Habitat

Breeding areas characterized by rolling hills (50–500 m elevation; slopes 3–10%) covered with upland tundra; lower parts of drainages with medium to tall (1.2–2.4 m) shrubs, and upper elevations (ridges and slopes) with extremely short vegetation and/or bare ground. First nests discovered were in dwarf-shrub mat in Nulato Hills (Kyllingstad 1948 Kyllingstad, H. C. (1948). The secret of the Bristle-thighed Curlew. Arctic 1:113-118. Close ), but most recent nests found in dwarf-shrub meadows (mostly hummock-ridge tundra, tussock-shrub tundra) interspersed with wet meadows and patches of low-shrub thickets (0.4–1.1 m tall). Territories encompass several habitat types, some rarely used (e.g., cliffs, tall-shrub drainages). Habitats similar at both breeding areas, but physiography markedly different between Seward Peninsula and Nulato Hills; latter characterized by lower relief, gentler slopes, more complex drainage patterns, and smaller areas of specific habitats.

Dwarf-shrub meadows of several distinct types predominate both breeding areas (after Kessel 1979 Kessel, B. (1979). Avian habitat classification for Alaska. Murrelet 60:86-94. Close ): (1) hummock/ridge tundra—hummocks 0.2–0.7 m tall covered with low shrubs (marsh Labrador tea [Ledum palustre], black crowberry [Empetrum nigrum], bog blueberry [Vaccinium uliginosum], lingonberry [V. vitis-idaea], dwarf birch [Betula nana], willow [Salix spp.]), sedges (Bigelow sedge [Carex bigelowii]), lichens (Cetraria spp., Cladina spp.), mosses (Sphagnum spp., Polytrichum spp.), and variety of herbaceous plants; (2) tussock-shrub tundra—mostly dense cottongrass (Eriophorum vaginatum) 0.1–0.5 m tall with thick growth of low and prostrate shrubs (as above), lichens, and herbaceous plants occurring between tussocks; and (3) sedge/dwarf-shrub bog—moist, graminoid-dominated (water sedge [Carex aquatilis], Bigelow sedge, white cottongrass [E. scheuchzeri]) cover with moss understory and low willows scattered throughout. Also use dwarf-shrub mats (dry tundra, mat fell field, shrub-heath tundra) consisting mainly of black crowberry, mountain-avens (Dryas spp.), lingonberry, and alpine bearberry (Arctostaphylos alpina) mixed with lichens and herbaceous plants and low- and medium-shrub thickets (mainly willows, mountain alder [Alnus viridis], and dwarf birch) growing in open and closed stands.

Nest-placement habitat (n = 41 nests) as follows: tussock-shrub tundra (18), dwarf-shrub mat (15), low-shrub thickets (4), medium-shrub thickets (2), and sedge/dwarf-shrub bog (2). Young chicks found in dwarf-shrub meadows and low-shrub thickets on lower slopes; older (2–3 wk old) chicks frequent sedge/dwarf-shrub bogs and dwarf-shrub mats on upper slopes (Lanctot et. al Lanctot et al. 1995 Lanctot, R. B., Jr. Gill, R. E., T. L. Tibbitts, and C. M. Handel (1995). Brood amalgamation in the Bristle-thighed Curlew Numenius tahitiensis: process and function. Ibis 137:559–569. Close , BJM, REG, TLT). Newly fledged young move freely among all available habitats, with preference for dwarf-shrub meadows (primarily tussock-shrub tundra), dwarf-shrub mats, and sedge/dwarf-shrub bogs on upper slopes and ridges.

Habitat in Migration

Postbreeding birds on the Seward Peninsula use dwarf-shrub habitat along coastal lowlands (Kessel 1989 Kessel, B. (1989). Birds of the Seward Peninsula, Alaska: Their Biogeography, Seasonality and Natural History. University of Alaska Press, Fairbanks, AK, USA. Close ). Fall migrants on Yukon Delta use graminoid meadows (mixture of Carex rariflora, C. ramenskii, and Calamagrostis canadensis) and a mosaic of tundra/meadow habitat consisting of patches of black crowberry, lingonberry, and cloudberry (Rubus chamaemorus) interspersed with small graminoid meadows (TLT, REG). For birds staging on central Yukon Delta in Jun–Jul, flocks (n = 118 in 1988 and n = 138 in 1989) distributed those respective years in 58% and 78% tundra/meadow mosaic habitat, 22% and 23% graminoid meadows, and 18% and 0% exposed muddy margins of ponds; latter available only in years with very low rainfall (TLT, REG). Annual variation in standing crop of fruits of black crowberry and ericaceous shrubs appears major determinant of habitat use (REG).

Fall migrants on central Yukon Delta roost at night in shallow brackish ponds edged with marestail (Hippurus tetraphylla) and surrounded by vast wet-sedge meadows (TLT).

Habitat in Overwintering Range

No detailed study of habitat use on winter range. Frequents wide variety of habitats on islands, including tidal mudflats, marshy areas, edges of mangrove swamps and lagoons, reefs, saltpans, channels among islets, beaches, forb mats, airport runways, and open areas well away from shoreline (Gallagher 1960 Gallagher, M. D. (1960). Bird notes from Christmas Island, Pacific Ocean. Ibis 102 (4):489-502. Close ; Woodbury 1962 Woodbury, A. M. (1962). A review of the ecology of Eniwetok Atoll, Pacific Ocean. Univ. of Utah, Salt Lake City: Inst. Environ. Biol. Res. Close ; Fosberg 1966 Fosberg, F. R. (1966). Northern Marshall Islands land biota: birds. Atoll Research Bulletin 114. Close ; Bakus 1967 Bakus, G. J. (1967). Changes in the avifauna of Fanning Island, central Pacific, between 1924 and 1963. Condor 69:207-209. Close ; Holyoak Holyoak 1974a Holyoak, D. T. (1974a). Les oiseaux des isles des la Societe. Oiseau Rev. Fr. Ornithol. 44:1-184. Close , Holyoak 1975a Holyoak, D. T. (1975a). Les oiseaux des isles Marquises. Oiseau Rev. Fr. Ornithol. 45:207-234. Close , Holyoak 1980 Holyoak, D. T. (1980). Guide to Cook Islands birds. Wellington, New Zealand: Cook Islands Library and Mus. Soc. Close ; Lacan and Mougin 1974a Lacan, F. and J. L. Mougin. (1974a). Les oiseaux des Iles Gambier et de quelques de l'Archipel des Tuamotu (Ocean Pacifique). Oiseau Rev. Fr. Ornithol. 44:192-284. Close ; Muse and Muse 1982 Muse, C. and S. Muse. (1982). The birds and birdlore of Samoa. Walla Walla, WA: Pioneer Press. Close ; Holyoak and Thibault 1984 Holyoak, D. T., and J.-C. Thibault. (1984). Contribution à l’étude des oiseaux de Polynésie orientale. Mémoires du Muséum national d’histoire naturelle Serie A, Zoologie 127:1–209. Close ; Schubel and Steadman 1989 Schubel, S. E. and D. W. Steadman. (1989). More bird bones from Polynesian archeological sites on Henderson Island, Pitcairn Group, South Pacific. Atoll Research Bulletin 325. Close ). Curlews used 8 habitat types on Rangiroa Atoll in Tuamotu Archipelago. Most detected in saltpans (36%) and channels between islets (27%); fewer (4–13%) on ocean terraces, sand beaches, vegetated clearings, coral reefs, and beneath coconut (Cocos) trees (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 ). More common on lagoon shores than ocean beaches in 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 ). Found in herb mats, Tournefortia scrub, and beneath Pisonia and Cocos forest on Caroline Atoll (Kepler et al. 1994 Kepler, C. B., A. K. Kepler and D. H. Ellis. (1994). The natural history of Caroline Atoll, southern Line Islands. Part 2. Seabirds, other terrestrial animals, and conservation. Atoll Research Bulletin 398:1-61. Close ); open grassy areas, vegetated dunes, and wetlands on main Hawaiian Is. (Paton and Scott 1985 Paton, P. W. C. and J. M. Scott. (1985). Waterbirds of Hawaii Island. 'Elepaio 45:69-76. Close , JSM); and on beaches and at coral ledges at shoreline but more often in grass- and forb-dominated interior portions of Northwestern Hawaiian Is. (Woodward 1972b Woodward, P. W. (1972b). The natural history of Kure Atoll, Northwestern Hawaiian Islands. Atoll Research Bulletin 164. Close , Ely and Clapp 1973 Ely, C. A. and R. B. Clapp. (1973). The natural history of Laysan Island Northwestern Hawaiian Islands. Atoll Research Bulletin 171. Close , Amerson et al. 1974 Amerson, A. B., Jr, R. C. Clapp and III W. O. Wirtz. (1974). The natural history of Pearl and Hermes Reef, Northwestern Hawaiian Islands. Atoll Research Bulletin 174. Close , Clapp and Wirtz Clapp and Wirtz II 1975 Clapp, R. B., and W. O. Wirtz II (1975). The natural history of Lisianski Island, northwestern Hawaiian Islands. Atoll Research Bulletin 186. Close , JSM). During systematic censuses on Laysan I. in fall 1988, 68% of sightings (n = 2,521) inland in beach morning glory (Ipomoea pes-caprae), native bunchgrass (Eragrostis variabilis), or mix of both; only 1% on beaches (JSM).