Appearance

Considerable variation in plumage color within many subspecies; described as color phases or morphs; not related to age, sex, or adventitious coloring (Oberholser 1937). Five color morphs are light gray, dark gray, light brown, dark brown, and gray-breasted (upperparts like dark brown morph). Possible other explanations for color morphs include different hormonal levels in different birds (Ripley 1977), hybridization with King Rail (Ripley 1977, Meanley 1985), or previously undescribed variations in plumage progression (WRE). Clarification of color morphs and their significance will depend on detailed study of birds of different age, sex, and genetic background. Feathers from head and neck have tips extended; oval in cross section (Brush 1967). Function of tipping unknown.

Molt and plumage descriptions based on crepitans from Atlantic Coast of U.S., with supplementary information on yumanensis from Arizona. Color terminology follows Ridgway 1912 for crepitans and Smithe 1975–1981 for yumanensis, based on the literature and examination of living specimens. Additional plumage descriptions are presented in Bent 1926, Oberholser 1937, Ridgway and Friedmann 1941, and Ripley 1977 .

Hatchlings

Covered with jet black down with greenish gloss above; blackish-brown below, with slight greenish gloss anteriorly, but abdomen dark blackish clove brown (Oberholser 1937). Individuals have 1–30 white neossoptiles in anterior abdominal region of ventral tract (Wetherbee and Meanley 1965). Presence of these neossoptiles once thought to be a trait that differed between Clapper and King rails, but reflects individual variation (Ripley 1977).

Juvenal Plumage

Prejuvenal molt complete; plumage acquired in first 6–8 wk. Juvenal feathers appear at 4 wk after hatching, first in auricular area, then in ventral and femoral tracts. By age 5 wk, feathers appear in all except capital, caudal, and alar tracts. All tracts have growing feathers by age 6 wk. Plumage begins to be replaced by Basic I plumage shortly after completion of Prejuvenal molt, so molt may appear to be continuous with Prebasic I molt.

Juvenal plumage similar to Basic I for crepitans (see below), but lower back, rump, and uppertail-coverts more uniformly olive brown to sepia, with margins reduced or obscure (Ridgway and Friedmann 1941). Greater and median upperwing-coverts more generally tipped with narrow whitish band and subterminally crossed by narrow white bar. Grayish below, but paler than adult. Abdomen more extensively white; side and flanks mouse gray to deep mouse gray, barred irregularly with grayish white; sides washed with pale cinnamon buff; thighs white anteriorly, deep mouse gray posteriorly. Juvenal plumage in yumanensis similar, but differs greatly from cinnamon buff underparts and brownish upperparts of adult. Some individual juveniles have blackish feathers along sides and flanks; similar to Juvenal plumage of Virginia Rail.

Basic I Plumage

Prebasic I molt partial; does not include rectrices or remiges. Commences when flight-feathers are about half unsheathed (Meanley 1985). Completed between late Aug and Nov on Atlantic Coast of U.S., and between 1 Aug and 31 Oct in Arizona (Oberholser 1937, WRE). Upperparts from forehead to uppertail-coverts, including upperwing-coverts, buffy olive brown to light sepia; feathers of back and rump, and some of upperwing-coverts, conspicuously margined with neutral gray to olive gray, the margins most pronounced on interscapulars, scapulars, and upper back, and the brownish centers of the feathers usually darkest on scapulars (Ridgway and Friedmann 1941). Remaining upperwing-coverts dark buffy brown to olive brown or umber, narrowly edged with slightly paler shade. Rectrices dark olive brown. Superciliary line white, often washed with buffy; lores deep mouse gray with faint brownish tinge; eyelids whitish or pale buffy; cheeks, auriculars, and side of occiput neutral gray to deep neutral gray, washed lightly with brownish in some individuals. Chin and upper throat white; side of neck and lower throat grayish hair brown to dusky grayish buffy brown in some individuals. In other individuals, these areas pale cinnamon buff, slightly clouded with grayish. Breast like lower throat, but paler, less grayish. Abdomen whitish to pale buffy white, sides and flanks barred with dusky drab and white, the white bars about one-third to one-half the width of the dark bars. Crissum like flanks; thighs like abdomen, but washed or barred with dusky drab. Longer undertail-coverts almost entirely white, the others dusky drab barred with white. Underwing-coverts Dresden brown to Prout’s brown, crossed by narrow white bars. Considerable variation in overall plumage color among different subspecies (see Systematics: geographic variation, above).

Alternate I Plumage

Prealternate I molt poorly described. Oberholser (1937) states that Clapper Rails molt only once per year, but year-round trapping in Arizona indicated a second peak in body molt in Oct and a lesser peak in Jan–Feb (WRE). Part of this molt may involve completion of Prebasic molt, but at least some body molt was repeated on retrapped individuals, indicating Prealternate molt. Not known if this molt represented Prealternate I, Definitive Prealternate, or both. Involves head, neck, back, ventrum, leg, tail-coverts, and wing-coverts, and apparently is prolonged through late fall–winter. Similar to Basic I plumage, but Juvenal flight-feathers and possibly tail retained. Body plumage and remiges become much faded and frayed by end of breeding season.

Definitive Basic Plumage

Definitive Prebasic molt complete; occurs after breeding (see Fig. 4). All remiges and all rectrices lost simultaneously; loss of remiges precedes loss of rectrices by a few days (WRE). Duration of flightless period about 1 mo in crepitans, 3.5 wk in yumanensis (Meanley 1985, WRE). Body molt begins about 6 wk before molt of flight-feathers, commencing on head and neck and progressing to all other body regions within 1 mo (Eddleman 1989). Individuals molt wing- and tail-feathers between 10 Jul and 15 Sep. Plumage indistinguishable from Basic I, as far as known.

Definitive Alternate Plumage

Definitive Prealternate molt partial; probably similar to Prealternate I molt (needs more study). Definitive Alternate plumage does not differ from Alternate I.

Color terminology for yumanensis based on Smithe 1975–1981 .

Bill And Gape

crepitans. Bill gray brown along culmen and ventral part of lower mandible; orange yellow or orange red from base to nares on upper mandible and on upper part of lower mandible (Meanley 1985). Color less intense in immature in early fall: light yellowish, straw yellow, or flesh. Gape in adult is orange red, yellowish in juveniles and fall immatures.

yumanensis. Dorsal surface of upper mandible and ventral surface of lower mandible dark grayish brown, sepia, or raw umber in adult; side of bill burnt orange, chrome orange, or orange rufous (WRE). Juvenile bill similar in color to adult bill on top and bottom; side is natal brown or sepia at first, changing by fall to cinnamon drab, smoke gray, or fawn color, then to true cinnamon, light russet vinaceous, or orange rufous. Gape duller than in crepitans and shows little variation with age (WRE).

Iris

crepitans. Reddish orange in adult (Meanley 1985). Eye color dark brown at hatching; turns olive brown or olive drab at about 6 wk; dull brown or orange brown by early fall (Adams and Quay 1958, Meanley 1985).

yumanensis. Amber, raw sienna, Pratt’s rufous, or kingfisher rufous in adult (WRE). Sepia or fuscous in younger chicks, gradually changing to shades of olive (dark brownish olive, olive brown, olive green, or grayish olive), then cinnamon brown, and finally becoming like adult in late summer and early fall.

Legs And Feet

crepitans. Light yellow or pinkish in adults; heel area brighter in some individuals (Meanley 1985). Duller in immature.

yumanensis . Leading edge of tarsus sayal brown, true cinnamon, verona brown, or robin rufous in adult, fading to verona brown or ground cinnamon on trailing edge (WRE). Darker in immatures; light drab or drab gray on leading edges, sepia or dark drab on trailing edge. Toes somewhat darker shade than tarsus.