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Hen harrier

size:

43-50 centimeters
wingspan: 100-120 centimeters

color (adults):

males: mainly grey back, blue belly with grey upper chest, white rump, black-winged tips; females: brown back, white ring around upper tail

food:

small rodents (mice, rats, young rabbits and hares) and birds (pheasants, meadow birds and songbirds)

threats:

decline in suitable open landscapes

Dutch status:

nesting bird (96% on Wadden Islands); birds from the north migrate through the Netherlands

habitat

dunes, fields of heather, marshes, fallow fields

reproduction:

3-5 eggs; maturity 2 years

life span:

7 years (maximum known age:+ 17 years)

  • Dut: Blauwe Kiekendief
  • Eng: Hen Harrier
  • Fren: Busard Saint-Martin
  • Ger: Kornweihe
  • Ital: Albanella reale
  • Lat: Circus cyaneus
  • Dan: Bli kærhøg
  • Nor: Myrhauk
  • Frisian: Blauwe Hoanskrobber
Hen harrier, female, foto fitis, adriaan dijksen

Hen harrier

Do you ever see a hen harrier in the Netherlands? Then you are very fortunate! These beautiful birds are having a very difficult time surviving in this country. They are only found in just a few places and their numbers keep dropping. It is unknown why this is happening, but is probably due to a lack of food and a decline in their breeding grounds. Just like the marsh harrier, hen harriers have a shallow V-shaped sillouette as they scan the ground for prey or glide low over the ground.

On Texel


Hen harrier, foto fitis, sytske dijksen

Prior to 1980, hen harriers did not nest on Texel. In those days, it were Montagu's harriers that nested here! Since 1980, hen harriers increased in population on the island, reaching a peak in 1994 with 27 pairs. However the numbers have been declining since then and by 2010, there were only 8 pairs of this rare raptor still nesting here.

  • Nesting harriers

    The hen harrier builds its nest on the ground in a field of heather or a dune slack. That isn't always the safest place. In 2009, two nests were plundered by thieves on Terschelling. Five young disappeared from one nest and three eggs were removed from the other one. There was an obvious path made by people that led to the nests.

    When there is sufficient food around, it is not unusual for males to have multiple females,. However, there is often a ranking system among the females. Number one female gets the best treatment and is therefore the most successful.

  • Population developments in the Wadden Sea region
    Hen harrier, foto fitis, adriaan dijksen

    The first nesting pair of hen harriers in the wadden region was on Ameland in 1940. The population in the wadden region reached a peak between 1990-1994, when 115 pairs were counted. This accounted for 90% of the total Dutch population of hen harriers. In 2008, there were only 29 pairs on the Wadden islands, of which 11 on Texel, compared to a total of 36 the year before. By 2009, there weren't any hen harriers breeding on Ameland anymore. Hen harriers are listed on the Red List as threatened bird species.

  • Reasons for decline

    It is unknown why the hen harrier population is declining in the Netherlands, although a recent study on Terschelling and Ameland offers suggestions. When compared to a study made in the 1970s, the content of pellets has changed from larger to smaller animals. While pheasants, meadow birds and rabbits used to make up a large portion of the menu, the majority of prey is now made up of mice and voles. Perhaps these birds are having problems because they need to catch smaller prey. But it could also be a question of migration. Hen harrier populations on the German Wadden Islands are growing. Using colored rings, bird experts are trying to discover whether Dutch harriers have moved to Germany. They already know that it happens to some degree.  A female that nested on Baltrum in 2009 had been ringed three years before at birth on Schiermonnikoog.

  • Protection
    • Monitoring: Network Ecological Monitoring, Red List
    • Policy: Target Species List, Species Protective Plans
    • National legislation: Flora and Fauna Regulation
    • European Agreement: Bird Directive, CITES ordinance
    • International: Bern Convention, Bonn Convention