The hen harrier (Circus cyaneus) is a bird of prey. It breeds in open areas such as marshes and grasslands in Eurasia and is migratory, moving further south outside of the breeding season. Birds in milder regions, such as France and Great Britain, may be resident year-round, but the higher altitudes are largely deserted in winter. The species is sexually dimorphic; males are smaller and mostly grey and white with black wingtips, whereas females average larger and are predominantly brown and have buff underparts with brown barring. Both sexes have a white rump patch, although it is more noticeable on females and juveniles.

The term "hen harrier" refers to its former habit of preying on free-ranging fowl. The northern harrier (Circus hudsonius) was formerly considered to be a subspecies of the hen harrier.

Taxonomy

In 1758 the English naturalist George Edwards included an illustration and a description of the hen harrier in the first volume of his Gleanings of Natural History. He used the English name "The blue hawk". Edwards based his hand-coloured etching on a bird that had been shot near London. When in 1766 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the twelfth edition, he placed the hen harrier with the falcons and eagles in the genus Falco. Linnaeus included a brief description, coined the binomial name Falco cyaneus and cited Edwards' work. The hen harrier is now placed in the genus Circus that was introduced by the French naturalist Bernard Germain de Lacépède in 1799. The genus name Circus is derived from the Ancient Greek kirkos, referring to a bird of prey named for its circling flight (kirkos, "circle"). The specific epithet cyaneus is from Latin and means "dark blue". The species is monotypic: no subspecies are recognised.

Description

thumb|240px|left|Female soaring in [[Pangolakha Wildlife Sanctuary, India]]

thumb|right|Bird in flight at an elevation of over 12,500 ft in [[Pangolakha Wildlife Sanctuary in East Sikkim district, India in the month of November]]

thumb|right|Adult male in flight in [[Langholm, Scotland]]

The hen harrier is

The female gives a whistled piih-eh when receiving food from the male, and her alarm call is chit-it-it-it-it-et-it. The male calls chek-chek-chek, with a more bouncing chuk-uk-uk-uk during his display flight.

The nest is constructed on the ground or on a mound of dirt or vegetation. Nests are made of sticks and are lined inside with grass and leaves. Four to eight (exceptionally 2 to 10) whitish eggs are laid. The eggs measure approximately . The eggs are incubated mostly by the female for 31 to 32 days. When incubating eggs, the female sits on the nest while the male hunts and brings food to her and the chicks. The male will help feed chicks after they hatch, but does not usually watch them for a greater period of time than around 5 minutes. Larger prey, such as rabbits and adult ducks are taken sometimes and harriers have been known to subdue these by drowning them in water. The hen harrier is on the British red list. There is sufficient suitable habitat to support over 300 breeding pairs of hen harriers in England alone, yet only 34 successful nests were recorded in 2022. Furthermore, many of the young birds do not survive beyond their first year, before the onset of sexual maturity at the age of two. Most UK Hen Harriers are found in Scotland, but even there the population declined by 27% between 2004 and 2016.

Relationship with humans

In some parts of Europe people believed that seeing a hen harrier perched on a house was a sign that three people would die. Unlike many raptors, hen harriers have historically been looked upon favourably by farmers because they eat predators of quail eggs and mice that damage crops. Harriers are sometimes called "good hawks" because they do not pose a threat to poultry as some hawks do. In the United Kingdom, hen harriers include red grouse in their diet, and so harriers are regarded by some people as pests. This may lead to birds being shot or trapped, and eggs and nests being destroyed. According to the RSPB, the hen harrier is the most persecuted bird of prey in the UK relative to population size as of 2025, with 102 confirmed and suspected persecution incidents between 2020 and 2024.

Forestry and hen harriers

thumb|Eggs, Collection [[Museum Wiesbaden]]

The hen harrier is a bird of open habitats such as heather moorland and extensive agricultural land. However, much of its range, particularly in Ireland and parts of western Britain, has been (and continues to be) afforested, mainly with non-native conifers such as Sitka spruce (Picea sitchensis) from North America.

  • The Langholm Moor Demonstration Project
  • Field Guide Page on Flickr
  • Range in Iran (in Persian)
  • Ageing and sexing (PDF; 4.3 MB) by Javier Blasco-Zumeta & Gerd-Michael Heinze
  • RSPB Skydancer website
  • Save The Skydancer page on BirdWatchIreland.ie