No.041 · Birds · Uncommon
Marsh harrier
Circus aeruginosus
The biggest of the British harriers glides low over the reeds with wings held in a shallow V, quartering for prey. Males sky-dance in spring.
When to see a marsh harrier
All year, mostly at dawn, by day and at dusk.
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Time of day
- Dawn
- Day
- Dusk
- Night
Where to see a marsh harrier in the UK
- The Norfolk Broads. Quartering the reeds and marshes around Hickling and Horsey; East Anglia is one of the species' strongholds.
Marsh harrier facts at a glance
- Best time
- Day, all year; best March–June for sky-dancing and food passes over the reeds.
- Where in the game
- the Norfolk Broads (reedbed, fen and grazing marsh)
- Size
- Length 48–55 cm (Wildlife Trusts)
- Wingspan
- About 1.2 m (Wildlife Trusts)
- Weight
- About 600 g (BTO mean 602 g)
- Lifespan
- Oldest ringed bird 13 years 3 months (BTO); breeding birds average around 6 years
- Population
- About 590 pairs (BTO, 2016); RSPB now says around 700 pairs
- Status
- Amber (Birds of Conservation Concern 5, 2021)
Diet
Small waterbirds, young coots and moorhens, small mammals, frogs and eggs
Habitat
Reedbeds for nesting; hunts over reed, fen, grazing marsh and farmland
Breeding
Nests on the ground in reed; clutch 4–5 eggs, incubation 31–38 days; young fledge after 35–40 days.
Field signs
- Long, low glides over reeds with wings raised in a shallow V and wobbling side to side
- Males are brown above and chestnut beneath with grey, black-tipped wings; females are chocolate brown with a creamy or golden crown and throat
- A mobbing flock of lapwings or gulls rising from the marsh
Did you know?
- Marsh harriers were driven extinct in Britain by persecution in the 19th century, and were down to a single pair in Suffolk in 1971 (RSPB, BTO).
- In spring the male sky-dances, tumbling towards the ground before swooping back up (RSPB).
- Food passes: the male drops prey from the air and the female flips over to catch it beneath him.
Moments worth waiting for
- Sky-dance
A male climbs high, folds and tumbles towards the reeds before swooping up again. - Food pass
The male carries prey over the nest; the female rises, rolls and takes it mid-air.
Photo tip
Park at a viewing spot with the sun behind you and follow a bird along the reedbed edge; use continuous autofocus with a 400–600 mm lens and 1/2000 s for in-flight shots.
Be a good naturalist
Marsh harriers are Schedule 1 birds. Never approach nests, keep to public paths and hides, and never flush a bird to make it fly.
The law
Schedule 1 of the Wildlife and Countryside Act 1981: illegal to intentionally or recklessly disturb at or near the nest.
