SPECIES

Kauai Oo Moho braccatus Scientific name definitions

Paul W. Sykes Jr., Angela K. Kepler, Cameron B. Kepler, and J. Michael Scott
Version: 1.0 — Published March 4, 2020
Text last updated January 1, 2000

Identification

Field Identification

Kaua‘i ‘Ö‘ö. Smallest Hawaiian honeyeater; had short tail with no markings, and the least amount of yellow feathering in its plumage among the 4 black-plumaged ‘ö‘ö species, and was last to disappear. Sexes similar in appearance, but female generally smaller. Mass unknown; total length 206–242 mm for males, 179–225 mm for females. Bill about equal to head in length; slender, sharp, and slightly decurved. Nares long (3.8–7.5 mm), narrow, covered from above by small fleshy operculum, and located in groove 6.3–10.8 mm long just anterior to feathering at base of bill. Upper mandible keeled on basal half. Primary extensions (male, BPBM specimen no. 341; female, BPBM specimen no. 14): P10 (27 and 24 mm, respectively) < P9; P9 (11 mm in both specimens) < P8; and P8 (5 mm in both) < P7; P6 and P7 longest. Tail short, graduated, and frequently held cocked upward; rectrices stiff; rectrix extension 2–15 mm; R1 more slender and sharply pointed, and has greatest extension (up to 15 mm). Legs long; feet large. Fine black bristles on chin and throat. Head, wings, and tail black. Crown-feathers stiff and lanceolate; forehead and crown more intensely black than rest of plumage and slightly glossy. Crown sparingly streaked with white. Back slaty brown; rump and uppertail coverts paler brown. Bend of wing and underwing coverts white; axillaries pale grayish buff and tufts undeveloped. Chin, throat, and upper breast black, with transverse subterminal white bars giving scaly appearance. Lower breast and belly slaty brown; undertail coverts rufous brown. Feathered part of leg bright yellow in adults, black in immatures. Plumage more brownish than in the other 3 species of ‘ö‘ö. Appearance unique: small size; short black tail; yellow only at base of legs; pale eye; and fine spot-ting on throat and breast.

O‘ahu ‘Ö‘ö. Slender; similar in size to Bishop's and Hawai‘i ‘ö‘ö (see below). Sexes alike in appearance, but males 20–25% larger than females (see Appendix 3; Wilson and Evans 1890, Lepson 1998). Mass unknown; total length 256–307 mm for males (n = 2), about 235 mm for females (n = 1). Bill approximately equal to head in length; slender, sharp, and slightly decurved. Nares long (7.0–10.2 mm), narrow, covered from above by small fleshy operculum, and located in shallow groove, whose length is about half that of bill, just anterior to feathering at base of bill. Upper mandible somewhat keeled for much of its length.

Plumage sooty brownish black, glossy black on crown; white underwing coverts; bright-yellow sides, flanks, and undertail coverts; and striking pattern of blackish-brown and white wavy bars on undersurface of tail, which appears as white spots dorsally when tail is flared. Yellow feathers of sides formed tufts, as depicted in color lithograph by F. W. Frohawk (Wilson and Evans 1890, Wilson and Buff 1989) from a specimen at the British Museum of Natural History. Feathers of forehead and crown glossy black and scaly. Lepson (Lepson 1998) described 2 specimens (male, ZMB 7851; female, ZMB 7852) having yellow, bare orbital rings, but all others examined were dark in this respect. He suggested that this characteristic is age-related, since it is present in a reduced form in juveniles of other ‘ö‘ö species (Lepson 1998). Specimens lacking bare, yellow orbital rings had short, velvetlike black feathers behind eyes. Auricular tufts inconspicuous, paler and more dusky than rest of face (Lepson 1998). Chin and throat black, with fine bristles on chin. Body black, with brownish tone and pale stri-ations on back, rump, and breast. Wing black, with brown tone; P5–P7 longest. Tail long and graduated; rectrix extension –15 to +24 mm; R1 narrower than r2–R6 and greatly attenuated, distal 40 mm or so filamentous. R1 about equal to or up to 15 mm shorter than r2; r2 generally longest. Tip of R1 is upturned well above rest of tail, and in some males it first curves upward and then curls downward (Gould 1860, Lepson 1998, PWS). R1 is uniform blackish brown; r2–R6 taper to sharp point, with distal 10–20 mm white, contrasting sharply with remaining blackish-brown part of rectrix; white of narrow outer web tends to be slightly longer. Legs long; feet large. Appearance unique: large size; long black-and-white chevron pattern on underside of tail; and bright-yellow flanks and undertail coverts.

Bishop's ‘Ö‘ö. Slender; similar in size to O‘ahu and Hawai‘i ‘ö‘ö. Sexes similar in plumage, but males considerably larger than females (see Appendix 3; Wilson and Evans 1890, Rothschild 1893a). Mass unknown; total length 265–307 mm for males (n = 10), 250–266 mm for females (n = 2). Bill about equal to head in length; slender, sharp, and slightly decurved. Length of tongue (male, AMNH 693922, dried) about 45 mm. Nares long (7.3–10.5 mm), narrow, covered from above by small fleshy operculum, and located in groove 9.5–15.1 mm long, just anterior to feathering at base of bill. Primary extensions (male, BPBM 162): P10 (29.5 mm) < P9; P9 (13.5 mm) < P8; and P8 (3.2 mm) < P7; P6 and P7 longest. Tail long and graduated; extension of R1 (26–51 mm) > r2 in males (n = 4), R1 (18–21 mm) > r2 in females (n = 2). Tip of R1 in male is attenuated, becoming filamentous and sweeping upward with slight curl. r2–R6 broad, coming to sharp point at tips. Rectrices broader in males than in females. Legs long; feet large. Crown-feathers stiff, with scaly pattern. Fine black bristles extend ≤8 mm outward on chin and throat. Feathers of neck and body plumulaceous. Crown, lores, and auricular black, with purple gloss; chin black. Nape, sides of neck, throat, back, rump, sides, flanks, and belly smoky black, with white feather shafts forming fine streaks. Wings sooty, with brown tone; underwing coverts black, or in some individuals mottled white (latter may be related to age or sex). Auricular tufts, black at base, extend rearward ≤ 22 mm; axillary tufts extend ≤ 30 mm. Auricular and axillary tufts and crissum bright yellow. Tail black; in males R5 and R6, and in females R4, R5, and R6, narrowly tipped white on one or both webs. Appearance unique: large size; long black tail; bright-yellow undertail coverts; and bright-yellow ear- and axillary tufts.

Hawai‘i ‘Ö‘ö. Largest ‘ö‘ö, with long, plumelike tail and prominent yellow axillary tufts. Sexes similar in appearance, but female smaller and central pair of rectrices not as elongated or twisted at tip as in male. Mass unknown; total length 286–345 mm for males, 229–278 mm for females. Bill about equal to head in length; slender, sharp, and slightly decurved. Nares long (5.6–8.4 mm), narrow, covered from above by fleshy operculum, and located in shallow groove 6.8–13.3 mm long, just anterior to feathering at base of bill. Upper mandible strongly keeled on basal half; arc of culmen uniform throughout length. Tongue (male, BPBM 3603, dried) about 33.96 mm long and 3.3 mm at widest point; left fork 12.62 mm long, right fork 12.68. Stomach small for size of bird (Henshaw 1902a)—an adaptation to high-energy, low-volume diet of mainly nectar. Primary extensions (male, BPBM 5): P10 (32 mm) > P9; P9 (19 mm) < P8; and P8 (6 mm) < P7; P6 and P7 longest. Tail long and strongly graduated, frequently raised above back in threat and courtship displays (Perkins 1903); jerks tail up and down often when perched (Wilson 1890a). R1 extension 52–59 mm in males (n = 10), 23–36 mm in females (n = 8). r2–R6 extensions 10–27 mm in males (n = 10), 8–26 mm in females (n = 8). Tip of R1 attenuated, and in males, distal one-third to one-half of R1 curled. Apices of r2–R6 are obtuse, tending toward mucronate. Legs long; feet large. Fine black bristles on chin and throat project outward up to 6 mm. Feathers of crown stiff. Forehead, crown, and nape scaly; scaliness present but less pronounced on back, breast, and belly. Scaly appearance produced by base of feather being dull along base of shaft with glossy margin. Plumage deep glossy black, with bluish sheen; duller on lower abdomen and uppertail coverts; in some specimens, faint brownish-yellow wash on auriculars. Axillary tufts and undertail coverts bright yellow. Axillary tufts consist of 16–20 feathers (Rothschild 1893a); project outward when erect 12–40 mm and sweep rearward; width front to rear is up to 45 mm; longest in adult males. Upper surface of wing glossy black; front edge of wing at bend white for about 25 mm; greater underwing coverts mottled white. Tail all black, without blue sheen in R1–R4. R5 and R6 similar; basal half of inner web black or brown, remainder white (see description of Definitive Basic plumage under Appearance for detail). R5 has conspicuous broad black or blackish-brown shaft-streak, becoming lance- or teardrop-shaped near tip; in R6, streak may be reduced in size or absent. Appearance unique: large size; long black tail, with white and yellow outer margin at base; and bright-yellow undertail coverts and axillary tufts.

Kioea. Largest, little-known, and only Hawaiian honeyeater with streaked brown plumage lacking yellow patches or feather-tufts. Slender and cuckoolike in appearance. Sexes apparently alike, but may differ in size, as in typical meliphagids. Mass unknown; total length 320–345 mm. Bill longer than head; long, slender, sharp, and decurved throughout length. Nares long and narrow, covered from above by small fleshy operculum, and located in shallow groove 12 mm long (BPBM 17; sex unknown), just anterior to feathering at base of bill. Upper mandible keeled near base. Primary extensions (BPBM 17): P10 (29.6 mm) < P9, P9 (19.2 mm) < P8, and P8 (6.7 mm) < P7; P5, P6, and P7 longest and about equal length. Tail long and strongly graduated; rectrix extension 11–17 mm; all rectrices obliquely pointed at tips, but central pair tend to be slightly more pointed than the other 5. Legs long and sturdy; feet large. Contour feathers of head, neck, and underparts plumulaceous. Black bristles curve outward from tips of contour feathers ≤10 mm on chin and throat and at base of bill, and ≤5 mm on forehead and crown. Head, neck, upper back, chin, throat, breast, and abdomen streaked brown and grayish white, more boldly on breast and abdomen; some yellowish tinge to crown and hindneck; black mask through eye; wings and tail brown, tinged with yellow-green; lower belly, flanks, crissum, and rump light ochreous. Plumage coloration and pattern unique among Hawaiian birds. Appearance unique: large size; brownish instead of black plumage; no yellow feathering; boldly streaked below; and dark mask.

Recommended Citation

Sykes Jr., P. W., A. K. Kepler, C. B. Kepler, and J. M. Scott (2020). Kauai Oo (Moho braccatus), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.kauoo.01