Plumages, Molts, and Structure

Hudsonian Godwits have 10 functional primaries, 16-18 secondaries (including 4 tertials), and 12 rectrices; godwits are diastataxic (see Bostwick and Brady 2002) indicating that a secondary has been lost evolutionarily between what we now term s4 and s5. Little or no geographic variation in appearance (see Systematics: Geographic Variation) or geographic or sex-specific variation in molt strategies reported.

Following based primarily on detailed plumage descriptions in Ridgway (1919), Bent (Bent 1927 Bent, A. C. (1927). Life histories of North American shorebirds, Part 1. U.S. Nat. Mus. Bull. 142. Close ), Roberts (1955), Palmer (1967b), Oberholser (1974), Johnsgard (1981), Cramp and Simmons (1983), Hayman et al. 1986, Rosair and Cottridge (1995), Paulson (Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close , 2005), Higgins and Davies (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 , especially), and O'Brien et al. (2006); other literature noted explicitly. See Prater et al. (Prater et al. 1977 Prater, A. J., J. H. Marchant, and J. Vuirinen (1977). Guide to the Identification and Aging of Holarctic Waders. British Trust for Ornithology, Tring, United Kingdom. Close ) and Pyle (2008) for specific age-related criteria. Capitalized color names follow Smithe (Smithe 1975 Smithe, F. B. (1975). Naturalist's Color Guide. American Museum of Natural History, New York, NY, USA. Close ); corresponding number codes are given with first mention of each color name unless 2 numbered colors have the same name, in which case given at every mention; other color names are not based on systematic comparisons to color charts. Plumage color scores of Definitive plumages from birds collected in Churchill, Alaska, or s. South America; those for Juvenile plumage primarily from 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 ; note that for Definitive plumages color scores differ slightly, but consistently, between that account and this one. Sexes show similar appearances in Juvenile, Formative, and Definitive plumages but differ in First (sometimes) and Definitive Alternate Plumages. Definitive Plumages typically assumed at Second Basic and Second Alternate Plumages.

Natal Down

Present Jul-Aug. Hatchlings covered with down. Ground color may differ widely between individuals from whitish to dark gray, even within one brood (JK); described as buff, pale pinkish buff, and pinkish gray, darker on lower neck, sides of breast and thighs, light on head. Squarish crown-patch solidly dark surrounded by a few smaller patches including one on either corner at rear; narrow dark line from crown-patch to base of bill, and 2 others from bill to anterior corner of eyes; another dark line usually runs from crown-patch to markings on back; intense dark, almost black, markings on back form diamond shape, somewhat variable but exhibiting consistent patterns, with pale center between wings; brighter highlights to upperparts orange-red in color: ranging Tawny Brown (38) to Cinnamon (39); additional dark areas on wings, sides, and back of body; upper throat and belly grayish white (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close , Jehl 1968b Jehl, J. R., Jr. (1968). Relationships in the Charadrii (shorebirds): a taxonomic study based on color patterns of the downy young. Memoirs of the San Diego Society of Natural History 3. Close , Baicich and Harrison 1997 Baicich, P. J., and C. Harrison (1997). A Guide to the Nests, Eggs, and Nestlings of North American Birds. 2nd edition. Academic Press, San Diego, California, USA. Close ).

Juvenile (First Basic) Plumage

Present Jul-Sep/Nov. Sexes alike. Crown covered with dark feathers, with pale Buff (124) edges creating finely streaked appearance; dark crown contrasts with white supercilia to form a cap. Supercilium broader in front of eye than behind; lores and feathering immediately behind eye Sepia (219); chin white; nape and remainder of face Light Drab (119C). Mantle and scapulars Dark Drab (119B) to Light Drab, with Sepia (219) streaks along shaft and subterminal bar; second bar on longest scapulars. When fresh, these feathers fringed with Buff; as feathers wear, mantle appears increasingly dark due to central “anchor marks” becoming more exposed. Lower back and rump dark; uppertail coverts white except caudal row (which overlay tail) dark. Caudal upperparts either white feathers creating broad contrasting white band; coloration similar to Definitive Basic. Neck and upper breast Light Drab, becoming paler Drab-Gray (119D) toward belly. Feathers on flanks and sides of breast with dark streaks along shaft, becoming buff and increasingly pale toward tail, with off-white belly, vent and undertail coverts; sides of vent have small dark streaks.

Rectrices very dark with white bases, especially extensive on outer webs of outer rectrices (r6), which have indistinct border with dark tip (Pyle 2008); extreme feather tips Buff when fresh. Remiges, primary coverts, and alula also very dark; bases to secondaries and innermost primaries (p1 to p5/p6) and tips to inner greater primary coverts white, forming pale wing-stripe; white shaft streaks of primaries also contribute to wing patterning; lesser primary coverts with narrow white fringe. Tertials largely Sepia (219) with large Buff notches, in some cases forming uneven bars toward tip; when very worn, predominant color Dark Drab to Hair Brown (119A), darker along shaft (CSE). Colors of these wing feathers similar to those of Definitive Basic Plumage but quality less substantial, likely because of fewer barbules. Marginal lesser coverts similar to mantle feathers, though darker: Sepia (219) with Buff fringes. Lesser, median, and greater secondary coverts predominantly Light Drab. Lesser and median coverts fringed white; greaters edged and tipped with white, adding to wing-stripe; differ from coverts of Definitive Basic Plumage by having indistinct, dusky, anchor-shaped patterns when fresh (Pyle 2008). Under wing coverts and axillaries predominantly dark, coloration similar to Definitive Basic plumage.

Formative Plumage

"First Basic" or "Basic I" plumage of previous authors. Present Oct-Mar/Aug. Formative body feathers, increasingly mixed with juvenile head, upperpart, and underpart feathers in Oct-Jan, similar to those of Definitive Basic Plumage (see below). Formative Plumage further distinguished from older individuals by molt limits among secondary coverts and tertials between fresher replaced formative feathers and worn (extremely so by Mar-Aug) juvenile feathers; retained juvenile outer primaries and rectrices narrower and more abraded at tips, extremely so by Mar-Aug.

First Alternate Plumage

Present Mar-Sep. Similar to Formative Plumage but with scattered replaced body feathers, scapulars, and wing coverts, often showing patterns similar to or in between those of both Formative and Definitive Alternate Plumages, depending on timing of replacement. Fewer feathers replaced, on average, than in Definitive Alternate Plumage. Some individuals may show sex-specific differences as in Definitive Alternate Plumage whereas others (some males and most females) probably not distinguishable by plumage characters alone. See Formative Plumage for flight-feathers characters distinguishing First Alternate from Definitive Alternate Plumages.

Definitive Basic Plumage

Present Sep-Mar. Sexes largely similar in plumage (see below for possible average differences). Head and neck fairly uniform, Dark Drab to Grayish Horn Color (91), slightly darker on crown, paler on nape, ear coverts, face, and neck. Supercilium, chin, and upper throat much paler, Drab-Gray to white. Mantle, scapulars, and back uniform and slightly darker than neck: Olive-Brown (28), Dark Drab, Hair Brown. Lower back and rump dark, Hair Brown to Dark Drab, approaching Sepia (219) toward tips of feathers nearest the tail. Based on small sample, rump feathers slightly paler on females than males, more Dark Drab to Dark Brownish Olive (129) toward tips. Rear portions of upperparts (caudal to tips of tertials) white. On males, outer white feathers barred with Sepia or Hair Brown; central feathers have single subterminal bar; based on small sample, such barring apparently lacking, or at least reduced, on females. Distal-most row of uppertail coverts which overlay tail are Sepia (199) approaching Jet Black (89) on males, with narrow white tips on innermost feathers and outermost 2–3 becoming largely white. Transition on upper breast from Dark Drab and Grayish Horn Color of neck to paler underparts, which are a dirty off-white, with hints of Drab-Gray. Flanks darker, similar to neck color. Paler on belly. Vent and undertail coverts off-white and unmarked.

Tail feathers predominantly Sepia (119), slightly paler than dark uppertail coverts; paler toward tip, variable Light Drab to Drab-Gray. Rectrices with variable amount of white at base; white visible beyond uppertail coverts on outermost 2–3 feathers; outer rectrices (r6) with less white and more distinct dark tip than in juvenile feathers (Pyle 2008); fringes of rectrices can have narrow white margin when fresh, varying in breadth from a few mm to almost 1 cm. Tail slightly notched. Remiges very dark, becoming slightly paler proximally. Primaries Sepia (119), with variable amount of white toward the base and white tips on the inner primaries; outer secondaries Sepia (119) to Hair Brown; inner primaries Hair Brown to Dark Brownish Olive and distinctly paler than primaries, even approaching Dark Drab toward the tip; secondaries white at base, contributing to pale wing-stripe; white most extensive on outermost feathers. Tertials uniform Dark Brownish Olive, Olive Brown, or Dark Drab.

Primary-coverts and alula Sepia (119) with white tips to innermost greater primary coverts. Other upperwing coverts largely uniform and similar in color to back. Lesser and median coverts Hair Brown to Dark Drab with Sepia (119) shaft streaks. Marginal lesser coverts darker, approaching Sepia (119). Overall these feather tracts appear slightly paler on female than male, ranging from Hair Brown to Light Drab with darker shaft streaks. Darkest lesser coverts on female similar to darkest coverts on male, but in males, most feathers are at the dark end of the range, whereas in females, more feathers are pale. Greater secondary coverts slightly lighter (Dark Drab to Light Drab), with pale edge to outer web and tip. Outermost greater coverts with white tips, broadest on feathers nearer the primaries, which adds to white bases of remiges to form white wing stripe.

Underside of remiges somewhat reflective, Dark Drab. Underwing axillaries, subhumerals, and lesser and median secondary coverts predominantly Sepia (119) and Dark Brownish Olive, ranging to Hair Brown; not black. Lesser underwing primary coverts Hair Brown with broad white tips. Greater underwing primary coverts reflective Olive-Brown. Greater underwing secondary coverts largely white with irregular Hair Brown to Dark Drab bars, more extensive on inner web of some feathers.

Definitive Basic Plumage distinguished from Formative Plumage by uniform basic secondary coverts and tertials, the secondary coverts without indistinct dusky anchor-shaped pattern, and basic outer primaries and rectrices broader, fresher at tips, and less bleached.

Definitive Alternate Plumage

Present Mar-Aug. Sexes differ, differences largely due to extent of different colors on individual alternate feathers, rather than different molt extent; hence, sexes discussed together, with differences noted where relevant. Many differences not absolute, and there is much individual variation within sexes. Crown-feathers with Sepia (119) centers and Drab-Gray edges, the Sepia centers averaging smaller on females than on males, creating impression of a pale crown with dark streaks on females and a dark crown with fine pale streaks on males. Face and ear coverts predominantly off-white to Drab-Gray, with very narrow streaks in centers of feathers giving a finely streaked appearance; streaks paler on females (Dark Drab) than on males (Sepia [119]). Supercilium (broad in front of eye but diffuse behind eye) pale off-white to Drab-Gray, almost pure white in some individuals. Lores predominantly Sepia (119) on males, less extensive or distinct on females.

Nape feathers with similar color pattern to crown, although Sepia (119) centers are narrower creating a paler overall appearance; on males crown appears distinctly darker than nape whereas on females some feathers have paler centers, ranging from Sepia (119) to Dark Drab, as on face. Feathers on neck of females similar to those on face, predominantly off-white to Drab-Gray with narrow Sepia (119) streaks along shaft whereas those of males more brightly colored with rufous hues; on some males, this coloration is very extensive and reaches chin and face. Neck feathers also have fairly narrow Sepia (119) centers but remainder of feather varies from Brussels Brown (121B) to Verona Brown (223B), paler in some, with True Cinnamon (139) to Robin Rufous (340). In others, rufous color is more restricted, and feathers have off-white edges, creating paler, less bright appearance overall. On all individuals, feathering on cheeks and throat is paler, with more off-white, than on neck. Chin with feathering whitish to completely white in some individuals, variable in extent.

Mantle feathers and scapulars of both sexes with dark centers and pale spots along edges, the spots and pale tips larger on females, creating an overall appearance of paler plumage with dark mottling; males appear dark with white spots. On females, feather centers are largely Sepia (119), but approach Dark Brownish Olive or even Dark Drab toward base. Spots and pale tips are predominantly Light Drab to Drab-Gray, with hints of Sayal Brown (223C) or True Cinnamon in places. In general, though, females lack bright rufous colors and bright white spots. On males, feather centers predominantly Sepia (119), approaching Hair Brown toward the base. Spots less uniformly colored than on females, varying from almost white to True Cinnamon and Sayal Brown, approaching Robin Rufous on brightest feathers. Spots toward feather tip merge together through wear. Rump, uppertail coverts, and lower back similar to Definitive Basic plumage.

Basic remiges, rectrices, primary coverts, and many other upperwing coverts retained, similar to Definitive Basic plumage but becoming slightly paler through spring and summer with wear. Replaced median coverts on upperwing of males Sepia (119) along shaft with variable Brussels Brown to Verona Brown notches and white to Drab-Gray internal markings. On females, these feathers more uniform Dark Drab to Light Drab. Tertials patterned in a similar manner to scapulars and mantle feathers and predominantly Sepia (119) in both sexes, the males with white spots along margins and at tip, quite worn in some individuals; brightest males have orange-red tones of back feathers on some of these tertial spots. Tertials of females with Light Drab to Drab-Gray notches and a white tip, creating more subtle pattern than on males.

Base of neck in both sexes with a transition from feathers with fine vertical streaks to feathers with horizontal barring and increasing amounts of rufous coloring; brighter coloration much more extensive on males than on females. On males, feathers of breast, belly, and flanks predominantly Brussels Brown to Verona Brown, but somewhat darker than feathers on neck, each feather with 3–6 narrow irregular Sepia (119) bars, spaced 5–10 mm apart along length. Bars about 1 mm wide on smaller feathers, slightly broader on longer flank-feathers, the last bar within a couple of millimeters of the feather tip; many feathers tipped with off-white as possibly affected by wear. These feathers also off-white at base and, on some, a very narrow dark streak bleeds out of each bar along the feather shaft. On females, underparts are more mottled, the feathers predominantly off-white to Drab-Gray with Sepia (219) to Hair Brown bars. Bars broader on flanks, especially toward tail, where Sepia may extend along feather shaft between bars. Feathers all pale at base and tip, but most have variable amounts of Robin Rufous to True Cinnamon, primarily between 2 bars closest to feather tip, occasionally also closer toward calamus, especially on longer flank-feathers. Barring and rufous coloration reduced on rear belly feathers and vent of females; feathers much whiter than on upper belly or on male.

Undertail coverts with similar patterning to other feathers of underparts except that Sepia bars are broader (3–4 mm on males, narrower on many females) and darker (approaching Jet Black), and intervening bars are more extensively white or off-white; calamus side of each dark bar Minimal Brussels Brown to Verona Brown, especially on males. White bars similar in breadth or slightly broader than Sepia bars. Undertail coverts extend almost to tail tip, and underside of tail appears barred. Underwing coverts and axillaries as in Definitive Basic plumage.

See Definitive Basic Plumage for wing-covert and flight-feather criteria separating First Alternate Plumage from Definitive Alternate Plumage; differences become more distinct due to advanced wear and bleaching of juvenile feathers in First Alternate Plumage.

General

Molt and plumage terminology follows Humphrey and Parkes (1959) as modified by Howell et al. (2003, 2004). Hudsonian Godwit exhibits a Complex Alternate Strategy (cf. Howell et al. 2003, Howell 2010), including complete prebasic molts, a partial-to-incomplete preformative molt, and limited-to-partial prealternate molts in both first and definitive cycles (Stone 1900, Bent 1927 Bent, A. C. (1927). Life histories of North American shorebirds, Part 1. U.S. Nat. Mus. Bull. 142. Close , Palmer 1967a, Oberholser 1974, Prater et al. 1977 Prater, A. J., J. H. Marchant, and J. Vuirinen (1977). Guide to the Identification and Aging of Holarctic Waders. British Trust for Ornithology, Tring, United Kingdom. Close , Cramp and Simmons 1983, 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 , Pyle 2008; Fig. 3). Molts follow a "Southern Hemisphere Strategy" as defined by Pyle (2008), which generally includes protracted and incomplete preformative molts and protracted prebasic molts. Definitive molt cycle commences with the Second or Third Prebasic Molt.

Prejuvenile (First Prebasic) Molt

Complete, Jun-Jul, on or near the breeding territory. Little information on timing or duration (see Breeding: Young Birds, Growth and Development). See Figure 5 for wing chord lengths by age, indicating growth rate of outer primaries.

Preformative Molt

"First prebasic" or "Prebasic I" molt of previous authors. Partial to incomplete, Oct/Dec-Jan/Jun, on non-breeding grounds. Virtually all migrant 1st-cycle birds seen in the U.S. retain pristine juvenile plumage, or maybe show just a feather or two replaced, suggesting that most/all molt occurs on South American winter grounds. Variation in molt timing likely tied to variation in migration timing. Extent little known and apparently variable (Pyle 2008); likely includes most-to-all body feathers and some-to-most secondary coverts, tertials, and rectrices. Replacement of these feathers may occur primarily in Oct-Dec. Other godwits wintering in the Southern Hemisphere can also replace inner or outer primaries and molt all secondary coverts, tertials, and rectrices, molt extending through winter and even into first summer, and overlapping some or all of First Prealternate Molt. Study needed on this in Hudsonian Godwit. Many first-cycle individuals may spend the first summer in South America and few specimens in formative or first-alternate plumage available for examination.

First Prealternate Molt

Limited (occasionally partial, possibly occasionally absent), Mar-May, on non-breeding grounds. Essentially unknown (see Preformative Molt). In some individuals may be as extensive as Definitive Prealternate Molt, and it may average less extensive in individuals that remain in the Southern Hemisphere for the first summer than in those that migrate north. Typically may include variable patches of feathers on upperparts and underparts and up to a few scapulars, secondary coverts, and tertials.

Second Prebasic Molt

Complete, May-Nov, occurring on non-breeding grounds in most birds but may begin on summer grounds or stop-over sites and suspend for southward autumn migration in individuals that migrate north for first summer. Similar in sequence to Definitive Prebasic Molt but occurs earlier in year due to lack of constraints related to breeding.

Definitive Prebasic Molt

Complete, Jul-Jan/Mar, often commencing on summer grounds or stopover sites, usually completing on winter grounds. Primaries replaced distally (p1 to p10), secondaries replaced proximally from s1 and s5 and distally from the tertials, and rectrices probably replaced distally (r1 to r6) on each side of tail, with some variation in rectrix sequence possible. Can begin in Jul, immediately after breeding, with body feathers; brood patch largely filled in by last third of Jul (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close ). Body molt continues during migration period and is often largely complete by Aug or Sep, with some replacement through Nov (Morrison 1984c Morrison, R. I. G. (1984). Migration system of some New World shorebirds. In Behavior of Marine Animals. Volume 6. Shorebirds: Migration and Foraging Behavior (J. Burger and B. L. Olla, Editors). Plenum Press, New York, NY, USA. pp. 125–202. Close , Wright 1987 Wright, G. (1987). Hudsonian Godwit in Devon. British Birds 80:492-494. Close , Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close , Seppi 1995 Seppi, B. E. (1995). Hudsonian Godwit migration at Carter Spit, Alaska. Western Birds 26:167. Close ); occasionally body molt completed on winter grounds. Head and neck molted first, underparts later, with last replacement usually occurring toward the rear. Tertials, wing coverts, some scapulars and mantle feathers potentially retained until late in fall. Flight-feather molt poorly known, usually delayed until after southbound migration. Non-breeders staying in South America during the boreal summer, potentially including second-cycle and older birds, appear to go through a complete molt between May and Nov (Pyle 2008).

Definitive Prealternate Molt

Partial, Feb-May, commencing on near non-breeding grounds and sometimes/often completing at stopover-sites, possibly occasionally finishing on breeding grounds. Usually includes most body feathers, up to 20% of secondary coverts (scattered feathers, often those located in medial portion of covert tracts), 1-5 tertials, and occasionally 1-2 central rectrices. Outer greater coverts of some individuals replaced (CSE). Begins Jan-early Mar, before leaving nonbreeding grounds in at least some individuals (e.g., Baker et al. 1995a Baker, A. J., R. E. Manriguez, L. G. Benegas, D. Blanco and O. Borowik. (1995a). Red Knots Calidris canutus rufa at their farthest south: an international Expedition to Tierra del Fuego, Argentina, in February 1995. Wader Study Group Bulletin 79:103-108. Close ), and continues while on migration. Can proceed quickly; one replaced most body feathers within 22 d and up to 60% of others in s. Brazil had attained Alternate plumage by mid-Mar; molt may be largely completed before northbound migration begins (Wetmore 1926c Wetmore, A. (1926). Observations on the birds of Argentina, Paraguay, Uruguay, and Chile. United States National Museum Bulletin 133:1–448. Close , Lara Resende 1988 Lara Resende, S. de M. (1988). Nonbreeding strategies of migratory birds at Lagoa do Peixe, Rio Grande do Sul, Brazil. Master's Thesis, Cornell Univ., Ithaca, NY. Close , Cox 1990 Cox, J. B. (1990). Observations of a Hudsonian Godwit in South America. S. Aust. Ornithol. 31:48-51. Close ). Molt largely complete upon arrival in s. United States from mid-Apr into May (Oring and Davis 1966 Oring, L. W. and W. M. Davis. (1966). Shorebird migration at Norman, Oklahoma: 1961-63. Wilson Bulletin 78:166-174. Close , Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close ), although individuals retaining much Basic plumage are seen during spring migration in North America (e.g., Dinsmore et al. 1984 Dinsmore, J. J., T. A. Kent, D. Koening, P. C. Petersen, and D. Rossa (1984). Iowa Birds. Iowa State University Press, Ames, IA, USA. Close , Eckert 1999a Eckert, C. D. (1999a). A notable movement of godwits in the Yukon, spring 1999. Birder's Journal 8:149-150. Close ); these possibly first-cycle birds undergoing less-extensive First Prealternate Molt. Little information on relative timing of different feather tracts.

Bill And Gape

Colors determined largely from photographs (see 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 ) and may suffer from color distortion. Bill Dark Neutral Gray (83) to Blackish Neutral Gray (82) toward tip, paler toward base. Extent and color of pale base varies seasonally and with sex. During nonbreeding season, proximal 30–50% of bill is pale grayish-pink, Pink (7), or Spinel Pink (108C) in both sexes. On some individuals, dark color of bill tip extends up culmen and upper tomia toward face. When breeding, pale area increases to occupy 50–60% of bill. During courtship period, base of bill becomes Spectrum Orange (17) in males, fading rapidly thereafter to the purplish pink color of breeding females (Sutton 1968b Sutton, G. M. (1968b). Sexual dimorphism in the Hudsonian Godwit. Wilson Bulletin 80:251-252. Close ); after Jun, all with dull pinkish at base of bill (Sutton 1968b Sutton, G. M. (1968b). Sexual dimorphism in the Hudsonian Godwit. Wilson Bulletin 80:251-252. Close ), presumably the same color held during the nonbreeding season. A trace of orange reported to persist on some individuals through Aug (Hope and Shortt 1944 Hope, C. E. and T. M. Shortt. (1944). Southward migration of adult shorebirds on the west coast of James Bay, Ontario. Auk 61 (4):572-576. Close ). Dark lines ex-tending toward face on upper bill may fade to Light Drab or Drab-Gray, or disappear, as bill base brightens. Inside of gape reddish on males, orange on females, and gray on chicks (JK).

Iris

Sepia (119), also reported as black-brown, dark brown, and hazel.

Legs And Feet

Based on photos: Dark Neutral Gray to Blackish Neutral Gray. Specimens collected on breeding grounds reported to have dusky-brown feet and legs, with the soles of the feet paler and greenish gray (Hope and Shortt 1944 Hope, C. E. and T. M. Shortt. (1944). Southward migration of adult shorebirds on the west coast of James Bay, Ontario. Auk 61 (4):572-576. Close ). Legs of chicks slate blue (J. R. Jehl, Jr., pers. comm.).

Linear Measurements

Appendix 1. Females significantly larger than males; adults' wings also significantly longer than those of first-year Hudsonian Godwits, when comparisons are made separately for each sex; adult females have longer bills than first-year females (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 ). Thirteen females and 14 males (sexed by examination of internal organs) could all be accurately sexed using bill length, 93% using wing length, and 89% using tarsus length (Alexander and Gratto-Trevor 1997 Alexander, S. A., and C. Gratto-Trevor (1997). Shorebird migration and staging at a large prairie lake and wetland complex: The Quill Lakes, Saskatchewan. Canadian Wildlife Service Occasional Papers no. 97. Environment Canada, Ottawa, Ontario, Canada. Close ).

Two populations, Susitna Flats and Churchill, have been studied in depth. See Appendix I. See also Breeding: young birds, above.

Mass

Females heavier than males: In Churchill, MB, 255.0 g (n = 36) and 215.0 g (n=24), respectively, for birds caught during breeding season. In Susitna Flats, AK, during breeding season, 267.0 g (n = 29 females) and 228.0 g (n = 23 males).

Migrants at a fall staging site in Saskatchewan: 335.9 g (range 209–436); higher mass presumably due to fattening for long migratory flights (see Migration: control and physiology Alexander and Gratto-Trevor 1997 Alexander, S. A., and C. Gratto-Trevor (1997). Shorebird migration and staging at a large prairie lake and wetland complex: The Quill Lakes, Saskatchewan. Canadian Wildlife Service Occasional Papers no. 97. Environment Canada, Ottawa, Ontario, Canada. Close ).

Mean for unsexed individuals caught in s. South America (Tierra del Fuego) in February was 240.2 g ± 24.0 SD (range 210–296, n = 34; T. Piersma, A. J. Baker, and C. D. T. Minton pers. comm.); based on bill lengths, this sample appeared to be male-biased.