White-backed Duck vs Knob-billed Duck

In short

The White-backed Duck and Knob-billed Duck can be distinguished primarily by their bill and head features. The Knob-billed Duck has a distinctive large, black knob on the male's bill, while the White-backed Duck lacks this feature entirely. Both species are part of the same family but differ significantly in appearance and behavior.

Identification tips

• Check the bill: Look for the large black knob on the male Knob-billed Duck's bill.
• Observe plumage: Note the contrasting black and white plumage of the Knob-billed Duck compared to the mottled brown of the White-backed Duck.
• Consider habitat: White-backed Ducks are more likely in dense vegetation, while Knob-billed Ducks are in open water.
• Size and posture: Knob-billed Ducks are larger and more upright in posture.

Size

The Knob-billed Duck is generally larger and more robust than the White-backed Duck.

Plumage

The White-backed Duck has a more cryptic, mottled brown plumage with a white back that is not always visible. In contrast, the Knob-billed Duck has a striking black and white plumage with iridescent green and purple on the wings.

Behaviour

White-backed Ducks are more secretive and often found in dense vegetation, while Knob-billed Ducks are more likely to be seen in open water and are less shy.

Habitat

White-backed Ducks prefer densely vegetated freshwater wetlands, whereas Knob-billed Ducks are found in a variety of wetland habitats, including open lakes and rivers.

Voice

Vocalizations are not a primary distinguishing feature for these species, as both are relatively quiet, but the Knob-billed Duck may produce low grunts.