The wrybill or (in
Māori
Māori or Maori can refer to:
Relating to the Māori people
* Māori people of New Zealand, or members of that group
* Māori language, the language of the Māori people of New Zealand
* Māori culture
* Cook Islanders, the Māori people of the C ...
) ngutuparore (''Anarhynchus frontalis'') is a species of
plover
Plovers ( , ) are a widely distributed group of wading birds belonging to the subfamily Charadriinae.
Description
There are about 66 species in the subfamily, most of them called "plover" or "dotterel". The closely related lapwing subf ...
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
. It is the only species of bird in the world with a beak that is bent sideways in one direction, always to the right (in the
crossbill
The crossbill is a genus, ''Loxia'', of birds in the finch family (Fringillidae), with six species. These birds are characterised by the mandibles with crossed tips, which gives the group its English name. Adult males tend to be red or orange in ...
s, e.g. ''
Loxia pytyopsittacus
The parrot crossbill (''Loxia pytyopsittacus'') is a small passerine bird in the finch family Fringillidae. It breeds in pine forests in northern and northeastern Europe.
Taxonomy
The parrot crossbill was species description, formerly described i ...
'', the tips of the upper and lower mandibles cross because they are bent sideways in opposite directions, sometimes left over right and sometimes right over left). A 2015 study found it to be within the ''
Charadrius
'' Charadrius '' is a genus of plovers, a group of wading birds. The genus name ''Charadrius'' is a Late Latin word for a yellowish bird mentioned in the fourth-century Vulgate.
They are found throughout the world.
Many ''Charadrius'' species a ...
'' clade, with other New Zealand plovers its closest relatives; the nearest being the
New Zealand dotterel
The New Zealand dotterel (''Charadrius obscurus'') is a species of shorebird found only in certain areas of New Zealand. It is also called the New Zealand plover or red-breasted dotterel, and its Māori names include , , and .
The southern ...
or New Zealand plover (''Charadrius obscurus''), and then the
double-banded plover
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 ...
or banded dotterel (''Charadrius bicinctus'').
It lays its eggs among the rocks along rivers and distracts intruders by pretending to be in distress and moving away from its
clutch
A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...
.
It is rated as
vulnerable on the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
(IUCN)'s
Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...
of Threatened Species.
Taxonomy
French naturalists
Jean René Constant Quoy and
Joseph Paul Gaimard described the wrybill in 1830.
Description
![Wrybill](https://upload.wikimedia.org/wikipedia/commons/b/ba/Wrybill.jpg)
The wrybill is a small, plump plover, measuring in length and weighing between . The
plumage
Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...
is slightly
sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
. The male has a white forehead and pale grey crown, nape, back, wings and tail and a white throat, breast, belly and rump, with a thin black band across the breast. This band is thinner in the female, and much less distinct in both sexes in the non-breeding season. The other difference between the sexes is a small black bar between the white forehead and the grey crown, which is present in the males but not the females. As with the breast band it is reduced in the non-breeding season. The most distinctive feature of the bird is the long black
bill
Bill(s) may refer to:
Common meanings
* Banknote, paper cash (especially in the United States)
* Bill (law), a proposed law put before a legislature
* Invoice, commercial document issued by a seller to a buyer
* Bill, a bird or animal's beak
Plac ...
, which is always curved to the right. The wrybill is the only species of bird with an asymmetrically turned bill.
The eggs are very pale grey and covered with very small brown spots which blend in very well to the surrounding shingle
As well as the eggs being very well camouflaged, the adult birds and chicks are very difficult to see when they are standing still.
[Heather, B & Robertson, H. (2005). The field guide to the birds of New Zealand. Auckland: Penguin Books (NZ) Ltd]
Chicks are very pale grey on upper half of body with black speckles and white on lower half of body grey.
[Complete book of New Zealand birds (1985). Sydney, New South Wales: Reader’s Digest Services Pty Limited]
The wrybill's voice has been described as a short ''weet'' when in flight and used to signal alarm, and a harsher call is used to signal greater alarm. A chirring sound is used to challenge an aggressor. Fledglings and juveniles have a high-pitched short peep.
Distribution and habitat
The wrybill is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to New Zealand. It breeds on large braided rivers in Canterbury and Otago,
South Island
The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...
, preferring large dynamic rivers that will not become overgrown with weeds. The main breeding rivers include the Waimakariri, Rakaia, Rangitata, Waitaki and Ashley.
It used to occur more frequently on smaller rivers, but has undergone a range contraction, and now only occupies around 60% of its estimated original range.
After breeding, around late December till early February, they leave their breeding sites and migrate to shallow estuaries and sheltered coastal areas in the North Island. These areas include Firth of Thames, Manukau Harbour, Kaipara Harbour and Tauranga Harbour.
Behaviour
Wrybills like to roost in large flocks during winter which differs greatly from breeding time when they become very territorial towards other birds. They usually roost on one leg and hop away when approached too close.
Wrybills are known to perform large aerial displays with their flocks. This usually happens shortly before the migration south.
Breeding
![Wrybill eggs 2](https://upload.wikimedia.org/wikipedia/commons/6/6d/Wrybill_eggs_2.jpg)
Wrybills form monogamous bonds with their mates and will return to the same territory each year to breed again. If their mate does not return, the bird will move territories. Nesting
territories
A territory is an area of land, sea, or space, particularly belonging or connected to a country, person, or animal.
In international politics, a territory is usually either the total area from which a state may extract power resources or a ...
are strongly defended. These can be anywhere between 1 and 11 hectares in size, with an average size of 5 hectares. They show strong
philopatry
Philopatry is the tendency of an organism to stay in or habitually return to a particular area. The causes of philopatry are numerous, but natal philopatry, where animals return to their birthplace to breed, may be the most common. The term derive ...
to their territories, and young birds show strong philopatric tendencies towards breeding close to where they were hatched.
Many breeding pairs will lay two clutches in a breeding season, especially if the first clutch was destroyed by flooding or predators.
Nesting sites are shallow scrapes in areas of large stones or sand. The
clutch
A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...
size is two eggs, which are incubated by both parents (but more so by the female) for 30 to 36 days. The chicks have downy feathers on hatching, grey to off-white above and white underneath. Both parents attend to the chicks, which fledge after around 35 days and are immediately independent after this. Young birds start breeding when they are two years old.
Ecology
Moulting of wrybills happens between December and May. The moulting process advances quickly at the start of the process, when the first feathers are dropped, and slows as the longer outer feathers start to grow.
Migration starts in November with the earliest fledged birds. Adults follow in January–February when breeding is finished with the rest of the fledglings.
Migration back to breeding sites in the South Island happens in August.
The current population is around 5000 individuals.
Diet and foraging
Wrybills are usually found foraging around shallow channels and around the edges of pools on insect larvae, aquatic invertebrates and sometimes small fish. They have evolved in a very distinct way to thrive on braided river beds: their beak is slightly tilted towards the right at an angle of about 12–26 degrees which is speculated to help them get insect larvae and small invertebrates that take refuge under the crevices of rocks; however this has never been conclusively proven.
Predators and threats
Threats are higher during the breeding season when the birds are at their most vulnerable. Threats include predation, flooding during nesting time, habitat degradation and disturbance from vehicles along the river beds. Introduced mammalian predators such as ferrets, stoats, weasels and hedgehogs pose a significant threat to the survival of the remaining population. Wrybills have adapted to bird predators such as raptors, gulls and owls, since mammalian predators have only been a threat since the arrival of people. Their chicks and eggs blend in very well with the surrounding shingle, camouflaging them from the predators flying overhead. Since rabbits are the main diet of introduced mammalian predators, when rabbit numbers are low these predators search further for their food and prey upon the ground nesting birds on the braided rivers. Flooding can destroy nests and disturb whole nesting areas, and can affect the number of chicks to reach fledging. As wrybills prefer an open clear area of shingle on the river bed to nest, introduced plant species such as
gorse
''Ulex'' (commonly known as gorse, furze, or whin) is a genus of flowering plants in the family Fabaceae. The genus comprises about 20 species of thorny evergreen shrubs in the subfamily Faboideae of the pea family Fabaceae. The species are n ...
(''Ulex europaeus''),
willow
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
(''Salix'' spp.),
broom
A broom (also known in some forms as a broomstick) is a cleaning tool consisting of usually stiff fibers (often made of materials such as plastic, hair, or corn husks) attached to, and roughly parallel to, a cylindrical handle, the broomstick. I ...
(''Cytisus scoparius'') and
lupin (''Lupinus'' spp.), all threaten the wrybill's habitat as they spread over the landscape easily and quickly.
Conservation status
The wrybill is rated as
vulnerable on the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
(IUCN)'s
Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...
of Threatened Species,
The population declined during the 1800s as they were collected as museum specimens because of their strange bent bill. In 1940 they were protected and the population has increased from around 2000 birds to 5000 birds today.
References
External links
BirdLife Species Factsheet.Wrybill, New Zealand Birds Online
{{Taxonbar, from=Q901136
Endemic birds of New Zealand
Charadriinae
Birds described in 1830
Taxa named by Jean René Constant Quoy
Taxa named by Joseph Paul Gaimard