| Wrybill | |
|---|---|
 | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Charadriiformes |
| Family: | Charadriidae |
| Genus: | Anarhynchus |
| Species: | A. frontalis |
The Wrybill (Anarhynchus frontalis), locally known as Ngutuparore in Maori, is a species of wader endemic to New Zealand. It is most well known for being the only bird with a sideways bill.
Description[]
Wrybills are small, easily distinguishable 20-21 cm long pale plovers, weighing from 43-71 g in mass, with a long black bill curved sideways. They have white underparts with a black upper breast band from mid-winter to the end of the breeding season. The upper parts and sides of the face are pale grey and the forehead is white. Male Wrybills in winter are distinguishable by a black line above the forehead; however, this is very variable and can be difficult to see in some individuals.
Behavior[]
Wrybills usually allow a close approach. When incubating, they rely on camouflage to avoid detection, and flush from the nest very late. Distraction displays are used to defend nests; Banded Dotterels are aggressively chased if close to eggs or chicks. Chicks freeze to escape detection (especially when small), and swim well from a few days old. Away from the breeding grounds, Wrybills are highly gregarious and form dense flocks, normally also very approachable.
Northward migration typically begins in late December, and peaks in January. Southward migration is mainly in August and early September (adults), with some first-year birds (which will not breed) following in October-November.
Feeding[]
Wrybills feed on a varied range of aquatic vertebrates on the breeding grounds, predominantly mayfly and caddisfly larvae. On wintering grounds, a range of small marine and littoral invertebrates are taken (including annelid and polychaete worms, small molluscs, and insects), as well as, occasionally, small fish.
Breeding and Nesting[]
Wrybills breed in monogamous dispersed pairs. Territories may overlap with those of other species (e.g. Banded Dotterel, Black-fronted Tern, Pied Stilt), but are vigorously defended against other Wrybills. The nest is a shallow scrape in the gravel, lined with many small stones. Normally 2 eggs are laid; first clutches are laid in September or October. Replacement clutches laid after loss may occur through to January. Some pairs will double-brood if they are successful early. Incubation is shared and is protracted; accurate data are few, but values from 30-36 days recorded. Chicks fledge after 35-40 days and are guarded by one or both parents during their first 3 weeks at least, often becoming increasingly independent before fledging.
Distribution and Habitat[]
Wrybills breed only in South Island, east of the main divide. From January to July, Wrybills are present in harbours of the northern North Island, mainly Manukau and Firth of Thames, smaller flocks elsewhere. During migration, small flocks are often seen briefly at South Island east coast lakes and estuaries, and flocks may settle at rivermouths in the southwestern North Island. They breed exclusively on braided riverbeds and winter in harbours and estuaries, feeding on inter-tidal mudflats.