Grey teal

Did You Know?

• In 1957, large numbers fled Australia, moving to New Zealand to escape a drought.
• Its Māori name in New Zealand is tētē.

Description

The grey teal is a mottled brown duck with white and green flashes on its wings. Males and females share the same colouration, unlike the related chestnut teal where the sexes are strikingly different. The grey teal closely resembles the female chestnut teal but can be distinguished by its lighter neck and paler face. Juveniles are paler than adults, especially on the head, and have a dull brown eye until they mature.

The bill is blue-grey with dark edges, and the feet are a similar grey. The head is plain or slightly streaked, with a dark crown and cream-coloured chin, throat and cheeks. The iris is crimson, more prominent in adult males. Eggs are creamy white and not distinctly speckled, averaging 49.3 mm in length and 35.6 mm in width.

The grey teal nests near freshwater lakes and marshes, usually on the ground but also in tree holes or rabbit burrows. It is a vocal duck, especially at night: the male gives a soft preep and the female a loud quack. It is gregarious and nomadic in Australia, rapidly colonising suitable habitat after rain. Adults undergo a flightless moult not fixed in the year; before breeding they have a body moult excluding wings, and after breeding a complete body moult including wings.

In Australia the moult correlates with climate conditions: during a prolonged wet season wing moult is postponed to extend breeding. Body moult (including wings) generally occurs between January and March. Juveniles moult the entire body except the wings in their first autumn or early winter.

Range

The grey teal breeds in Australia, New Zealand, New Guinea and Indonesia, and is vagrant in the Solomons and New Caledonia. It self-introduced to New Zealand from Australia, where it is much more abundant. Rare in New Zealand until the 1950s, it is now a very common waterbird found throughout the country, with larger populations in Hawke's Bay, Waikato, South Auckland and Otago, and also in the Canterbury region around Lake Ellesmere. It has wandered to the Chatham Islands and Snares Islands. The New Zealand population is smaller than the Australian one.

Ecology

Male grey teal establish pair-bonds through displays such as headshakes and head rolls; these occur in adolescent birds before breeding, while mature birds in established pairs use courtship rituals. Pair-bonds are long-term and monogamous, with couples staying together all year, though after late summer moult they often join large flocks until July. After breeding they frequently gather at estuaries to feed on exposed mudflats. Breeding typically starts at one year old.

In Australia breeding is linked to rainfall and food abundance, with no fixed season, and the species adapts to breed in shallow temporary water. In New Zealand, where the climate is more humid, breeding is more seasonal but still related to water level; laying occurs between June and September, with replacement clutches through to January. Nesting is usually solitary, though sites may be close together. Nests are in tree hollows or hidden among ground vegetation, using grass and down; the female creates a bowl filled with litter and surrounded by down.

Clutch size is 1–7 eggs. In South Australia nesting occurs between June and February, slightly later in North Australia due to temperature differences; in New Zealand nesting is between September and November.

Relationship with humans

The grey teal is fully protected in New Zealand. The population there rose from an estimated 20,000 birds in 1976 to 50,000 in 2005 and about 120,000 in 2014, with over 1 million worldwide. Despite its common status, the government considered adding it to the game bird list during a 2010 review of the Wildlife Act but did not, keeping its conservation status. This caused tension between the Department of Conservation and hunters, who felt misled for decades; penalties apply for killing the bird, yet hunters often shoot grey teal accidentally as it flies among game duck flocks.

At least 6% of the New Zealand population is shot during the hunting season. In Australia the grey teal is one of the most common birds shot; in Victoria the hunting season lasts three months (compared to five weeks in New Zealand) with a daily bag limit of ten. A Victorian survey found about 26% of shot grey teal are wounded or mutilated: 12% wounded and surviving, and between 14% and 33% mutilated.