Identification

Large, long-legged shorebird with very long, tapering upturned bill. Overall length 37–39 cm, including bill 8–12 cm; mass 200–720 g. Wing long with uniform pattern, tail barred, legs greenish gray, bill black towards tip and pink towards base (Hayman et al. 1986, Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close , Higgins and Davies 1996 Higgins, P. J., and S. J. J. F. Davies (editors). (1996). Handbook of Australian, New Zealand & Antarctic birds. Volume 3. Melbourne: Oxford University Press. Close ).

Molt complex with marked seasonal variation in plumages allowing separation of at least 3 age classes (Barter and Wang 1990 Barter, M. and T. H. Wang. (1990). Can waders fly non-stop from Australia to China? Stilt 17:36-39. Close ). In breeding (Definitive Alternate) plumage, males dark brown above with rufous-brown to buff fringes and notches on many feathers, plumage wholly rufous to rich chestnut below with some white on lower belly. Wing brown with inconspicuous wing stripe; underside of wing dark gray in North American populations, but white underwing in other populations; virtually no barring on underparts. Rump and uppertail-coverts white in nominate, but heavily barred brown in baueri; race <em>menzbieri</em> intermediate in plumage between nominate and baueri, with lower back and rump fairly strongly barred; bill and tarsus shortest in nominate; baueri has relatively long wings and tail.

Female larger than male (see Measurements) with longer bill and duller plumage; upperparts dull cinnamon or buff. Underparts vary from pale chestnut or cinnamon to just tinged pink-buff to cream. Nonbreeding (Definitive Basic) plumage of both sexes plain gray-brown above with darker brown feather centers giving overall striped look; mostly white beneath but breast grayer with brown streaks (Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close ).

Juveniles similar to non-breeding adult (see Appearance, below) but with warm pale buff wash and fine streaks on foreneck, breast , and flanks, contrasting with whitish rest of underbody. Fine pattern of contrasting light and dark of dorsal feathering (especially scapulars and tertials) gives “speckled” appearance at least into Nov (REG). Non-breeding adult has upperparts pale grey-brown, partly edged whitish; breast turns grey, with fine dark streaking; underparts white.

Similar Species

In North America, likely to be confused only with larger Marbled Godwit (L. fedoa) and slightly smaller Hudsonian Godwit (L. haemastica). Following differences between Marbled and Bar-tailed godwits primarily from Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close : (1) Bar-tailed Godwit smaller with shorter legs and bill (these difficult to discern without direct comparison); (2) wings project about 25 mm beyond tail in resting birds (versus <13 mm in Marbled Godwit); (3) in flight, wings brownish with faint wing-stripe (versus very reddish wings of Marbled Godwit); (4) overall color of Bar-tailed Godwit variable (from chestnut in males to cinnamon to mixed rufous and white or entirely whitish below in some females) compared to uniformly cinnamon in Marbled Godwit; (5) tertials always barred in Marbled Godwit versus some Bar-tailed Godwits with plain or striped tertials; (6) in Basic plumage, Bar-tailed Godwit is plain gray-brown above and whitish below (versus very reddish in Marbled Godwit in all plumages); and (7) juvenile Bar-tailed Godwit 2-toned and paler beneath, with buffy breast and whitish belly (versus entirely buffy cinnamon in Marbled Godwit); tail and rump whitish and barred in Bar-tailed Godwit (versus reddish and barred in Marbled Godwit); supercilium pale with dark eye-stripe extending conspicuously behind eye in Bar-tailed Godwit (versus fading out quickly in Marbled Godwit); and primaries whitish on inner webs in Bar-tailed Godwit (versus reddish in Marbled Godwit).

Hudsonian Godwit slightly smaller than Bar-tailed Godwit, with distinctive plumage pattern showing white-based, black-tipped tail, conspicuous wing-stripes, and blackish underwings during flight. Differs from Bar-tailed Godwit in Alternate plumage by being either fairly heavily barred beneath (females) or very dark, white-spotted above (males). Basic-plumaged birds are plain backed (juveniles faintly scalloped) compared to heavily patterned with stripes and bars in Bar-tailed Godwit. Plainest nonbreeding Bar-tailed Godwits can be almost as plain as Hudsonian Godwits, but former usually have at least faint stripes on upperparts and breast.

Could be confused with Black-tailed Godwit (L. limosa) and Asiatic Dowitcher (Limnodromus semipalmatus) on breeding grounds (differences explained in Higgins and Davies 1996 Higgins, P. J., and S. J. J. F. Davies (editors). (1996). Handbook of Australian, New Zealand & Antarctic birds. Volume 3. Melbourne: Oxford University Press. Close ). Only on w. Aleutian and Bering Sea islands during spring and early summer are Bar-tailed and Black-tailed godwits likely to co-occur (Kessel and Gibson 1978 Kessel, B., and D. Gibson (1978). Status and distribution of Alaska birds. Studies in Avian Biology 1:1–100. Close , Gibson and Kessel 1997a Gibson, D. D., and B. Kessel (1997). Inventory of the species and subspecies of Alaska birds. Western Birds 28:45–95. Close , S. Heinl unpubl.). Photographs of various age- and sex-specific plumages of Bar-tailed Godwits appear in Pringle 1987 Pringle, J. D. (1987). The shorebirds of Australia: the national photographic index of Australian wildlife. North Ryde, Australia: Angus and Robertson Publ. Close , Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close , Rosair and Cottridge 1995 Rosair, D., and D. Cottridge (1995). Hamlyn Photographic Guide to the Waders of the World. Hamlyn Limited, Melbourne, Australia. Close , and Thurston 1996 Thurston, H. (1996). The nature of shorebirds: nomads of the wetlands. Vancouver, BC: Greystone Books. Close .