Wrybill  (Anarhynchus frontalis)

Classified as Vulnerable (VU) on the IUCN Red List 2006 (1).

The wrybill is a distinctive wading bird, which possesses a uniquely bent bill. The tip of the black bill is curved to the right, this adaptation allows these birds to forage under stones for insect larvae (3). The plumage is ash-grey above with white underparts. During the breeding season, individuals have a black band across the upper chest and males also have a band on the forehead (2).

Endemic to New Zealand, wrybills migrate annually from breeding grounds in Canterbury and Otago (on South Island), to spend the winter in northern areas of North Island (2).

Breeding occurs on rivers where there are large amounts of bare shingle. The wintering sites to the north tend to consist of mudflats at the mouths of large rivers (4).

The laying season runs between September and October; a clutch of two eggs is laid into a slight depression amongst the gravel. Both parents take it in turn to incubate the eggs that are well camouflaged against the shingle, resembling the stones around them (4). The parents also rely on camouflage to remain undetected with their ash-grey plumage barely visible amongst the stones (4). The chicks are able to leave their nest within a day of hatching and follow their parents on foraging trips (4).

Birds begin to leave the breeding grounds by late December; this species is one of the first of the season to begin its migration (4). Using its specially adapted beak, the wrybill is able to forage under stones for invertebrates such as mayfly larvae (3).

Large flocks of wrybills were recorded in the early 19th century but the species has since undergone a long-term decline, principally as a result of habitat loss at breeding sites (2). The shingle beds that comprise the nesting habitat of this species have decreased in size due to the encroachment of weeds, and altered river flooding regimes caused by hydroelectric schemes (2). It is also likely that predation by introduced stoats (Mustela erminea) and cats has played a large part in the decline of this ground-nesting bird (2).

The wrybill became fully protected in New Zealand in 1940 (2). Research is currently being undertaken into the impact of predation on wrybill population numbers (2). Long-term monitoring is vital in determining the overall trends in this threatened species (2).

View information on this species at the UNEP World Conservation Monitoring Centre.

BirdLife International’s World Bird Database
http://www.birdlife.org/datazone/search/species_search.html