The African Marsh-harrier
, Circus ranivorus
, is endemic to southern, central and eastern Africa. It is usually found in wetland areas, especially those with reeds, but also occurs in grassland and farmland. Where wetlands have been degraded, drained or converted to agricultural land the bird has disappeared. Its population may naturally fluctuate in core areas as rodent populations fluctuate with rainfall.
They forage outside the wetland habitat over drier flood plains, grasslands and agricultural grain fields hunting striped mice, other small mammals and birds. They occasionally hunt over open water or over the canopy of woodland and may scavenge on dead fish.
The African Marsh-harrier is celebrated for their aerial food passes. The male calls softly as they approach incubating or brooding females. The female flies under the prey-carrying male and catches the prey in mid-air. Prey is missed only 4% of the time!
They cover large distances during foraging; up to 200 km for as much as half of the daylight hours when fending for demanding nestlings. Large view
The Marsh-harrier is a monogamous breeder. Their favoured breeding habitat includes the large reed beds which fringe lakes or floodplains. Mate fidelity is high - pairs tend to stay together and often retain the same territory and nest in the same general location year after year. In South Africa September seems to be the peak egg-laying month. Ultimately, the breeding season is timed such that peak nestling demands coincide with peak prey availability and prey intake.
Eggs are laid at widely varying intervals, the average of 2 to 3 days apart and 2 to 5 eggs (average 3) are produced.
Young hatch with white down, pink skin and eyes initially closed. Asynchronous hatching is common with the first 2 young often hatching within 1 day of each other or together, last hatchlings are sometimes up to 8 days behind. The last chicks are first to succumb if food becomes scarce.
Time until independence is up to three months after hatching, when parents stop feeding young but do not drive them from their territory. Flying young gradually begin hunting on their own while waiting for ever-decreasing food provisioning.