Circus approximans

General description: 

The Swamp Harrier is a large slim-bodied raptor (bird of prey), with long slender legs and a long tail, rounded at the tip. It is mainly dark brown above and the white rump is prominent. It has an owl-like face mask. The wings are long and broad, with 5 'fingers' on the wing tips in flight. Females are larger with rufous underparts, while the smaller male is lighter underneath. The legs and eyes are yellow. This species has a slow sailing flight on up-swept wings, flying low over water. It is also known as the Marsh Harrier. Usually silent, but gives high pitched descending whistle in breeding display.

Conservation status: 

Not Threatened.

Diagnostic description: 

The Swamp Harrier is a large slim-bodied raptor (bird of prey), with long slender legs and a long tail, rounded at the tip. It is mainly dark brown above and the white rump is prominent. It has an owl-like face mask. The wings are long and broad, with 5 'fingers' on the wing tips in flight. Females are larger with rufous underparts, while the smaller male is lighter underneath. The legs and eyes are yellow. This species has a slow sailing flight on up-swept wings, flying low over water. It is also known as the Marsh Harrier. Usually silent, but gives high pitched descending whistle in breeding display.

Behaviour: 

Size: 

50-60 cm, 750 g

Phylogeny: 

Taxonomy:

    Circus approximans Peale, 1848, Vanua Levu, Fiji. Has been considered a race of C. aeruginosus, with which it forms superspecies, along with C. ranivorus, C. spilonotus and C. maillardi; separated by plumage. Supposedly larger race gouldi of New Guinea, Australia and New Zealand shown by recent work not to differ. Monotypic. (source: Handbook of the Birds of World)
Distribution: 

Distribution:

    S New Guinea (breeding uncertain), Melanesia, Australia, New Zealand and Polynesia E to Tonga. Introduced to Society Is.
Habitat: 

The Swamp Harrier is found in terrestrial wetlands and open country of tropical and temperate Australia and New Zealand. It is mainly seen in fresh or salt wetlands, often in deep swamps with emergent reeds and over open water. In New Zealand it is more widely found, not just in wetlands.

Trophic strategy: 

Swamp Harriers hunt for birds and eggs, large insects, frogs, reptiles and small mammals up to the size of hares or rabbits. When hunting they 'quarter', which means that they systematically search for prey by gliding low to the ground or water, then drop down on to their quarry. In New Zealand, Swamp Harriers often feed on carrion (dead animals).

Reproduction: 

The nest of the Swamp Harrier is made of straw and grasses, hidden above the water in dense reeds in a swamp or in crops or long grasses near water. They usually nest in single pairs. The female incubates and broods the young, while the male hunts for food. He transfers the food to the female in the air, before she feeds it to the young. Breeding season: September to December Clutch size: Three to six Incubation: 33 days Time in nest: 42 days.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith