Editing Swamp harrier

{{Short description|Species of bird}}
{{Speciesbox
| image = Circus approximans -Hamilton Zoo, New Zealand-8a.jpg
| image_caption = Adult swamp harrier at [[Hamilton Zoo]]
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2017 |title=''Circus approximans'' |volume=2017 |page=e.T22695363A111781121 |doi=10.2305/IUCN.UK.2017-1.RLTS.T22695363A111781121.en |access-date=12 November 2021}}</ref>
| genus = Circus
| parent_authority = 
| species = approximans
| authority = [[Titian Peale|Peale]], 1849
| range_map = Distribution Circus approximans.PNG
}}

The '''swamp harrier''' ('''''Circus approximans'''''), also known as the '''Australasian marsh harrier''' or '''Australasian harrier''', is a large, slim [[bird of prey]] widely distributed across [[Australasia]]. In [[New Zealand]], it is also known by the [[Māori-language|Māori]] name {{lang|mi|kāhu}}. It arrived in New Zealand within the last 700 years, replacing the larger species, the extinct New Zealand endemic [[Eyles's harrier]].

The swamp harrier belongs to the subfamily [[Circinae]] and genus ''Circus'', which are represented worldwide, except Antarctica. The subfamily and genus are derived from the characteristic behaviour of circling flight during courtship and hawking.

==Description==
The swamp harrier is largely dark brown, becoming lighter with age, and has a distinct white rump. It hunts by flying slowly, low to the ground, on upswept wings. The body length is {{convert|48|to|62|cm|in|round=0.5|abbr=on}}, and the wingspan is {{convert|118|to|145|cm|ftin|0|abbr=on}}. The recorded weights of adults range from {{convert|580|to|1100|g|lb|abbr=on}}. Females are significantly larger than the males. In New Zealand, 54 males averaged {{convert|640|g|lb|abbr=on}} and 66 females averaged {{convert|870|g|lb|abbr=on}}.{{Citation needed|date=October 2024}} Going on mean weights and linear measurements, the swamp harrier may be by a slight margin the largest extant species of harrier but it is only marginally larger than some other species, like the marsh harriers and the [[Réunion harrier]].<ref>Ferguson-Lees, J., & Christie, D. A. (2001). ''Raptors of the world''. A&C Black.</ref><ref>Dunning Jr, J. B. (2007). ''CRC Handbook of Avian Body Masses''. CRC Press.</ref><ref>Simpson, K., & Day, N. (1984). ''The Birds of Australia: A Book of Identification: 758 Birds in Colour''. L. O'Neil.</ref>

<gallery widths="200px" heights="200px">
File:Circus approximans - Peter Murrel.jpg|Adult male soaring in flight
File:Circus approximans -Coolart Wetlands, Mornington Peninsula, Australia -flying.jpg|Immature flying in Victoria, Australia
</gallery>

==Distribution and habitat==
The swamp harrier is widespread through Australasia and many islands in the south-west Pacific region, including much of [[Australia]] (except the arid region), New Zealand (where it is common in open country),<ref>{{Cite book|title=The field guide to the birds of New Zealand|last1=Heather|first1=Barrie|last2=Robertson|first2=Hugh|publisher=Penguin|year=2005|isbn=978-0-14-302040-0|location=North Shore, New Zealand|pages=275}}</ref> [[Fiji]], [[Vanuatu]], [[New Caledonia]] and as stragglers on some subantarctic islands.<ref name="ReferenceA">A Guide to Canterbury Museum's Edgar Stead Hall of New Zealand Birds</ref> It is usually found in wetlands and well-watered open country.

The swamp harrier only became established in New Zealand within the last few hundred years, after lowland forests were extensively cleared by the first Polynesian settlers. It is absent from the fossil record.<ref>{{Cite book |last1=Worthy |first1=Trevor H. |title=The lost world of the moa : prehistoric life of New Zealand |last2=Holdaway |first2=Richard N. |date=2002 |publisher=Indiana University Press |isbn=0-253-34034-9 |location=Bloomington |oclc=46634728}}</ref> According to archeological and genetic research, humans arrived in New Zealand no earlier than about 1280, with at least the main settlement period between about 1320 and 1350,<ref>{{Cite journal |last1=Jacomb |first1=C. |last2=Holdaway |first2=R. N. |last3=Allentoft |first3=M. E. |last4=Bunce |first4=M. |last5=Oskam |first5=C. L. |last6=Walter |first6=R. |last7=Brooks |first7=E. |date=2014 |title=High-precision dating and ancient DNA profiling of moa (Aves: Dinornithiformes) eggshell documents a complex feature at Wairau Bar and refines the chronology of New Zealand settlement by Polynesians |url=http://dx.doi.org/10.1016/j.jas.2014.05.023 |journal=Journal of Archaeological Science |volume=50 |pages=24–30 |doi=10.1016/j.jas.2014.05.023 |bibcode=2014JArSc..50...24J |issn=0305-4403|url-access=subscription }}</ref><ref>{{Cite journal |last1=Walter |first1=Richard |last2=Buckley |first2=Hallie |last3=Jacomb |first3=Chris |last4=Matisoo-Smith |first4=Elizabeth |date=2017-12-01 |title=Mass Migration and the Polynesian Settlement of New Zealand |journal=Journal of World Prehistory |language=en |volume=30 |issue=4 |pages=351–376 |doi=10.1007/s10963-017-9110-y |issn=1573-7802|doi-access=free }}</ref> consistent with evidence based on [[Whakapapa|genealogical traditions]].<ref>{{Cite journal |last=Roberton |first=J. B. W. |date=1956 |title=Genealogies as a basis for Maori chronology |journal=Journal of the Polynesian Society |volume=65 |issue=1 |pages=45–54 |url= http://www.jps.auckland.ac.nz/document/Volume_65_1956/Volume_65,_No._1/Genealogies_as_a_basis_for_Maori_chronology,_by_J._B._W._Roberton,_p_45%9654/p1}}</ref><ref>{{Cite journal |last=Te Hurinui |first=Pei |date=1958 |title=Maori genealogies |journal=Journal of the Polynesian Society |volume=67 |issue=2 |pages=162–165 |url= http://jps.auckland.ac.nz/document/Volume_67_1958/Volume_67%2C_No._2/Maori_genealogies%2C_by_Pei_Te_Hurinui%2C_p_162-165/p1}}</ref> The Eyles's harrier (''Circus teauteensis''), a larger [[Harrier (bird)|harrier]] species [[Endemism|endemic]] to New Zealand, became extinct after human settlement. All swamp harrier remains from New Zealand that have been studied in detail are some 1000 years old at most, meaning that they post-date human settlement. There is no evidence for widespread coexistence of swamp and Eyles's harriers in New Zealand. Apparently, despite their considerable differences, the two harriers were still ecologically similar enough to [[Competitive exclusion|competitively exclude]] one another, and only when the endemic Eyles's harrier became extinct could the swamp harrier become established.<ref name=":0" />

The swamp harrier has benefited from European settlement, and is now very common, especially in open farmland.<ref name=":0">Seaton, R.; Galbraith, M.; Hyde, N. 2013. [http://nzbirdsonline.org.nz/species/swamp-harrier Swamp harrier]. ''In'' Miskelly, C.M. (ed.) ''New Zealand Birds Online''. www.nzbirdsonline.org.nz</ref>

==Behaviour==
Common enemies of harriers are [[Australian magpie]]s, [[masked lapwing]]s which dive bomb and [[European starling]]s which mob individuals. They have been known to kill the young of [[New Zealand falcon]]s and have also been heavily blamed and persecuted for killing chickens, pheasants and ducklings. Swamp harriers are the only bird of prey used for falconry in New Zealand.<ref>{{cite web |title=Which Birds Of Prey Are Available To NZ Falconers? |url=https://www.wingspan.co.nz/falconry_falconer_requirements.html |website=wingspan.co.nz |access-date=19 March 2020}}</ref> The quarry is usually [[pūkeko]] and young rabbits.

===Diet===
The swamp harrier mainly feeds on ground birds and [[waterbird]]s, rabbits and other small mammals, [[reptile]]s, frogs, and fish. During the winter months harriers feed to a large extent on carrion, including [[roadkill]], frequently falling victim to vehicles themselves.{{Citation needed|date=October 2024}}

===Breeding===
This species nests on the ground, often in wetlands, on a mound in reeds or other dense vegetation. In some districts they nest in fields of oats or barley.<ref name="ReferenceA"/> The clutch size may range from two to seven, but is usually three or four. The [[Avian incubation|incubation]] period is 31 to 34 days, and is carried out by the female alone. Chicks are fed by both parents, are fully feathered by 28 days and [[fledging]] about 45 days after hatching.{{Citation needed|date=October 2024}}

==Notes==
{{Reflist}}

==References==
* BirdLife International (2006). Species factsheet: ''Circus approximans''. Downloaded from http://www.birdlife.org on 4/12/2006
* Marchant, S.; & Higgins, P. J. (eds.). ''[[Handbook of Australian, New Zealand and Antarctic Birds]]. Vol. 2: Raptors to Lapwings''. Oxford University Press: Melbourne. {{ISBN|0-19-553069-1}}.

==External links==
{{Commons category|Circus approximans}}
{{Wikispecies|Circus approximans}}
* [http://www.wingspan.co.nz/birds_of_prey_native_new_zealand_swamp_harrier.html Wingspan Birds of Prey Trust] - The national centre for the conservation, education and advocacy of birds of prey in New Zealand. Location: Rotorua, NZ

{{Taxonbar|from=Q605827}}
{{Authority control}}

[[Category:Harriers (birds)|swamp harrier]]
[[Category:Diurnal raptors of Australia]]
[[Category:Birds of prey of Oceania]]
[[Category:Birds described in 1848|swamp harrier]]
[[Category:Taxa named by Titian Peale]]