HAWAIIAN DUCK 
ANAS WYVILLIANA Sclateb 
(Plate 21) 
Synonymy 
Anas boschas? Hartlaub ()iec Linne), Arch. f. Nalurgesch., vol. 1, p. 137, 1852. 
Anas superciliosa Dole (nee Gmelin), Proc. Boston Soc. Nat. Hist., vol. 12, p. 305, 
1869. 
Anas superciliosa a. sandwichensis Bonaparte, Compt. Rend. Acad. Sci. Paris, vol. 
43, p. 649, 1856 {nomen nudum). 
Anas wyvilliana P. L. Sclater, Proc. Zool. Soc. London, 1878, p. 350. 
yl«as a6cr(i Ridgv ay, Proc. LhS. Nat. Mus., vol. 1, p. 250, 1878. 
Vernacular Names 
English: Hawaiian Duck, Sandwich Islands Duck. 
Hawaiian: Koloa Maoli. 
DESCRIPTION 
Adult Male: “Top of the head blackish, the feathers tipped with pale brown. A dark metallic green 
stripe from the eyes to the nape. Feathers of the neck blackish, mixed with light brown, those of the 
upper back and interscapular region blackish brown with crescent -shaped and undulated rufous- 
browm bands. Lower back, rump, and upper tail-coverts brownish black, with but a few brown 
feather-edges and spots. Inner tertials and greater scapulars browm, greyish in the middle and nar- 
rowly edged with pale browm. Primaries dark greyish brown. The secondaries form a large and fine 
speculum, bordered behind with a subterminal black line, followed by a white terminal line, and in 
front by a black line, with a less defined grey band before it. Above the speculum is bordered with a 
broad velvety-black stripe, formed by the black outer webs of some of the tertials. Rectrices deep 
bro'wn and blackish, with whitish-brown edges and irregular arrow-shaped markings. The two 
central rectrices are black, soft, and curled up as in Anas boschas; in one old male in abraded 
plumage the next [lateral feather on one side] shows an inclination to curl up (the other corre- 
sponding one being absent), and in two other males there is a distinct beginning to curl up. Sides of head 
and neck and throat mottled with blackish brown and pale buffy brown. Throat blackish in the 
oldest male. Breast rufous brown, with U-shaped blackish markings, or more or less rounded spots, 
these standing before the tips of the feathers and being followed by another blackish mark; the upper 
breast and sides more rufous. Abdomen brownish buff, distinctly shaded with greyish in the 
oldest specimens, and varied with greyish-brown spots, in the most matured specimen distinctly, 
though faintly, cross-barred with ashy brown. Sides of body pale rufous browm, with longitudinal 
or V-shaped deep brown markings, but in the oldest male some white feathers finely undulated with 
blackish brown appear on the flanks. Under tail-coverts blackish and brownish, varying much and 
strongly tinged with rufous in older specimens. Under wing-coverts and axillaries white.” 
Wing 236-249 mm.; tail 89; culmen 48; tarsus 40.5 (Rothschild, 1900). 
Adult Female: “Blackish brown above with a slight gloss on the head, all the feathers broadly 
