The swamp harrier (''Circus approximans''), also known as the Australasian marsh harrier, Australasian harrier or swamp-hawk, is a large, slim

bird of prey Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predators h ...

widely distributed across

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...

. In

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 also known as the harrier hawk, hawk, or by the

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 ...

name . Its arrival in New Zealand happened within the last 700 years, replacing its

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

, the larger extinct New Zealand endemic Eyles's harrier. The swamp harrier belongs to the sub-family Circinae and genus ''Circus'', which are represented worldwide, except

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

. The sub-family 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 , and the wingspan is . The recorded weights of adults range from . Females are significantly larger than the males. In

, 54 males averaged and 66 females averaged . 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 The Réunion harrier or Réunion marsh harrier (''Circus maillardi'') is a bird of prey belonging to the marsh harrier group of harriers. It is now found only on the Indian Ocean island of Réunion, although fossil material from Mauritius has be ...

. 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

Distribution and habitat

The swamp harrier is widespread through Australasia and many islands in the south-west

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

region, including much of

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

(except the arid region),

(where it is common in open country),

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (french: link=no, République de Vanuatu; bi, Ripablik blong Vanuatu), is an island country located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of no ...

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

and as stragglers on some subantarctic islands. It is usually found in wetlands and well-watered open country. The swamp harrier only became established in

within the last few hundred years, after lowland forests were extensively cleared by the first Polynesian settlers. It is absent from the fossil record. 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, consistent with evidence based on genealogical traditions. The Eyles's harrier (''Circus teauteensis''), a larger harrier species

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, 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 competitively exclude one another, and only when the endemic Eyles's harrier became extinct could the swamp harrier become established. The swamp harrier has benefited from European settlement, and is now very common, especially in open farmland.Seaton, R.; Galbraith, M.; Hyde, N. 2013
Swamp harrier
''In'' Miskelly, C.M. (ed.) ''New Zealand Birds Online''. www.nzbirdsonline.org.nz

Behaviour

Common enemies of harriers are

Australian magpie The Australian magpie (''Gymnorhina tibicen'') is a black and white passerine bird native to Australia and southern New Guinea. Although once considered to be three separate species, it is now considered to be one, with nine recognised subs ...

s, masked lapwings which dive bomb and

European starling The common starling or European starling (''Sturnus vulgaris''), also known simply as the starling in Great Britain and Ireland, is a medium-sized passerine bird in the starling family, Sturnidae. It is about long and has glossy black plumage ...

s which mob individuals. They have been known to kill young

kārearea The New Zealand falcon ( mi, kārearea or ''kāiaia''; ''Falco novaeseelandiae'') is New Zealand's only falcon. Other common names for the bird are Bush Hawk and Sparrow Hawk. It is frequently mistaken for the larger and more common swamp harrie ...

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. The quarry is usually

pukeko The Australasian swamphen (''Porphyrio melanotus'') is a species of swamphen (''Porphyrio'') occurring in eastern Indonesia (the Moluccas, Aru and Kai Islands), Papua New Guinea, Australia and New Zealand. In New Zealand, it is known as the pu ...

and young rabbits.

Diet

The swamp harrier mainly feeds on ground

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s and

waterbird A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...

rabbit Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...

s and other small

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

s, and

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

. During the winter months harriers feed to a large extent on carrion, including

roadkill Roadkill is an animal or animals that have been struck and killed by drivers of motor vehicles on highways. Wildlife-vehicle collisions (WVC) have increasingly been the topic of academic research to understand the causes, and how it can be mi ...

, frequently falling victim to vehicles themselves.

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.A Guide to Canterbury Museum's Edgar Stead Hall of New Zealand Birds The clutch size may range from two to seven, but is usually three or four. The 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 Fledging is the stage in a flying animal's life between hatching or birth and becoming capable of flight. This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnerable c ...

about 45 days after hatching.

Notes

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 The ''Handbook of Australian, New Zealand and Antarctic Birds'', known as ''HANZAB'', is the pre-eminent scientific reference on birds in the region, which includes Australia, New Zealand, Antarctica, and the surrounding ocean and subantarctic ...

. Vol. 2: Raptors to Lapwings''. Oxford University Press: Melbourne. .

External links

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

swamp harrier The swamp harrier (''Circus approximans''), also known as the Australasian marsh harrier, Australasian harrier or swamp-hawk, is a large, slim bird of prey widely distributed across Australasia. In New Zealand it is also known as the harrier haw ...

Diurnal raptors of Australia Birds of prey of Oceania

Taxa named by Titian Peale