The grey duck can be found in wetlands throughout New Zealand but mainly in northland, westland, Waikato and Gisborne areas.

Both sexes are alike and similar to the female mallard but darker overall with a striped pale head, grey bill, greenish brown legs, and a green speculum. Because they interbreed extensively with mallards it is often difficult to correctly identify the true grey duck.  Hybrids can have blue speculums, less defined facial stripes, and yellowish brown legs and feet (as in this photograph).  'Pure' grey ducks are found mainly in remote wetlands and rivers - areas that are uncommon to mallards. A decline in population is attributed to the loss of habitat and hybridisation with the mallard.

The diet is mainly aquatic vegetation and grasses close to wetlands borders.  Aquatic invertebrates are eaten during egg laying to strengthen the egg shells.

Breeding is between August and January  in nests built with grasses and lined with down.  The clutch of 3 – 10 eggs is incubated by the female for 26 – 28 days and the ducklings are led to water soon after they hatch. They can have several clutches a season.

Not seen on Tiri in recent years.

Photography by: Max McRae ©

References: Heather, B.D.; Robertson, H.A. 2000 The Field Guide to the Birds of New Zealand. Auckland, Viking.
Moon, G The Reed Field Guide to New Zealand Birds.