254:(SIPO are around 550 grams). Occasionally completely black, but if they are pied (black and white) they can be easily confused with SIPO. The variable species has less definition between the black and the white area, as well as a mottled band on the leading edges of the underwing. Variables also have a smaller white rump patch which is only a band across the base of the tail rather than a wide wedge shape reaching up to the middle of the back as in the SIPO. When mottled they are sometimes called "smudgies". While both sexes have the same plumage colorations and appear visually similar, there is some body dimorphism and female oystercatchers tend to be slightly larger in size.
325:
days. Nests consist of scrapes in the sand, usually surrounded by some vegetation for concealment. Both parents take turns guarding the nest from predators until the chicks hatch and fledge between the following
February–March. Chicks are well camouflaged by their colour and can fly in about 6 weeks. The fledging period lasts for approximately 20–50 days, but can be longer. During this time, the adults may also begin moulting, with data suggesting moult timing anywhere between December–July. At 6 weeks, the chicks are able to fly, and will begin foraging by themselves within their parent's territory.
396:, a cestode, is found exclusively on Variable Oystercatchers. Most recently, a tapeworm was discovered in an individual during research that required handling of the birds in Tasman Bay, and was the first instance of a wild bird species ever contracting a tapeworm. These parasites do not harm the host, and are expected to simply consume a small supply of resources that the bird intakes. Similarly, disease is not a large contributing factor to mortality. Avian pox has been documented, but does not appear to be problematic for the species and rarely causes death.
31:
321:
other males. This display includes several 'bowing' or 'ducking' movements, where the bird tilts and dips its head while making piping calls. These movements are also used to distinguish territory space outside of the mating season, when the adult birds prefer living in solitary environments. After a female has decided to breed with a male, the pair remains monogamous during the rest of the mating season and potentially for several consecutive years thereafter. During breeding, the pair will defend their territory, sometimes aggressively.
80:
243:
392:, dogs, cats and possibly rats (Marchant, 1993). The variable oystercatcher has issues with disturbance from human activity which damages nests. Habitat loss such as decreasing coastal dunes that provide essential breeding locations for the species are likely to have a large impact on all populations. Fishing nets and oil spills also pose threatening for the species. Additionally, parasites from genera such as Cestoda and Digenea have both been found in individuals. Specifically,
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probing with the bill. Their diet consists of a range of molluscs, crustaceans, worms, small invertebrates and sometimes small fish. The molluscs are mainly bivalves and are opened by the birds by using the bill to stab and twist them open. Some birds have been observed to hammer them open. After heavy rain, they sometimes go inland in search of earthworms.
234:"Variable" refers to the frontal plumage, which ranges from pied through mottled to all black. They are polymorphic meaning they have different genetic variants. These color differences are attributed to the latitude of the habitat, where the northernmost oystercatchers have significantly more white on their bodies than those of southern origin. All
305:
266:
the North, South and
Stewart Islands coastlines and some offshore islands with the exception of outlying islands off the west coast. While they occur in lower densities on the western coastlines they are concentrated in these areas; Northland, Coromandel Peninsula, Bay of Plenty, Greater Wellington, Nelson/Marlborough and Fiordland.
345:
is currently estimated to have 4,000–5,000 individuals total. Although this number appears low, the species is considered of least concern ecologically and noted to be in acceptable health. While no conservation efforts are in effect, other pieces of legislation that protect threatened and endangered
273:
is generally never found more than 30 km from the coast. Breeding and nesting occurs on sandy coasts, usually far from muddy harbours. Individuals have been known to congregate in short grassed paddocks and sometimes forage in pastures after rain however will generally remain around the coastal
238:
variable oystercatchers are black. They have pink legs, an orange eye ring and orange-red beaks. Similar to a needle in shape, the bill is thin and long, and darkens to a deep red color during the breeding season. Males are around 678 grams and females slightly larger at around 724 grams. Length of
265:
is endemic to New
Zealand. The species has likely remained endemic due to its sedentary lifestyle and lack of migration, keeping all populations within the same island habitat. They are often seen in pairs on the coast all around New Zealand. Their distribution around New Zealand is around most of
320:
As a sedentary species, the oystercatchers do not travel to a specific location to mate. Instead, they breed on the coastal sand dunes where they live nearly year-round. After finding a potential mate, the male oystercatcher will give a territorial display to both impress the female and scare off
324:
Stone-coloured eggs, usually in clutches of 2–3, are laid from
September to December, and the nest is incubated by both parents until the chicks hatch. They usually lay 2-3 eggs but they can lay up to 5. The eggs are typically stone coloured with small brown patches all over. Eggs hatch in 25–32
328:
By the beginning of their first fall season, usually early August, the young leave their parent's care and join other juveniles to form a loose flock. These juveniles will remain together until they are about 2 years old, where they will then disperse to find their own territories and breeding
295:
Feeding behaviour is diurnal and nocturnal with no feeding occurring two hours either side of high tide. The birds will then start feeding as the tide ebbs. Food is located mainly by visual location but when it is dark or the food is obscured by the substrate, they will locate food via random
333:(SIPO) which also have vivid orange beaks. Maturity is thought to be around 3 years of age, and most individuals begin breeding within 3–6 years of birth. The average age of the species is unknown, but individuals as old as 32 years have been banded across New Zealand.
274:
beaches, estuaries and shorelines. They prefer sandy coastal areas and avoid gravel beaches and boulder strewn areas. They nest on the shore between rocks or on sand dunes by making a scrape out of the sand or shingle, sometimes lined with some seaweed.
780:
346:
coastal birds provide some additional resources for the oystercatchers as well. The species has increased in population over the past several generations and is expected to continue rising.
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was shot for food by humans which saw a significant drop in numbers. Adult birds are preyed on by mammalian predators such as possums, cats and dogs. Nest and chick predators are mainly
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862:) during handling: first record of this phenomenon in wild birds, and a global checklist of Haematopus cestode parasites".
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588:
858:
Presswell, B.; Melville, D.S.; Randhawa, H.S. (2012). "Tapeworm bolus expelled from New
Zealand variable oystercatcher (
350:
has the national conservation status of "At Risk, Recovering" but is regarded as being "Regionally
Vulnerable" in the
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Their preferred habitat is a wide range of coastal habitat types varying depending on activity and habitat available.
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individuals range from 42 to 47 cm from beak to tail and have a short, sturdy body with a thick neck.
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partners. After breeding they may be seen within flocks, or on the edges of flocks, of black and white
79:
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714:. Vol. 2, Raptors to lapwings. Melbourne, Victoria: Oxford University Press. pp. 748–756.
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Allison, F.R. (2000). "Cestodes and trematodes from the New
Zealand pied oystercatcher
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A baseline survey of the indigenous bird values of the
Wellington region coastline
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Weekes, P.J. (1982). "Checklist of helminth parasites of birds in New
Zealand".
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McArthur, Nikki; Ray, Samantha; Crowe, Patrick; Bell, Mike (August 2019).
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The Field Guide to the Birds of New
Zealand Volume 2 Raptors to lapwings
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226:. The Māori name is tōrea-pango. They are also known as 'red bills'.
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Variables can be identified as they are slightly larger than the
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When in flight they make a high pitched 'kleep kleep' sound.
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Handbook of Australian, New Zealand & Antarctic Birds
626:"Conservation Assessment of the Variable Oystercatcher
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Martens, and the New Zealand variable oystercatcher
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560:Explore Ta Ara: The encyclopedia of New Zealand
545:National Geographic Complete Birds of the World
492:"Variable Oystercatcher (Haematopus unicolor)"
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699:Marchant, S.; Higgins, P.J., eds. (1993).
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602:
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527:. Wellington: Te Papa Press. p. 210.
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316:Variable oystercatcher feeding its chicks
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522:
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463:"Variable Oyster Catcher - Fact Sheet"
1273:Taxa named by Johann Reinhold Forster
925:
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525:Checklist of the Birds of New Zealand
1152:b2189936-ad6c-4481-b7bd-84c91a8317cd
741:
551:
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1253:IUCN Red List least concern species
623:
424:IUCN Red List of Threatened Species
13:
547:. National Geographic. p. 96.
358:Predators, parasites, and diseases
308:Black variant oystercatcher chicks
14:
1284:
902:
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814:Records of the Canterbury Museum
659:. Oxford University Press. 2005.
78:
806:Haematopus ostralegus finchsii
786:from the original on 2021-01-04
754:from the original on 2021-01-04
744:"Wading Birds - Oystercatchers"
591:from the original on 2021-01-04
585:An Encyclopaedia of New Zealand
413:BirdLife International (2016).
336:
331:South Island pied oystercatcher
252:South Island pied oystercatcher
845:10.1080/03014223.1982.10423876
833:New Zealand Journal of Zoology
229:
1:
579:McLintock, A.H., ed. (1966).
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341:Throughout its entire range,
1263:Endemic birds of New Zealand
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7:
634:International Wader Studies
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876:10.1007/s00436-012-2992-9
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75:Scientific classification
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431:: e.T22693651A93417021.
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258:Distribution and habitat
1268:Birds described in 1844
705:Variable Oystercatcher"
24:Variable oystercatcher
1142:variable-oystercatcher
779:(Report). p. 22.
673:. Penguin Books. 2005.
523:Turbott, E.G. (1990).
317:
309:
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202:variable oystercatcher
1199:Paleobiology Database
864:Parasitology Research
467:Awana Catchment Trust
315:
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245:
917:at Wikimedia Commons
1230:Haematopus-unicolor
965:Haematopus unicolor
935:Haematopus unicolor
915:Haematopus unicolor
860:Haematopus unicolor
810:Haematopus unicolor
703:Haematopus unicolor
628:Haematopus unicolor
496:New Zealand Animals
417:Haematopus unicolor
364:Haematopus unicolor
271:Haematopus unicolor
263:Haematopus unicolor
207:Haematopus unicolor
184:Haematopus unicolor
45:Conservation status
543:Harris, T (2009).
380:Australian magpies
318:
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248:
210:) is a species of
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1186:Open Tree of Life
927:Taxon identifiers
913:Media related to
721:978-0-19-553069-8
394:Taenia increscens
352:Wellington region
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1075:iNaturalist
959:Wikispecies
444:11 November
348:H. unicolor
343:H. unicolor
230:Description
224:New Zealand
1258:Haematopus
1247:Categories
1225:Xeno-canto
812:Forster".
790:2020-01-19
758:2019-05-08
640:: 182–190.
595:2019-05-08
506:2019-05-05
477:2019-05-05
400:References
368:kelp gulls
153:Haematopus
389:mustelids
278:Behaviour
160:Species:
98:Kingdom:
92:Eukaryota
1119:22693651
1093:10591155
992:22693651
987:BirdLife
944:Wikidata
892:16270214
884:22752698
820:: 51–54.
781:Archived
752:Archived
589:Archived
300:Breeding
218:. It is
138:Family:
112:Chordata
108:Phylum:
102:Animalia
88:Domain:
65:IUCN 3.1
1067:2480266
1054:1049059
1041:varoys1
1015:varoys1
974:Avibase
950:Q974671
291:Feeding
220:endemic
191:Forster
148:Genus:
128:Order:
118:Class:
63: (
1217:366770
1204:143800
1178:366770
1149:NZOR:
1139:NZBO:
1132:458153
1106:560354
890:
882:
748:Te Ara
718:
193:, 1844
1212:WoRMS
1191:80079
1165:72962
1088:IRMNG
1036:eBird
1028:3J8XT
1012:BOW:
1005:69726
888:S2CID
784:(PDF)
777:(PDF)
708:(PDF)
384:skuas
283:Voice
212:wader
1173:OBIS
1127:NCBI
1114:IUCN
1101:ITIS
1080:4848
1062:GBIF
1000:BOLD
880:PMID
716:ISBN
446:2021
429:2016
200:The
122:Aves
1049:EoL
1023:CoL
872:doi
868:111
841:doi
433:doi
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