Distinguishing Characteristics

Medium-sized, relatively long-billed calidridine sandpiper (29 cm in length, 90–131 g mass). In breeding (Alternate) plumage, crown and upperparts variegated with brown, black, and buff markings, while most underparts rufous with dark barring tipped white in fresh plumage; underparts quickly become darker and more uniform with wear (Pitelka 1961, Wilds 1990). In Basic plumage, mainly drab gray, but underparts paler, with whitish belly contrasting with darker, unspotted breast. In all plumages shows short whitish supercilium and dark loral stripe; tail barred black and white, with distinctive white wedge on rump from tail to middle of back; and whitish trailing edges on secondaries in flight. Juvenal plumage similar to breeding adult but paler, with unmarked tertials margined with dark cinnamon (appear duller-colored and darker above because of more restricted pale edging and internal markings of dorsal feathers); grayer head, neck, and upper breast, with upperparts fringed chestnut rather than buffy brown; and uniformly gray breast sharply demarcated from pale rufous lower breast and belly (Aldrich 1948, Chandler 1998). Sexes alike but female generally heavier (White and Mitchell 1990), with longer wings and bill than males (Pitelka 1950).

Slightly decurved bill black but becoming olive at base, widened laterally near the ridged tip; iris brown; legs and feet yellowish olive.

Difficult to distinguish from Short-billed Dowitcher, although keek call given by Long- billed is distinct from tu-tu-tu of Short-billed. Long-billed generally calls more (Paulson 1993). Structure of dowitchers useful for comparisons. Profile godwit-like due to longer bill and longer tibia compared to shorter, more snipe-like bill and shorter tibia of Short-billed (Jaramillo and Henshaw 1995). Bill often twice head length (Rowan 1932, Cramp and Simmons 1983, Wilds and Newlon 1983), especially in females, but great overlap with Short-billed, especially in males. For individuals collected in California (Pitelka 1950), mean (mm) culmen length for Long-billed female 71.7 ± 4.03 SD (n = 65), for Long-billed male 61.2 ± 2.39 (n = 148), for Short-billed female 62.0 ± 2.33 (n = 87), and for Short-billed male 56.8 ± 2.12 (n = 116). Very long bills often have flattened, slightly S-shaped curve (S. Howell pers. comm.).

Primaries do not extend beyond tail in perched Long-billed Dowitcher (typically fall 1 mm short of the tip), but longer wings typically extend 2–3 mm beyond tail in Short-billed (Rowan 1932, Pitelka 1950, Nisbet 1961, Chandler 1998, Jaramillo et al. 1991, but see Wallace 1980), especially on the Pacific coast where L. g. caurinus is the most common Short-billed subspecies (see Paulson 1993). In flight, feet of Long-billed also appear to extend more past the tail than in Short-billed (Chandler 1998, S. Howell pers. comm.).

In all plumages, Long-billed generally darker in appearance than Short-billed (S. Howell pers. comm.). Tail feathers more heavily barred than Short-billed; black bars generally wider than paler bars. However, barring is quite variable and overlaps with Short-billed, especially L. g. griseus (Paulson 1993), and should be used only as a secondary key (Jaramillo and Henshaw 1995). In Alternate plumage, Long-billed underparts deep brownish rufous over entire abdomen, sides of breast dusky and more barred than spotted, although both species have barred flanks edged in white, producing a “frosty” appearance until mid-May (Newlon and Kent 1980, Jaramillo et al. 1991). Distinct feather characteristics generally decrease as Alternate plumages become more worn (Jaramillo et al. 1991, Jaramillo and Henshaw 1995). Center of belly never spotted in Long-billed (Orr 1940, Paulson 1993), although some L. g. griseus and L. g. hendersoni lack belly spots also. In fresh plumage, bold, double-edged white tips on scapulars and tertials of Long-billed distinct in some individuals compared to white to dull gray tips in Short-billed (Jaramillo and Henshaw 1995), with exception of some bright L. g. griseus (Chandler 1998). Much variation in barring, but Long-billed primarily or entirely barred on sides and flanks, while Short-billed with spot-like bars or more spots than bars (Newlon and Kent 1980, Jaramillo et al. 1991). In Basic plumage, species very difficult to separate. Darker overall appearance of Long-billed and sharp delineation between gray upper breast and white lower breast are useful characteristics, as well as lack of fine spots often present on breast of Short-billed (Chandler 1998). Juvenile Long-billed has tertials and scapulars with pale, narrow buffy edges and no or faint internal markings, whereas Short-billed has strongly marked internal bars and loops and broad buff edging, especially on tertials (Wilds and Newlon 1983, Wilds 1990, Paulson 1993). In summary, call of Long-billed versus Short-billed best distinguishing characteristic. Plumage characteristics of juveniles and fresh Alternate plumage adults allow for positive identification of most individuals, while distinguishing worn Alternate-plumage dowitchers, and especially those in Basic plumage, is difficult without measurements or calls.

Similar in appearance to Asian Dowitcher (L. semipalmatus) and Stilt Sandpiper (Calidris himantopus), but Asian Dowitcher in Alternate plumage is larger, with chestnut-rufous face, neck, and breast; in Basic plumage, is grayer in appearance without a patch of white on the back, with wider, pale trailing edge to the wing, blunt-tipped black bill, and black legs (Chandler 1998). Stilt Sandpiper in Basic plumage is more slender, with a shorter, thinner bill, longer neck, greenish legs, white supercilium with eye-stripe, and square white patch on lower rump and uppertail-coverts. In Basic plumage, Bar-tailed Godwit (Limosa lapponica) is taller, whiter, with dark legs, base of bill pinkish or yellowish.