Numenius tahitiensis - (Gmelin, 1789)
Bristle-thighed Curlew
Taxonomic Status: Accepted
Related ITIS Name(s): Numenius tahitiensis (J. F. Gmelin, 1789) (TSN 176604)
French Common Names: Courlis d'Alaska
Unique Identifier: ELEMENT_GLOBAL.2.104761
Element Code: ABNNF07030
Informal Taxonomy: Animals, Vertebrates - Birds - Shorebirds
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Charadriiformes Scolopacidae Numenius
Genus Size: C - Small genus (6-20 species)
Check this box to expand all report sections:
Concept Reference
Help
Concept Reference: American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Concept Reference Code: B98AOU01NAUS
Name Used in Concept Reference: Numenius tahitiensis
Taxonomic Comments: Whimbrel (Numenius phaeopus) is generally accepted as the closest relative of N. tahitiensis (Marks et al. 2002).
Conservation Status
Help

NatureServe Status

Global Status: G2
Global Status Last Reviewed: 22Oct2008
Global Status Last Changed: 11Mar1997
Rounded Global Status: G2 - Imperiled
Reasons: Breeding population consists of only 3,200 pairs in small areas in Alaska; trend is unknown; wintering populations may be threatened by significant habitat loss, predation, and disturbance. GRANK needs further review; NatureServe Rank Calculator Version 6.2 yielded a rank of G3.
Nation: United States
National Status: N2B,NNRN (26Oct2000)

U.S. & Canada State/Province Status
United States Alaska (S2B), Hawaii (S1S2N)

Other Statuses

IUCN Red List Category: VU - Vulnerable

NatureServe Global Conservation Status Factors

Range Extent: 20,000-200,000 square km (about 8000-80,000 square miles)
Range Extent Comments: Breeding range encompasses remote mountainous regions of western Alaska in the Andreafsky Wilderness Area north of the Yukon River mouth and on the central Seward Penninsula (McCaffery and Peltola 1986, Kessel 1989, Gill et al. 1990, Marks et al. 2002). Nonbreeding individuals occur in summer on coastal tundra from Kotzebue Sound south to Hooper Bay and occasionally in the Hawaiian Islands (AOU 1998).

Critical migration staging areas in Alaska include the coastal portions of the central and southern Yukon-Kuskokwim River Delta. The only currently known critical stopover site south of Alaska is the Northwestern Hawaiian Islands. Other possible migration stopover areas include the southern Line Islands, and the Phoenix, or Marshall island groups (Palmisano 1993).

During the nonbreeeding season, this species occurs on Pacific Ocean islands and atolls from the Hawaiian (most commonly from Midway east to French Frigate Shoals) and Marshall islands south to the Fiji, Tonga, Samoa, Marquesas, and Tuamotu islands (Gill and Redmond 1992, AOU 1998, Marks et al. 2002). Bristle-thighed curlew is unique among migratory shorebirds in wintering on remote islands (Marks et al. 1990). Subadults may remain in the Pacific until they are nearly 3 years old (Collar et al. 1992).

Coded range extent refers to breeding range.

Number of Occurrences: 21 - 80
Number of Occurrences Comments: Two known and one suspected breeding areas exist in Alaska, but the number of distinct occurrences has not been determined using standardized criteria. Four key staging areas are known (on the Yukon-Kuskokwim Delta) (Gill and Tibbitts 1990). The number of wintering ground occurrences is uncertain due to the wide dispersion of the birds on South Pacific Islands (Gill and Redmond 1992).

Population Size: 2500 - 10,000 individuals
Population Size Comments: Total population is approximately 10,000 birds (range 7,500-11,800; Morrison et al. 2001). Total breeding population is among the smallest of all North American shorebirds, estimated at 3,200 breeding pairs based on surveys of suitable habitat in the two Alaska breeding areas; approximately 60% in Nulato Hills and 40% on Seward Peninsula (Marks et al. 2002). A third population may exist north of Kotzebue, but is believed to number fewer than 100 pairs. Migration counts have recorded a maximum of 5,000 birds at post-breeding staging areas on the Yukon-Kuskokwim Delta of western Alaska (USFWS 1987). Breeding population, as of the early 1990s, was estimated at about 7,000; population trend is unknown (Collar et al. 1992).

Overall Threat Impact: Medium
Overall Threat Impact Comments: Breeding: Apparently no immediate anthropogenic threats exist in breeding habitat (Gill and Handel 1987, Marks et al. 2002). However, resurgence in gold mining on the Seward Peninsula could potentially affect habitat. Travel across the tundra in heavy machinery by mining personnel can lead to localized habitat damage (Lanctot 1990). Oil/mineral exploration is presently not a serious threat due to the financially important Bering Sea fisheries resource; however, oil/mineral exploration may one day replace fisheries as the most economically important commodity in the region (R. Gill, pers. comm. 1998).

Open dumps in villages near the Yukon-Kuskokwim Delta have resulted in an unnaturally high population of Common Ravens, known predators of curlew eggs and chicks. However, predation is not known to be a significant threat.

Staging: Subsistence hunting may pose a threat to birds on the Yukon-Kuskokwim Delta. Hunter surveys indicate a substantial increase in the take of large shorebirds by Native Americans. Because hunter survey forms do not distinguish between curlews, whimbrels, and Bar-tailed Godwits, the extent of curlew harvest is unknown, but estimated from 2002 reports to be between 90 and 100 birds (fide B. McCaffery in R. Gill, pers. comm. 2004).

Nonbreeding: Potential threats include predation by a variety of introduced species, including rats (Rattus spp.), mongoose (Herpestes auropunctatus), feral pigs (Sus scrofa), dogs (Canis familiaris), and cats (Felis catus). Nonbreeding birds are most susceptible to predation during molt and are readily captured at this time by human subsistence hunters (Marks et al. 1990, Marks and Redmond 1994a). However, the degree of predation and its impact on the population are not known. Subsistence harvest is believed to be much lower now than in the past (see Marks et al. 2002). The presence of curlews on atolls in the Tuamotu Archipelago suggests they are resilient to the occurrence of Pacific rats and to the alteration of native habitats. However, lack of data on their historic numbers at these sites makes it difficult to assess the full affect of altered conditions (Tibbitts et al. 2003). Birds are also hunted and captured on steel hooks baited with pieces of coconut (Cocos nucifera; Gill 1998). Habitat is being lost to development of tourist facilities (Marks and Redmond 1994a), and some habitat has been degraded by introduced mammals.

Short-term Trend: Unknown
Short-term Trend Comments: No data are available on long-term or recent trends in the size of the breeding population, but studies on the Seward Peninsula in Alaska indicate that reproduction appears adequate to maintain the current breeding population.

Residents of Rangiroa Atoll in the Tuamotu Archipelago of French Polynesia have indicated that the population has declined in recent years (Gill and Redmond 1992). Fossil evidence suggests that the birds were once common among the main Hawaiian Islands, yet today they are uncommon during migration and rarely overwinter (Marks and Redmond 1994a). It is unclear, however, whether these observations (and other data for localized areas) represent population declines or shifts in island use (Marks et al. 2002).

Given the probable increase in curlew mortality due to widespread establishment of non-native predator populations in their winter range, it seems possible that the curlew population has declined. However, such losses do not necessarily affect the breeding population size, the trend of which is uncertain.

Long-term Trend: Unknown

Intrinsic Vulnerability Comments: Wintering curlews have a flightless molt period during which they are very vulnerable to predation and disturbance from a variety of introduced human commensal animals (cats, dogs, pigs) (Marks et al. 1990, Palmisano 1993).

Other NatureServe Conservation Status Information

Inventory Needs: It would be useful to know the historical distribution and size of the nonbreeding population of curlews. An expanded search for breeding sites is needed in the Kotzebue area north of the Seward Peninsula.

Protection Needs: Important migration stops may exist in the Central Pacific; identification and protection of these sites is needed (Marks and Redmond 1994).

Distribution
Help
Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) Breeding range encompasses remote mountainous regions of western Alaska in the Andreafsky Wilderness Area north of the Yukon River mouth and on the central Seward Penninsula (McCaffery and Peltola 1986, Kessel 1989, Gill et al. 1990, Marks et al. 2002). Nonbreeding individuals occur in summer on coastal tundra from Kotzebue Sound south to Hooper Bay and occasionally in the Hawaiian Islands (AOU 1998).

Critical migration staging areas in Alaska include the coastal portions of the central and southern Yukon-Kuskokwim River Delta. The only currently known critical stopover site south of Alaska is the Northwestern Hawaiian Islands. Other possible migration stopover areas include the southern Line Islands, and the Phoenix, or Marshall island groups (Palmisano 1993).

During the nonbreeeding season, this species occurs on Pacific Ocean islands and atolls from the Hawaiian (most commonly from Midway east to French Frigate Shoals) and Marshall islands south to the Fiji, Tonga, Samoa, Marquesas, and Tuamotu islands (Gill and Redmond 1992, AOU 1998, Marks et al. 2002). Bristle-thighed curlew is unique among migratory shorebirds in wintering on remote islands (Marks et al. 1990). Subadults may remain in the Pacific until they are nearly 3 years old (Collar et al. 1992).

Coded range extent refers to breeding range.

U.S. States and Canadian Provinces
Color legend for Distribution Map
NOTE: The maps for birds represent the breeding status by state and province. In some jurisdictions, the subnational statuses for common species have not been assessed and the status is shown as not-assessed (SNR). In some jurisdictions, the subnational status refers to the status as a non-breeder; these errors will be corrected in future versions of these maps. A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a migratory transient but this will not be indicated on these maps. See other maps on this web site that depict the Western Hemisphere ranges of these species at all seasons of the year.
Endemism: Occurs (regularly, as a native taxon) in multiple nations, but breeds in a single state or province

U.S. & Canada State/Province Distribution
United States AK, HI

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: NatureServe, 2002


U.S. Distribution by County Help
State County Name (FIPS Code)
AK Bethel (CA) (02050), Dillingham (CA) (02070), Nome (CA) (02180), Wade Hampton (CA) (02270)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
19 Togiak (19030305)+, Nushagak Bay (19030306)+, Kuskokwim Delta (19030502)+, Yukon Delta (19040805)+, Unalakleet (19050102)+, Imuruk Basin (19050105)+, Shishmaref (19050201)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Help
Basic Description: A medium-sized shorebird.
General Description: A large brownish shorebird with a moderately long decurved bill, striped head, and tawny unbarred rump. The stiff feathers on the thighs and flanks are not easily seen in the field (NGS 1983).
Diagnostic Characteristics: Differs from the whimbrel (Numenius phaeopus) in being tawnier and by having a tawny unbarred rump, less streaking on the breast, and a paler bill. Bill is much shorter than that of long billed (Numenius americanus) and far eastern curlews (Numenius madagascariensis), longer, thicker, and more curved than in eskimo curlew (Numenius borealis; which averages 7 cm shorter).
Reproduction Comments: Spring migrants usually arrive singly or in groups of two, occasionally in flocks. Males often precede mates by 1-6 days. Females rarely observed before mates in same year. Nest building begins within 1-3 days of arrival. At Nulato Hills (1987-1991), most nests initiated during last two weeks of May with successful nests hatching from 15-30 June. At Neva Creek, median clutch initiation was 24-31 May, about two weeks after arrival of females. Late clutches (initiated 9-18 June) attributed to late arriving females rather than renesting attempts. Median hatching dates 22-28 June with only a few nests hatching in July. Between 95-100% of pairs hatched nests within 8-10 days in two early years and 21-22 days in one late year at Neva Creek. Second brood per season not known to occur (Marks et al. 2002).

Clutch size is typically four eggs (Kyllingstad 1948, McCaffery and Peltola 1986) which are incubated by both sexes for 24-25 days (McCaffery and Gill 1992). In the Nulato Hills of the Yukon Delta National Wildlife Refuge, 80 percent of nests beneath tundra willows hatched, whereas only about 33 percent of nests in the open were successful. Curlew nests constructed near nest sites of aggressively defensive Long-tailed Jaegers (Stercorarius longicaudus) were more successful than those in more isolated areas (McCaffery and Gill 1992). Seven of 9 nests examined by McCaffery and Peltola (1987) in the Nulato Hills were lost to predation.

Chicks are precocial and leave the nest within 12 hours of hatching. Young can fly when 21-24 days old (Lanctot et al. 1995). When 1-4 weeks old, juveniles congregate in brood aggregations (Lanctot et al. 1995). These groups typically remain intact until juveniles depart for staging areas in early August. Brood aggregations generally consist of fewer than 20 juveniles, but can contain up to 30 (McCaffery and Gill 1992, Lanctot et al. 1995). Brood groups studied by Gill et al. (1990) contained an average of 6.5 young (range = 1-12) from a minimum of 1-3 different broods. However, aggregations can include young from as many as 10 broods (Lanctot et al. 1995). Brood aggregations are tended by up to 14 parent birds, sometimes even if the aggregation does not contain any of their own young (Gill et al. 1990, McCaffery and Gill 1992, Lanctot et al. 1995). Brood aggregations move up to two kilometers per day (McCaffery and Gill 1992). Males attend aggregations 10-14 days longer than females (Gill et al. 1990). Brood aggregations often include young of other birds such as Bar-tailed Godwit (Limosa lapponica), American Golden-Plover (Pluvialis dominica), Pacific Golden-Plover (Pluvialis fulva), Whimbrel, Long-tailed Jaeger, and Western Sandpiper (Calidris mauri) (Lanctot et al. 1995). Curlews become reproductively mature in their third year (Marks 1993).

Ecology Comments: Breeding territories encompass approximately 0.5-1.5 square kilometers (Gill et al. 1990) and average densities range from 0.45 birds per square kilometer in early July to 0.04 birds per square kilometer in late July (Gill and Handel 1987). Territory size varies with topography, particularly configuration of drainages, and is smaller for southern population (40-100 ha in Nulato Hills) than for northern population (150-275 ha at Neva Creek). During incubation, adults at Neva Creek regularly travel from nesting territories to communal feeding and roosting areas up to 7 km away. Adults with broods move away from nesting sites, traveling on average 0.3-1.0 km in first week, 0.5-1.6 km (up to 4.4 km) in second and third weeks, and 0.6-1.0 km (up to 2.6 km) in fourth and fifth weeks (Lanctot et al.1995).

On staging grounds, gathers in communal nocturnal roosts (in shallow water ponds) of up to approximately 120 individuals (Tibbitts 1990). The average diurnal flock size on the staging grounds is 3.1 birds (range 1-33; Handel and Dau 1988). Flock size in nonbreeding habitat ranges from a few to more than 100 individuals (Pratt et al. 1987). While on the Pacific islands, many birds lose so many primaries and secondaries during molt that they become flightless for about two weeks; during molt, birds are extremely secretive by day, hiding in dense vegetation (Marks 1993). Adults molt from July through December and juveniles throughout the year (Marks et al. 1990, Marks 1993). Estimated annual survivorship for wintering birds is 80-90% (Marks 1992). The oldest known individual was one killed on Laysan Island that had been banded 23 years, 10 months earlier (Marks 1992).

Potential predators on the breeding grounds include Golden Eagles (Aquila chrysaetos), Rough-legged Hawks (Buteo lagopus), Northern Harriers (Circus cyaneus), Merlins (Falco columbarius), Short-eared Owls (Asio flammeus), Long-tailed Jaegers, Short-tailed Weasels (Mustela erminea), red foxes, and brown bears (Ursus arctos; McCaffery 1990, Lanctot et al. 1995). On breeding grounds, known predators of adults include Gyrfalcon (Falco rusticolus); of eggs, Parasitic Jaeger (Stercorarius parasiticus) and Common Raven (Corvus corax); and of chicks, red fox (Vulpes vulpes), Northern Harrier (Circus cyaneus), Gyrfalcon (Falco rusticolis), Sandhill Crane (Grus canadensis), and Long-tailed Jaeger (McCaffery 1990, Lanctot et al. 1995, Marks et al. 2002)

Forms temporary associations with American and Pacific Golden-Plover (Pluvialis dominica and P. fulva), Whimbrel, Bar-tailed Godwit, Western Sandpiper and Long-tailed Skua (Stercorarius longicaudus). Curlews and other larger-bodied species commonly attack-mobbed predators together, whereas smaller-bodied species generally give alarm calls and circle predators (Lanctot et al.1995).

Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: Y
Mobility and Migration Comments: Flies at least 4,000 km nonstop between Alaska and the northern end of the nonbreeding range in the northwestern Hawaiian Islands. Apparently most curlews residing in the Central and South Pacific fly over Hawaii during northward and southward migrations, undertaking nonstop flights of more than 6,000 kilometers twice each year (one of the longest nonstop flights known for any bird) (Marks et al. 2002). Birds departing the Laysan Islands leave in small flocks (1-22 individuals, mean = 10.7), 25 percent of which are in the company of Pacific Golden-Plovers. Most birds that remain year-round on the Pacific islands are subadults (Marks and Redmond 1994b).

Most northbound migrants arrive at breeding areas in Alaska during first three weeks of May. At Mountain Village, Alaska, the southern end of breeding range, first birds seen 9-18 May from 1944-1947. More recently, first arrivals 3-6 May 1988-1991 in Nulato Hills, 32 km north of Mountain Village, and 8-18 May 1990-1992 at Neva Creek, suggesting earlier arrival for southern population (Marks et al. 2002).

From June-August, gathers on the coastal lowlands of the Seward Peninsula, the coastal fringe of the Yukon-Kuskokwim Delta and the Nushagak Peninsula of Bristol Bay, Alaska, prior to southward migration over ocean (R. Gill, pers. comm. 1998). Birds spend from a few weeks to two months on the staging grounds (Handel and Dau 1988, Gill 1998). Limited information suggests length of stay on Yukon Delta staging area is 2-3 weeks, where birds fatten on fruits that provide energy to fuel southward migration. Juveniles head for staging grounds slightly after adults and leave Alaska from mid-August to early September, unaccompanied by their parents (Marks et al. 2002).

Estuarine Habitat(s): Tidal flat/shore
Terrestrial Habitat(s): Alpine, Grassland/herbaceous, Sand/dune, Tundra
Habitat Comments: Breeding: Breeding occurs in the low, mountainous regions northeast of the lower Yukon River (Nulato Hills) and uplands of the Seward Peninsula, Alaska (Handel and Dau 1988, Marks et al. 2002). Physiography differs markedly between Seward Peninsula and Nulato Hills; the latter is characterized by lower relief, gentler slopes, more complex drainage patterns, and smaller areas of specific habitats (Marks et al. 2002). Breeding areas encompass a mosaic of subarctic and arctic tundra habitats including: low shrub/tussock tundra (Betula nana, Empetrum nigrum, Ledum palustre, Vaccinium spp., Salix spp.), mixed shrub thicket/tundra (Salix spp., Betula nana, and Alnus crispa over tussocks), tall shrubs (Salix alexensis, typically along water courses), and shrub meadow/tundra (species similar to low shrub/tussock tundra but lower and with more bare ground). Sedge (Carex aquatilis, C. bigelowii, Eriphorum spp.) and lichen meadows, though a small fraction of the overall land area, are also important habitats.

Habitat use changes during the breeding season. During pre-nesting, curlews tend to be found primarily in shrub meadow/tundra (33%) and low shrub/tussock (47%); during nesting the birds shift their activities mostly to shrub meadow/tundra; and during brood rearing, adults attending young increase their use of sedge meadows. Younger broods tend to use habitats with a moderate level of tussocks and shrub cover; after fledging they prefer sedge and lichen meadows (Gill et al. 1990).

Foraging microhabitat: Foraging occurs primarily in dwarf-shrub meadow tundra on slopes and ridges, also in wetlands and medium-shrub (0.5-1.0 meters tall) habitats including marshy streambeds, stream shorelines, shallow lakes, moss or grass/sedge understory along margins (rarely interiors) of willow thickets, and lingonberry and Labrador tea (Ledum spp.) understory around dwarf birch thickets. On staging grounds, foraging birds are most common in tundra/meadow mosaic (Marks et al. 2002).

Staging: Staging prior to primary migration occurs on the coastal fringe of the Yukon-Kuskokwim Delta and coastal lowlands of the Seward Peninsula, Alaska. Staging habitats include sedge and graminoid meadows and upland tundra (Handel and Dau 1988). Annual variation in standing crop of fruits of black crowberry and ericaceous shrubs appears to be a major determinant of habitat use. Southward migrants on the central Yukon Delta roost at night in shallow brackish pond edges surrounded by large wet-sedge meadows (Marks et al. 2002).

Nonbreeding: Winter habitats are primarily throughout Polynesia in the Central and South Pacific. This species is unique among migratory shorebirds in that the entire population is confined to islands during the nonbreeding season (Marks et al. 1990). Subadults may remain in the Pacific until they are nearly three years old (Collar et al. 1992). Habitats include ocean terraces or reef flats, ocean beaches, inter-islet channels, lagoon sand beaches, lagoon coral reefs, mudflats, saltpans, coconut groves, and vegetated clearings (Pratt et al. 1987, Gill and Redmond 1992).Gill and Redmond (1992) found that wintering birds were associated principally with saltpans (36%) and inter-islet channels (27%). During molt, flightless birds take shelter during the day in dense stands of bunchgrass (Eragrostis variabilis) (Marks et al. 1990). In the Tuamotu Archipelago, curlews were found on all atolls surveyed, regardless of rat presence or absence. Most birds were detected in coastal habitats either on the ocean (44%) or lagoon shores (41%; Tibbitts et al. 2003).

Adult Food Habits: Carnivore, Frugivore, Invertivore
Immature Food Habits: Carnivore, Frugivore, Invertivore
Food Comments: Breeding and staging: Upon arrival on breeding grounds, consumes previous summer's black crowberries (Empetrum nigrum), lingonberries (Vaccinium vitis-idaea), and bog cranberries (Vaccinium oxycoccus), less frequently bog blueberries (Vaccinium uliginosum) and alpine bearberries (Arctostaphylos alpina); also spiders, beetles, moths, and butterflies. Previous year's berry crop dwindles as season progresses; by early summer curlews switch to blueberry flowers (available in good quantities for 2-3 weeks in June-early July). Insects are probably the most important food for parents and young chicks. By mid-July, adults and older chicks move to areas with plentiful ripening bog blueberries. Migrants on Yukon Delta eat bog blueberries, black crowberries, cloudberries, and a variety of aquatic and terrestrial insects (Marks et al. 2002). After snow melts, shallowly probes tundra for invertebrates, picks individual fruits and flowers off low and prostrate shrubs, occasionally snatches insects off lake surfaces or out of air, shakes pupae out of cocoons, and searches for invertebrates by pulling up and vigorously thrashing small clumps of lichen and moss (clumps then tossed to ground and examined.) Fall staging birds pick berries and glean insects from dwarf shrubs and probe wet meadows, mudflats, slough banks, and bases of water plants for invertebrates (Gabrielson and Lincoln 1959, Gill et al. 1990, McCaffery 1990, Marks et al. 2002).

Non-breeding: Forages principally in terrestrial habitats consuming spiders, land crabs, insects, seabird eggs, lizards, and carrion (Marks 1993). Food too large to be swallowed whole, such as ghost crabs (Ocypode laevis, O. ceratophthalma), are thrown against the ground until broken. Throws pieces of coral against Black-footed (Phoebastria nigripes) and Laysan albatross (P. immutabilis) eggs to break them open and eat them. Smaller, thinned-shelled eggs of shearwaters (Puffinus spp.), petrels (Pterodroma spp.), and terns (Sterna spp.) are broken open by pecking or picking them up and dropping them to the ground (Marks and Hall, 1992). Also eats eggs of frigate birds (Fregata spp.) and boobies (Sula spp.; Johnsgard 1981). Stomach contents of 14 curlews collected in Polynesia contained vegetation, crustaceans, insects, gastropods, and scorpions (Johnsgard 1981).

Adult Phenology: Diurnal
Immature Phenology: Diurnal
Length: 43 centimeters
Weight: 489 grams
Economic Attributes
Help
Economic Comments: Traditionally trapped for food throughout the Tuamotus (Collar et al. 1992).
Management Summary
Help
Stewardship Overview: Threatened principally by predation by humans and human commensal animals in the wintering habitat. Breeding and staging habitat is relatively secure. Best managed by habitat preservation and, where needed, predator control and establishment of regulations prohibiting hunting. Regular monitoring programs need to be established at both ends of the migration route to refine population estimates and access population trends.
Restoration Potential: In the wintering range, will recolonize islands from which predators have been removed. For example, birds recolonized several Phoenix Islands within five months following eradication of domestic cats (Marks and Redmond 1994a).
Preserve Selection & Design Considerations: BREEDING: Because breeding territories are large and broods are very mobile, vast expanses of undisturbed tundra habitat are required to sustain the breeding population. NON-BREEDING: Requires predator-free islands that are uninhabited or sparsely populated by humans.
Management Requirements: Maintenance of predator-free islands and establishment and enforcement of regulations prohibiting harvest within the wintering range is critical (Marks and Redmond 1994a, Marks et al. 1990).
Monitoring Requirements: Breeding birds can be monitored along point-count transects (Gill and Handel 1987, McCaffery and Peltola 1987). A mark-resighting banding technique has been used to monitor birds in the wintering range (Marks and Redmond 1994b). In Oceania, can be captured at night after blinding with lights (Marks and Redmond 1994b). On the breeding grounds, adults can be captured in mist nets as they respond to call of their chicks or taped distress calls of other chicks (Gill et al. 1990).
Management Research Needs: Need to determine conservation status and the ecological requirements that may be limiting curlew populations (Handel and Dau 1988). Also need to determine the extent of the breeding and staging areas, annual survivorship of various age groups, reproductive success and sources of mortality of eggs and chicks, breeding population distinctness using DNA analysis, habitat specificity during molt, the effects of exotic mammalian predators and subsistence hunting on the distribution of wintering birds, routes and timing of migration, locations of principal wintering areas, migratory stopover points, and survival rates of birds on islands with predators versus predator-free islands. Furthermore, population estimates and trends need to be refined using techniques such as mark-resighting, breeding chronology needs to be better defined, and a technique to readily determine age and sex of birds in the field needs to be developed (Gill and Handel 1990, Marks and Redmond 1994b).
Biological Research Needs: Future studies should identify concentrations of wintering birds, determine whether migratory stopover sites exist between Hawaii and the southern end of the wintering grounds, and determine how human subsistence hunting and human commensal predators affect winter habitat use and population trends. In addition, a subset of wintering populations need to be monitored regularly. Islands and atolls that support most wintering curlews need to be identified and protected (Marks and Redmond 1994a).
Population/Occurrence Delineation
Help
Group Name: Shorebirds

Use Class: Breeding
Subtype(s): Feeding Area, Breeding Site
Minimum Criteria for an Occurrence: Evidence of historical breeding, or current and likely recurring breeding, at a given location, minimally a reliable observation of one or more breeding pairs in appropriate habitat. Be cautious about creating EOs for observations that may represent single breeding events outside the normal breeding distribution.
Mapping Guidance: Breeding occurrences include nesting areas as well as foraging areas of nesting adults and broods. Because separations are based on nesting areas, the foraging areas of different occurrences may overlap if nesting birds are traveling to distant places to feed.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance pertains specifically to nesting areas, not to locations of dispersed foraging individuals. For example, nesting areas separated by a gap of more than 5 km are different occurrences, regardless of the foraging locations of individuals from those nesting areas.

The separation distance is an arbitrary value; it is impractical to attempt to delineate shorebird occurrences on the basis of dispersal patterns or metapopulation dynamics. Foraging ranges of some nesting shorebird species (see following) may suggest use of a larger separation distance, but this likely would result in occurrences that are too large and less effective for conservation planning.

Separation distance based on larger 'typical' breeding home ranges with diameters of 1.5 to 3 kilometers. Semipalmated Plovers have breeding home ranges up to 3 square kilometers, i.e. a diameter of just under 2 kilometers (Nol and Blanken 1999). Red-necked Phalaropes have a core home range of 1-3 hectares, but occasionally travel 1.5 kilometers to feed (Rubega et al. 2000). Stilt Sandpipers can forage up to 8 kilometers from nest (Jehl 1973). Mountain Plovers have an average home range of 56.6 hectares (Knopf 1996) but broods typically move 1-2 kilometers shortly after hatching (Knopf and Rupert 1996).

Territories: Common Snipe, 6.4-28.6 hectares (Mueller 1999); Long-billed Dowitcher, 100-300 meter diameter (Johnsgard 1981); golden-plovers, average 10-59 hectares (Johnson and Connors 1996); Long-billed Curlew, 6-20 hectares (Johnsgard 1981).

Nesting densities: Black-bellied Plover, 0.3-2.3 pairs per square kilometer (44 ha per pair at latter density; Hussell and Page 1976, Parmelee et al. 1967); Marbled Godwit, maximum density 1 pair/32 hectares (Stewart and Kantrud 1972).

Foraging distances: Greater and Lesser Yellowlegs, up to 13 kilometers from nest (Elphick and Tibbits 1998, Tibbits and Moskoff 1999).

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): 1.5 km
Inferred Minimum Extent Justification: Based on a smaller 'typical' home ranges (see Separation Justification).
Date: 25Mar2004
Author: Hammerson, G., and S. Cannings

Use Class: Migratory stopover
Subtype(s): Roost, Foraging concentration area
Minimum Criteria for an Occurrence: Evidence of recurring presence of migrating flocks (including historical); and potential recurring presence at a given location, minimally a reliable observation of 25 birds in appropriate habitat (minimum can be reduced in the case of rarer species). Occurrences should be locations where the species is resident for some time during the appropriate season; it is preferable to have observations documenting presence over at least 7 days annually. Be cautious about creating EOs for observations that may represent single events.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance somewhat arbitrary; set at 5 kilometers to define occurrences of managable size for conservation purposes. Occurrences defined primarily on the basis of areas supporting concentrations of foraging or roosting birds, rather than on the basis of distinct populations.
Date: 15Apr2002
Author: Cannings, S.

Use Class: Nonbreeding
Subtype(s): Roost, Winter Feeding Area
Minimum Criteria for an Occurrence: Evidence of recurring presence of wintering flocks (including historical); and potential recurring presence at a given location, minimally a reliable observation of 25 birds in appropriate habitat. Occurrences should be locations where the species is resident for some time during the appropriate season; it is preferable to have observations documenting presence over at least 20 days annually. Be cautious about creating EOs for observations that may represent single events.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance somewhat arbitrary; set at 5 kilometers to define occurrences of managable size for conservation purposes. Occurrences defined primarily on the basis of areas supporting concentrations of foraging or roosting birds, rather than on the basis of distinct populations.
Date: 25Mar2004
Author: S. Cannings
Population/Occurrence Viability
Help
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Help
Authors/Contributors
Help
NatureServe Conservation Status Factors Edition Date: 22Oct2008
NatureServe Conservation Status Factors Author: Palis, J., T. A. Gotthardt, E. W. West, M. Koenen, G. Hammerson, and D. W. Mehlman. Rev. by R. E. Gill.
Management Information Edition Date: 14Dec1999
Management Information Edition Author: PALIS, J.; REVISIONS BY M. KOENEN AND D.W. MEHLMAN
Management Information Acknowledgments: The author thanks Robert Gill for providing most of the references cited and for reviewing a draft of the document. Funding for the preparation of this abstract was made possible by the U.S. Fish and Wildlife Service, Division of Endangered Species.
Element Ecology & Life History Edition Date: 22Oct2008
Element Ecology & Life History Author(s): Gotthardt, T. A., J. Palis, and G. Hammerson. Reviewed by Robert E. Gill.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • Alaska Natural Heritage Program. 2007. Unpublished distribution maps of Alaskan vertebrates. University of Alaska, Anchorage, Alaska.

  • Allen, A.A., and H. Kyllingstad. 1949. The eggs and young of the bristle-thighed curlew. Auk 66:343-350.

  • American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.

  • American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.

  • Carter, M., C. Hunter, D. Pashley, and D. Petit. 1998. The Watch List. Bird Conservation, Summer 1998:10.

  • Collar, N. J., L. P. Gonzaga, N. Krabbe, A. Madroņo-Nieto, L. G. Naranjo, T. A. Parker III, and D. C. Wege. 1992. Threatened Birds of the Americas. The ICBP/IUCN Red Data Book. 3rd edition, Part 2. International Council for Bird Preservation, Cambridge, UK.

  • Dunning, J. B., Jr. 1993. CRC handbook of avian body masses. CRC Press, Boca Raton.

  • Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1992. Birds in Jeopardy: the Imperiled and Extinct Birds of the United States and Canada, Including Hawaii and Puerto Rico. Stanford University Press, Stanford, California. 259 pp.

  • Ely, C. R., and D. G. Raveling. 1984. Breeding biology of Pacific white-fronted geese. J. Wildl. Manage. 48:823-837.

  • Gabrielson, I. N. and F. C. Lincoln. 1959. The Birds of Alaska. Stackpole, Harrisburg, Pennsylvania, and Wildlife Management Institute, Washington, D.C.

  • Gill, R.E, Jr. 1992. Review of status of the Bristle-thighed Curlew under the Endangered Species Act. Memorandum (10 February 1992) to Dirk Derksen, Direcotor, Alaska Fish and Wildlife Research Center. 5 pp.

  • Gill, R.E. Jr., and R. L. Redmond. 1992. Distribution, numbers, and habitat of bristle-thighed curlews (Numenius tahitiensis) on Rangiroa atoll. Notornis 39:17-26.

  • Gill, R.E., Jr. 1998. Personal communication. Robert Gill, U.S. Fish and Wildlife Service, 1011 E. Tudor Rd, Anchorage, AK.

  • Gill, R.E., Jr. 1998. Trouble in paradise: the bristle-thighed curlew. WWF Arctic Bulletin 3.98:12-13.

  • Gill, R.E., Jr. and C.M. Handel. 1987. The status of the bristle-thighed curlew (Numenius tahitiensis): Should we be concerned? U.S. Fish and Wildlife Service paper presented at the Alaska Bird Conference and Workshop, 3-4 April 1987 Centennial Hall, Juneau, AK.

  • Gill, R.E., Jr. and T.L. Tibbitts. 1990. Autumn staging in bristle-thighed curlews. Paper presented before the joint meeting of the American Ornithologists' Union and the Cooper Ornithologist Society; June 25-30, 1990. Univ. of California, Los Angeles. U.S. Dept. Interior, Fish and Wildlife Service, Anchorage, AK. 20 p.

  • Gill, R.E., Jr., B.J. McCaffery, and T.G. Tobish. 1988. Bristle-thighed curlews, biologists and bird tours--a place for all. Birding 20(3):148-155.

  • Gill, R.E., Jr., C.M. Handel, M.M. Vacca, and J.S. Marks. 1989. A year in the life of a bristle-thighed curlew: Studies throughout its range and annual cycle. Paper read at the Fourth Alaska Bird Conference, Univ. of Alaska, 20-22 March 1989. U.S. Fish and Wildlife Service, Anchorage, AK. 20 p.

  • Gill, R.E., Jr., R.B. Lanctot, J.D. Mason, and C.M. Handel. 1990. Observations on habitat use, breeding chronology, and parental care in bristle-thighed curlews on the Seward Peninsula, Alaska. Wader Study Group Bulletin 61:28-36.

  • Gill, R.E., Jr., and C.M. Handel. 1990. Data gaps and priorities for research. In Proceedings of the Bristle-thighed Curlew workshop (R.E. Gill, Jr. and C.M. Handel, compilers), Anchorage, AK.

  • Handel, C. M., and C. P. Dau. 1988. Seasonal occurrence of migrant whimbrels and bristle-thighed curlews on the Yukon-Kuskokwim Delta, Alaska. Condor 90:782-790.

  • Handel, C.M., R.B. Lanctot, B.J. McCaffery, and G. Peltola, Jr. 1990. Distribution and population estimate of breeding bristle-thighed curlew. Paper presented before the joint meeting of the American Ornithologists Union and the Cooper Ornithological Society; 1990 June 25-30; Univ. of California, Los Angeles. U.S. Fish and Wildlife Service, Anchorage, AK. 26 p.

  • Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.

  • Isleib, M.E., and B. Kessel. 1973. Birds of the North Gulf Coast-Prince William Sound Region, Alaska. Biological Papers of the University of Alaska, Number 14, Fairbanks.

  • Jehl, J. R., Jr. 1973. Breeding biology and systematic relationships of the stilt sandpiper. Wilson Bulletin 85:115-147.

  • Johnsgard, P. A. 1981. The plovers, sandpipers, and snipes of the world. Univ. Nebraska Press, Lincoln. 493 pp.

  • Kessel, B. 1989. Birds of the Seward Peninsula, Alaska: their biogeography, seasonality, and natural history. Univ. of Alaska Press, Fairbanks, AK. 330 pp.

  • Knopf, F.L. 1996. Mountain Plover (Charadrius montanus). In A. Poole and F. Gill, editors. The Birds of North America, No. 211. The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, DC. 16 pp.

  • Knopf, F.L., and J.R. Rupert. 1996. Productivity and movements of mountain plovers breeding in Colorado. Wilson Bulletin 108:28-35.

  • Kyllingstad, H.C. 1948. The secret of the bristle-thighed curlew. Arctic 1(2):113-118.

  • Lanctot, R. B., R. E. Gill, Jr., T. L. Tibbitts, and C. M. Handel. 1995. Brood amalgamation in the bristle-thighed curlew, Numenius tahitiensis: process and function. Ibis 137:559-569.

  • Lanctot, R.B. 1990. Breeding ecology of bristle-thighed curlews, Numenius tahitiensis at Neva Creek, Seward Peninsula. Pages 4-6 in Summary of the Proceedings From the Workshop on Bristle-thighed Curlews (R.E. Gill, Jr., and C.M. Handel, compilers). U.S. Fish and Wildlife Service, Anchorage, AK.

  • Marks, J. S. 1992. Longevity record for the bristle-thighed curlew: an extension. Journal of Field Ornithology 63:309-310.

  • Marks, J. S. 1993. Molt of bristle-thighed curlews in the northwestern Hawaiian Islands. Auk 110:573-787.

  • 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.

  • Marks, J. S., and R. L. Redmond. 1994b. Migration of bristle-thighed curlews on Laysan Island: timing, behavior, and estimated flight range. Condor 96:316-330.

  • Marks, J.S., R.L. Redmond, P. Hendricks, R.B. Clapp, and R.E. Gill, Jr. 1990. Notes on longevity and flightlessness in bristle-thighed curlews. Auk 107:779-781.

  • Marks, J.S., T.L. Tibbits, R.E. Gill, and B. J. McCaffery. 2002. Bristle-thighed Curlew (Numenius tahitiensis). In: A. Poole and F. Gill, (eds.). The Birds of North America, No.705. The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.

  • Marks, J.S., and C.S. Hall. 1992. Tool use by Bristle-thighed Curlews feeding on albatross eggs. Condor 94(4):1032-1034.

  • McCaffery, B. J. and G. Peltola, Jr. 1987. The status of breeding bristle-thighed curlews (Numenius tahitiensis) at two sites in the southern Nulato Hills. Unpublished report. Yukon Delta National Wildlife Refuge, Bethel, Alaska.

  • McCaffery, B.J. 1989a. Factors contributing to reproductive success in the bristle-thighed curlew (Numenius tahitiensis). U.S. Fish and Wildlife Service paper presented to Alaska Bird Conference, Univ. of Alaska Fairbanks; 20-22 March 1989; Fairbanks, AK.

  • McCaffery, B.J. 1989b. Observations of the nesting biology of bristle-thighed curlews and whimbrels in the southern Nulato Hills: A progress report. U.S. Fish and Wildlife Service.

  • McCaffery, B.J. 1990. Breeding ecology of bristle-thighed curlews at Curlew Lake. Pages 7-8 in Summary of the Proceedings From the Bristle-thighed Curlew Workshop (R.E. Gill, Jr., and C.M. Handel, compilers). U.S. Fish and Wildlife Service, Anchorage, AK.

  • McCaffery, B.J. 1990. Comparative nesting ecology of sympatric NUMENIUS curlews in western Alaska. In research files, U.S. Fish and Wildlife Service, Anchorage, AK. 14 p.

  • McCaffery, B.J. and G. Peltola, Jr. 1986. The status of the bristle-thighed curlew on the Yukon Delta National Wildlife Refuge. Wader Study Group Bull. 47:22-25.

  • McCaffery, B.J. and R.E. Gill, Jr. 1992. Antipredator strategies in breeding bristle-thighed curlews. Amer. Birds 46(3):378-383.

  • Mlodinow, S. G., S. Feldstein, and B. Tweit. 1999. The bristle-thighed curlew landfall of 1998: climatic factors and notes on identification. Western Birds 30:133-155.

  • Morrison, R. I. G., R. E. Gill, Jr., B. A. Harrington, S. Skagen, G. W. Page, C. L. Gratto-Trevor, and S. M. Haig. 2001. Estimates of shorebird populations in North America. Occasional Paper Number 104, Canadian Wildlife Service, Environment Canada, Ottawa, ON. 64 pages.

  • National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.

  • Nol, E., and M. S. Blanken. 1999. Semipalmated Plover (Charadrius semipalmatus). No. 444 IN A. Poole and F. Gill, eds. The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 24pp.

  • Palmisano, A. W. 1993. Management recommendation for Bristle-thighed curlews. Memo to USFWS Regional Directors, Regions 7 and 8. March 9, 1993. 5p.

  • Pratt, H. D., P. L. Bruner, and D. G. Berrett. 1987. A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press, Princeton, New Jersey. 409 pp. + 45 plates.

  • Rubega, M. A., D. Schamel, and D. M. Tracy. 2000. Red-necked Phalarope (Phalaropus lobatus). No. 538 IN A. Poole and F. Gill, editors, The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 28pp.

  • Shallenberger, R. J. (ed.). 1981. Hawaii's birds. Third edition. Hawaii Audubon Society, Honolulu, Hawaii. 96 pp.

  • Sibley, D. A. 2000a. The Sibley guide to birds. Alfred A. Knopf, New York.

  • Swanson, J. D., M. Schuman, and P. C. Scorup. 1985. Range survey of the Seward Peninsula, Alaska. USDA Soil Conservation Service, Anchorage, AK. 77 pp. plus maps.

  • Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.

  • Tibbitts T.L., R.B. Lanctot, E. VanderWerf, and V.A. Gill. 2003. Survey for Arctic-breeding shorebirds in the Tuamotu Archipelago, French Polynesia, March 2003. Unpublished report for the U.S. Fish and Wildlife Service and the U.S. Geological Survey.

  • Tibbitts, L. 1990. Phenology and habitat use during ground surveys of the Yukon-Kuskokwim River Delta. Pages 11-13 in Summary of the Proceedings From the Bristle-thighed Curlew Workshop (R.E. Gill, Jr., and C.M. Handel, compilers). U.S. Fish and Wildlife Service, Anchorage, AK.

  • U.S. Fish and Wildlife Service (USFWS). 1987. Migratory nongame birds of management concern in the United States: the 1987 list. U.S. Fish and Wildlife Service, Office of Migratory Bird Management, Washington, D.C. 63 pp.

  • van Gils, J. and P. Wiersma. 1996. Family Scolopacidae (sandpipers, snipes and phalaropes). Pages 489-533 in J. del Hoyo, A. Elliott, and J. Sargatal (Eds.) Handbook of the birds of the world. Vol. 3. Lynx Editions, Barcelona, Spain.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at http://explorer.natureserve.org were updated to be current with NatureServe's central databases as of November 2016.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2017 NatureServe, 4600 N. Fairfax Dr., 7th Floor, Arlington Virginia 22203, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.