Marsh harrier

It hunts small mammals, frogs, fish, insects and birds, surprising them as it drifts low over fields and reedbeds.

Like all marsh harriers, it favours open, wet environments, and is frequently seen drifting low over rice fields, interspersing long, watchful circling glides with two or three slow, powerful wingbeats.

Two subspecies are recognised: C. s. spilonotus of east Asia, and C. s. spilothorax, of New Guinea and the islands nearby, which is sometimes thought to be a separate species and is often called the Papuan harrier.

The swamp harrier (C. approximans) at about 50 to 58 cm is slightly larger than C. spilonotus, often a little darker, and has less heavily barred wings and tail.

It is commonly found in suitable habitat anywhere in Australasia, particularly in the higher rainfall areas to the east, south-east, and south-west, of Australia and throughout New Zealand, but also in the tropical north of Australia and the island groups of New Caledonia, Vanuatu, Fiji, Tonga and the Society Islands.

The African marsh harrier (C. ranivorus) is a distinct non-migratory species that has not usually been included as a subspecies of C. aeruginosus.