Swamp Harrier

Overview

The swamp harrier (Circus approximans), also known as the Australasian marsh harrier, is a large, slim bird of prey widely distributed across Australasia. In New Zealand, where it is also known as the kāhu, it arrived within the last 700 years and replaced the extinct Eyles's harrier.

Identification

• Largely dark brown plumage that becomes lighter with age, featuring a distinct white rump.
• Body length ranges from 48 to 62 cm, with a wingspan of 118 to 145 cm.
• Adults weigh between 580 and 1,100 g, with females significantly larger than males.
• Flies slowly and low to the ground on upswept wings while hunting.

Habitat

Widespread through Australasia and many islands in the south-west Pacific, including most of Australia except arid regions, New Zealand, Fiji, and Vanuatu. It is usually found in wetlands and well-watered open country, and has benefited from European settlement to become very common in open farmland in New Zealand.

Diet

Mainly feeds on ground birds, waterbirds, rabbits, other small mammals, reptiles, frogs, and fish. During winter months, they feed extensively on carrion, including roadkill, and frequently fall victim to vehicles themselves.

Did you know?

The swamp harrier is the only bird of prey used for falconry in New Zealand, where its quarry is usually pūkeko and young rabbits.