Hitherto normally included within A. platyrhynchos. Probable unstable hybrids of A. superciliosa and present species, A. platyrhynchos or A. wyvilliana, found on some Micronesian islands, have been considered a different species, Mariana Duck (A. oustaleti). Most closely resembles A. wyvilliana, but differs in smaller size (mean male weight 456 g vs 638 g#R) (score at least 2); structurally different femur and middle toe (allow 1); dark chocolate-coloured head (3); large white eyering (2); darker overall plumage (1); and distinctive feeding ecology (1). Monotypic.
Laysan I, NW Hawaii Is.
Food and feeding
Status and conservation
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