu Archipelago likely contaminated habitats on many wintering islands, but effects on curlews unknown (Gill and Redmond 1992 Gill, Jr., R. E. and R. L. Redmond. (1992). Distribution, numbers, and habitat of Bristle-thighed Curlews (Numenius tahitiensis) on Rangiroa Atoll. Notornis 39:17-26. Close , R. Redmond pers. comm.).

Ingestion Of Plastics, Lead, Etc

Adult on Laysan I. made repeated unsuccessful attempts to swallow 2-cm diameter white plastic ball, apparently mistaking it for egg (JSM). Ingestion of ubiquitous plastic garbage on northern part of winter range likely but not confirmed. Curlews on Midway Atoll forage in soils contaminated with lead, but lead levels in curlews have not been assessed (K. Larsen pers. comm.).

Collisions With Stationary/Moving Structure Or Objects

No information on collisions with human-made objects. Small numbers of broken-winged curlews (1 or 2 each visit) on Laysan I. 1998–1991 presumed to have collided in flight with seabirds (Marks 1995 Marks, J. S. (1995). Migratory behaviour of curlews with broken wings. Wader Study Group Bulletin 76:37-38. Close ).

Fishing Nets

No information.

Degradation Of Habitat

Breeding habitat largely intact, although off-road vehicles (usually associated with mining) continue to degrade tundra habitat on Seward Peninsula (TLT, REG). Fires (mostly from lightning strikes, but occasionally human caused) regular agent of habitat change in both breeding areas; however, curlews nested in Nulato Hills sites 1–3 yr after burns, some areas still with charred vegetation (BJM).

Habitat modification severe on many parts of winter range (e.g., Wodzicki 1981 Wodzicki, K. (1981). Some nature conservation problems in the South Pacific. Biological Conservation 21:5-18. Close , Kirch 1983b Kirch, P. V. (1983b). Man's role in modifying tropical and subtropical Polynesian ecosystems. Archaeol. Oceania 18:26-31. Close , Steadman 1989 Steadman, D. W. (1989). Extinction of birds in eastern Polynesia: a review of the record, and comparisons with other Pacific island groups. Journal of Archaeological Science 16(2):177–205. Close , James 1995a James, H. F. (1995a). Prehistoric extinctions and ecological changes on oceanic islands. Ecol. Stud. 115:87-102. Close ), but degradation per se probably not as important to curlews as predation by introduced mammals (Gill and Redmond 1992 Gill, Jr., R. E. and R. L. Redmond. (1992). Distribution, numbers, and habitat of Bristle-thighed Curlews (Numenius tahitiensis) on Rangiroa Atoll. Notornis 39:17-26. Close , Marks and Redmond 1994a Marks, J. S. and R. L. Redmond. (1994a). Conservation problems and research needs for Bristle-thighed Curlews Numenius tahitiensis on their wintering grounds. Bird Conservation International 4:329-341. Close ). Curlews suffered when European rabbits removed vegetation on Laysan I. 1903–1923; availability of insect food decreased, seabird eggs became mainstay of diet, and many curlews were found sick or dead (field notes of A. Wetmore in Olson 1996a Olson, S. L. (1996a). History and ornithological journals of the Tanager Expedition of 1923 to the Northwestern Hawaiian Islands, Johnston and Wake Islands. Atoll Research Bulletin 433:1–210. Close ; see Diet and Foraging: Diet, above).

Disturbance At Nest And Roost Sites

Most of breeding grounds very difficult to access. Disruption to nesting birds by birders initially thought to be problem (Gill et al. 1988 Gill, Jr., R. E., B. J. McCaffery and T. G. Tobish. (1988). Bristle-thighed Curlews, biologists, and bird tours: a place for all. Birding 20:148-155. Close ), but high dispersion of nests and subsequent knowledge of seasonal nesting behavior and response to humans suggest this not the case (Gill 1991 Gill, Jr., R. (1991). Bristle-thighed Curlew update. Birding 23:59. Close ). On autumn staging grounds in Alaska, controlled studies (20 trials, 20 flocks representing 286 birds) to assess reaction of curlews to low-flying aircraft (66 m above ground) revealed all birds responded by flushing an average of 500 m ahead of plane; most birds circled behind plane and landed in general area where flushed (REG). On wintering grounds, roosting birds often quick to take flight on islands where persecuted by humans (Bakus 1967 Bakus, G. J. (1967). Changes in the avifauna of Fanning Island, central Pacific, between 1924 and 1963. Condor 69:207-209. Close , Pearson and Knudsen 1967 Pearson, D. L. and J. W. Knudsen. (1967). Avifaunal records from Eniwetok Atoll, Marshall Islands. Condor 69:201-203. Close , Child 1979 Child, P. (1979). Some bird observations from Western Samoa. Notornis 26:171-179. Close , Gill and Redmond Gill and Redmond 1992 Gill, Jr., R. E. and R. L. Redmond. (1992). Distribution, numbers, and habitat of Bristle-thighed Curlews (Numenius tahitiensis) on Rangiroa Atoll. Notornis 39:17-26. Close ); generally tamer elsewhere (e.g., Fosberg 1966 Fosberg, F. R. (1966). Northern Marshall Islands land biota: birds. Atoll Research Bulletin 114. Close , Marks and Redmond 1994a Marks, J. S. and R. L. Redmond. (1994a). Conservation problems and research needs for Bristle-thighed Curlews Numenius tahitiensis on their wintering grounds. Bird Conservation International 4:329-341. Close , Dutson 2001 Dutson, G. (2001). New distributional ranges for Melanesian birds. Emu 101:237-248. Close ), but exceptions (G. McCormack pers. comm.).

Direct Human/Research Impacts

Incubating birds typically sit tight during routine nest checks by researchers (REG, BJM, TLT). Roosting birds on Yukon Delta disturbed by humans walking toward them, but birds readily returned to roosts (TLT, REG). Human presence and/or capture of adults in brood-rearing areas elicits antipredator behavior from adults; if prolonged, young broods vulnerable to exposure to elements.

Two of 171 adults caught on breeding grounds with mist-net strung between poles could not fly upon release, 1 had unknown fate and 1 was taken into captivity for rehabilitation; 2 birds died from apparent stress during banding (REG, TLT, BJM). After color-banding in Nulato Hills, a few chicks gained mass more slowly than did unbanded or metal-only banded siblings, suggesting band effects on growth (BJM). None of 420 curlews captured in Northwestern Hawaiian Is. using a spotlight and hoop net at night was injured; however, 2 birds subsequently died when held overnight (JSM).

Several birds given backpack-mounted radio transmitters on Laysan I. got lower mandibles caught in harness and would have died had researchers not removed transmitters (JSM). Six of 11 adults fitted with same harness-mounted transmitters on breeding grounds failed to return in subsequent years and presumably died after entanglement in harnesses; 5 others shed transmitters, but only 2 of these subsequently returned to nest near original territories (REG, TLT, BJM). In contrast, 19 of 20 curlews fitted on breeding grounds with small transmitters (3 g) sewn or glued to scapular feathers or glued to leg bands returned and bred in subsequent years (REG, TLT), highlighting importance of using nonharness attachments for radio transmitters.

Conservation Status

Listed as “Vulnerable” by BirdLife International (BirdLife International 2000 BirdLife International. (2000). Threatened birds of the world: the official source for birds on the IUCN red list. Barcelona, Spain, and Cambridge, U.K: Lynx Edicions and BirdLife International. Close ) owing to small and supposedly declining population size and putative predation by exotic mammals on wintering islands, where many adults become flightless during molt (Marks Marks 1993 Marks, J. S. (1993). Molt of Bristle-thighed Curlews in the northwestern Hawaiian Islands. Auk 110:573-587. Close , Marks 1996 Marks, J. S. (1996). Red data bird: Bristle-thighed Curlew. World Birdwatch 18:20-21. Close ). Given profound negative influence of humans on biota of oceanic islands (Atkinson and Atkinson 2000 Atkinson, A. and T. Atkinson. (2000). "Land vertebrates as invasive species on islands served by the South Pacific Environment Programme." In Invasive species in the Pacific: a technical review and draft regional strategy, 19-83. Apia, Western Samoa: South Pacific Regional Eviron. Programme. Close ), concern probably well deserved. However, virtually no data exist on population trends (see Demography and Populations: Population Status, above) or predation on wintering grounds.

Measures Proposed And Taken

Fully protected in contiguous U.S. and Canada under Migratory Bird Treaty Act of 1918 and in Alaska and Hawaiian Is. following statehood. Most of breeding range of southern population within Andreafsky Wilderness of Yukon Delta National Wildlife Refuge (NWR), but one-quarter on private lands just south of wilderness area. Wintering birds receive added protection within Hawaiian Is. NWR, Midway Atoll NWR, and satellite NWRs in Central and South Pacific on Baker I., Howland I., Jarvis I., Johnston Atoll, and Rose Atoll. Wildlife reserves also established in parts of Line Is. (Perry 1980 Perry, R. (1980). Wildlife conservation in the Line Islands, Republic of Kiribati (formerly Gilbert Islands). Environmental Conservation 7:311-318. Close , International Union for Conservation of Nature [IUCN] International Union for the Conservation of Nature 1991 International Union for the Conservation of Nature (1991). IUCN directory of protected areas in Oceania. International Union for the Conservation of Nature, Cambridge, UK. Close ), Phoenix Is. (IUCN International Union for the Conservation of Nature 1991 International Union for the Conservation of Nature (1991). IUCN directory of protected areas in Oceania. International Union for the Conservation of Nature, Cambridge, UK. Close ), Marquesas Is. (IUCN International Union for the Conservation of Nature 1991 International Union for the Conservation of Nature (1991). IUCN directory of protected areas in Oceania. International Union for the Conservation of Nature, Cambridge, UK. Close ), Cook Is. (IUCN International Union for the Conservation of Nature 1991 International Union for the Conservation of Nature (1991). IUCN directory of protected areas in Oceania. International Union for the Conservation of Nature, Cambridge, UK. Close , Mccormack 1991 Mccormack, G. (1991). Takutea: a wildlife report from 1986 to 1990. Rarotonga, Cook Islands: Prime Minister's Dep. Close ), and Tuamotu Archipelago (IUCN International Union for the Conservation of Nature 1991 International Union for the Conservation of Nature (1991). IUCN directory of protected areas in Oceania. International Union for the Conservation of Nature, Cambridge, UK. Close ).

Marks and Redmond (Marks and Redmond 1994a Marks, J. S. and R. L. Redmond. (1994a). Conservation problems and research needs for Bristle-thighed Curlews Numenius tahitiensis on their wintering grounds. Bird Conservation International 4:329-341. Close ) posited the following needs for Bristle-thighed Curlew conservation in Oceania: (1) identification of high concentrations of wintering birds, (2) identification of migratory stopover sites (if any) south of Hawaiian Is., (3) monitoring of population trends, and (4) protection and management of key islands and atolls throughout winter range (see Priorities for Future Research, below). In addition, Sherley (Sherley 2001 Sherley, G. (2001). Bird conservation priorities and a draft avifauna conservation strategy for the Pacific Islands Region. Apia, Western Samoa: South Pacific Regional Environ. Programme. Close : 31) noted that Bristle-thighed Curlews “be the subject of education initiatives, habitat reserves, [and] legislative protection” in Oceania and called for research on habitat requirements and effects of introduced predators.

Effectiveness Of Measures

Owing to recent publications (e.g., Marks and Redmond 1994a Marks, J. S. and R. L. Redmond. (1994a). Conservation problems and research needs for Bristle-thighed Curlews Numenius tahitiensis on their wintering grounds. Bird Conservation International 4:329-341. Close , Marks 1996 Marks, J. S. (1996). Red data bird: Bristle-thighed Curlew. World Birdwatch 18:20-21. Close , BirdLife International 2000 BirdLife International. (2000). Threatened birds of the world: the official source for birds on the IUCN red list. Barcelona, Spain, and Cambridge, U.K: Lynx Edicions and BirdLife International. Close , Sherley 2001 Sherley, G. (2001). Bird conservation priorities and a draft avifauna conservation strategy for the Pacific Islands Region. Apia, Western Samoa: South Pacific Regional Environ. Programme. Close , Blanvillain et al. Blanvillain et al. 2002 Blanvillain, C., C. Florent and V. Thenot. (2002). Land birds of Tuamotu Archipelago, Polynesia: relative abundance and changes during the 20th century with particular reference to the critically endangered Polynesian Ground-Dove (Gallicolumba erythroptera). Biological Conservation 103:139-149. Close ), potential threats to curlews on wintering grounds widely recognized. Despite recognition, however, no new conservation practices enacted, so effectiveness of proposed measures unknown.