Hen Harrier (Circus cyaneus) lives in moorland and open grassland across North America and Eurasia. It feeds on small mammals birds. Its conservation status is Least Concern.
Fascinating facts about the Hen Harrier
- Hen harriers are among the few raptors that practice polygyny, a single male may mate with several females, sometimes up to five in one breeding season. To support multiple broods, a male defends a territory averaging 2.6 km², but some territories stretch from 1.7 km² to a massive 150 km². The extra food provided by a well-fed male can boost the number of females he attracts, showing how resource abundance directly shapes mating systems in this species.
- When hunting, hen harriers glide low with wings in a shallow V, hugging the ground to listen and look for prey. Their diet is astonishingly focused: up to 95 % of what they eat are small mammals, especially voles, but they also snatch passerine birds, shorebirds and even young waterfowl. Larger catches like rabbits are sometimes drowned before being carried off, a technique that highlights their versatile predatory toolkit despite a diet dominated by tiny rodents.
- Hen harriers rarely live past eight years, though the longest-recorded individual reached 16 years and 5 months. Early mortality is high because eggs and nestlings fall prey to badgers, foxes, crows, ravens, dogs and owls. Even adult birds face competition from short-eared owls, which they often harass to steal prey.
- In the UK, hen harriers are teetering on the brink: breeding pairs fell to an estimated 662 in 2010 and only 34 successful nests were recorded in 2022, a stark drop from the capacity for over 300 pairs in England. Between 2004 and 2016 the Scottish population shrank 27 %, and the RSPB reports 102 confirmed or suspected persecution incidents from 2020-2024, making it the most persecuted raptor relative to its numbers. These figures reveal how illegal killing on grouse moors is driving a rapid, human-induced decline.
- At just over half a meter long, the hen harrier stretches a wingspan of up to 1.22 m, yet the sexes differ dramatically in weight: males tip the scales at 290-400 g (average 350 g) while females can weigh 390-750 g (average 530 g).
Sources
Every fact above was checked against these pages, and kept only where one of them states it.
At a glance
RangeNorth America and Eurasia
HabitatMoorland and open grassland
DietSmall mammals birds
About the Hen Harrier
As the sun rises over the heather moors, a ghostly form materializes, the Hen Harrier emerging from the mist like a spectral hunter, its pale wings beating in a slow, deliberate rhythm as it quarters the landscape in search of prey. With a fluid, almost ethereal motion, it glides and banks, its sharp eyes scanning the terrain below for the slightest sign of movement, its very presence a masterclass in patience and stealth. In this fleeting moment, the Hen Harrier embodies the essence of the wild, a symbol of the untamed beauty that still thrives in the most unexpected corners of our world.
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