The Hawaiian duck or koloa is a species of bird in the family Anatidae that is endemic to the large islands of Hawaiʻi. Taxonomically, the koloa is closely allied with the mallard. It differs in that it is monomorphic and non-migratory. As with many duck species in the genus Anas, Hawaiian duck and mallards can interbreed and produce viable offspring, and the koloa has previously been considered an island subspecies of the mallard. However, all major authorities now consider this form to be a distinct species within the mallard complex. Recent analyses indicate that this is a distinct species that arose through ancient hybridization between mallard and the Laysan duck. The native Hawaiian name for this duck is koloa maoli, or simply koloa. This species is listed as vulnerable by the IUCN Red List of Threatened Species, and its population trend is increasing.
Region
Hawaiian Islands
Typical Environment
Occurs in freshwater wetlands, irrigation ditches, taro patches (loʻi kalo), lowland marshes, and slow-moving streams. It also uses forested riparian corridors and upland ponds when available, especially where wetlands are scarce. Birds are most numerous on Kauaʻi, with reintroduced and mixed populations on Oʻahu, Maui, and Hawaiʻi Island. They avoid highly urbanized shorelines but will use agricultural wetlands when disturbance is low.
Altitude Range
Sea level to 2000 m
Climate Zone
Tropical
Ease of Keeping
Beginner friendly: 1/5
Also called the koloa maoli, the Hawaiian duck is a monomorphic, non-migratory dabbling duck endemic to the main Hawaiian Islands. It is closely related to the mallard and interbreeds with feral mallards, making hybridization the primary conservation threat. Predator control, wetland restoration, and removal of feral mallards are key recovery actions. Genetic studies suggest it arose from ancient hybridization between mallard and Laysan duck lineages.
Hawaiian duck x mallard hybrid pair, Maui
Temperament
wary and somewhat secretive
Flight Pattern
strong flier with rapid wingbeats
Social Behavior
Usually found singly, in pairs, or small family groups; forms loose aggregations where habitat is concentrated. Pairs form seasonally and nesting is on the ground near water in dense vegetation. Clutches are moderate-sized, and females lead broods to shallow, vegetated wetlands shortly after hatching.
Migratory Pattern
Resident
Song Description
Females give a typical mallard-like series of quacks, often louder during contact or alarm. Males produce softer, rasping or wheezy notes and low grunts during courtship.
Plumage
Overall mottled brown body with darker crown and finely streaked head and neck; sexes similar. The speculum is iridescent greenish to blue with little or no white bordering. Tail and rump are darker, with subtle pale edging on body feathers giving a scaly look.
Diet
Feeds by dabbling and upending, taking seeds of sedges and grasses, aquatic plants, algae, and agricultural grains where available. It also consumes aquatic invertebrates such as insects, snails, and crustaceans, especially during breeding and for duckling growth. Opportunistic foraging includes gleaning along muddy margins and shallow flooded fields.
Preferred Environment
Shallow, vegetated freshwater habitats with abundant emergent plants and invertebrates. Frequently uses taro patches, ponds, and slow streams with overhanging cover to reduce predation risk.
