Banded Dotterel

The double-banded plover (''Charadrius bicinctus''), known as the banded dotterel or pohowera in New Zealand, is a species of bird in the plover family. Two subspecies are recognised: the nominate ''Charadrius bicinctus bicinctus'', which breeds throughout New Zealand, including the Chatham Islands, and ''Charadrius bicinctus exilis'', which breeds in New Zealand's subantarctic Auckland Islands.

Taxonomy

A 2015 study found its closest relatives to be two other plovers found in New Zealand, the New Zealand dotterel (''Charadrius obscurus'', also called the New Zealand plover) and the wrybill (''Anarhynchus frontalis'', which the study found to be in the ''Charadrius'' clade).

Description

The double-banded plover is distinguished by a dark, grey-brown back with a distinctive white chest and a thin band of black situated just below the neck running across the chest along with a larger brown band underneath. During breeding season, these bands are more dominantly shown on the males compared to females. Younger birds have no bands, and are often speckled brown on top, with less white parts. These shorebirds have relatively long legs to allow them to easily wade around shallow waters and move efficiently around sandy beaches. Their long pointed wings aid in traveling long distances as they allow the bird to be very agile. The double-banded plover's head is prominent with large, dark-brown eyes and a sturdy black bill. Due to similar colors within the plovers ideal habitat, spotting these birds can be difficult to achieve, however the "chirp-chirp" call is easily heard and their habit of running quickly then pausing to feed on food can catch the eye of observers.

Distribution and habitat

Distribution of the banded dotterel varies seasonally. They are at their breeding grounds, which are entirely in New Zealand, from roughly August to November. Many move to coastal locations in New Zealand in the immediate post-breeding season (roughly December to March). A large proportion of the population migrates to Australia in autumn and winter (roughly April to July).

Banded dotterels breed throughout much of the North and South islands and their offshore islands, plus Stewart Island, the Chatham Islands and the Auckland Islands. The largest number nest on the braided riverbeds of Marlborough, Canterbury, Otago and Southland in the South Island. Many others breed on shingle riverbeds in Hawke's Bay, the Manawatu and the Wairarapa in the North Island. Some nest on sandy coasts, especially near the mouths of streams or rivers in the North and South islands. Small numbers breed in higher altitude areas such as Tongariro National Park and subalpine areas of Central Otago.

In the summer months of December to March the birds disperse somewhat from their breeding grounds, with many that nest in inland locations moving to estuaries and other coastal wetlands. In autumn and winter many move further, with most that nest in the riverbeds and outwash fans of the South Island high country migrating 1,600 kilometres or more to south-eastern Australia, including Tasmania, remaining there until mid-winter. This more or less west–east flight is uncommon for migratory birds and unique among migratory wading birds, which usually fly on a north–south axis. Birds that breed in the South Island lowlands, the northern South Island and the southern two-thirds of the North Island mostly stay on the New Zealand coast, throughout the country, with some moving to harbours and estuaries in the northern North Island. Dotterels that nest near coastal wintering grounds may move only a few kilometres. Populations in the Chatham and Auckland Islands generally move only locally throughout the year, although a few from Auckland Island venture to Campbell Island. Vagrant birds reach New Caledonia, Vanuatu and Fiji.

Northern populations of banded dotterel commonly inhabit sandy beaches and sandpits, as well as a few pairs accustoming to shell banks in harbours, with a few found on gravel beaches, with nesting sites generally clustered around stream-mouths. In the breeding period, males construct numerous nests on open patches of slightly elevated sand or on shells and occasionally in cushion plants which are all mostly padded with various materials retrieved from close by. Birds in the southern parts of New Zealand, such as Stewart Island, prefer to breed on unprotected subalpine and stony areas, but become coastal during off-breeding months where they feed around the beach areas.

Behaviour

Breeding

Banded dotterels start returning to North Island breeding areas in June–July and to inland Canterbury areas in August–September. They form seasonal monogamous pairs where once a partner is found, they remain with that one bird for the rest of the breeding season to help raise the young. During this time, the male grows colored bands on his chest prior to the beginning of the breeding season and later females are attracted by the loud calls of the male where they are then presented with several nests which they can choose between while the male puts on a defensive display, protecting his territory, where it flies towards any possible intruder in a fast butterfly-like circular motion flight. This species usually constructs nests upon slightly elevated, open patches on the sand, shells or sometimes hollows in cushion plants or between rocks which are broadly padded with various materials such as tussock tillers, smaller stones and shells, grass, lichen

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