About Harrier (Bird)

About Harrier (Bird)

  • Harrier, any of about 11 species of hawks of the subfamily Circinae (family Accipitridae).
  • They are plain-looking, long-legged, and long-tailed birds of slender build that cruise low over meadows and marshes looking for mice, snakes, frogs, small birds, and insects.
  • Harriers are about 50 cm (20 inches) long, have small beaks, and their face feathers are arranged in facial discs.
  • They nest in marshes or in tall grass and lay four to six dull whitish or bluish eggs.
  • The best-known harrier is the hen harrier (British), called the northern harrier or marsh hawk in the United States (Circus cyaneus), which breeds in temperate and boreal regions throughout the Northern Hemisphere and in southern South America.
  • Also common are the marsh harrier (C. aeruginosus) and Montagu’s harrier (C. pygargus) ranging over most of Europe and from the Mediterranean shores of North Africa to Mongolia.
  • The pallid harrier (C. macrourus) breeds from the Baltic to southeastern Europe and Central Asia.
  • Allied species include the cinereous harrier (C. cinereus), found from Peru to the Straits of Magellan; the long-winged harrier (C. buffoni), ranging over all of South America, especially east of the Andes; the South African marsh harrier (C. ranivorus), ranging north to Uganda on the east; and the pied harrier (C. melanoleucus), of central eastern Asia.
  • Many of the 14 species in this group, such as the pallid harrier and Montagu’s harrier, are migratory and move to warmer climates for the winter.
  • Some species, such as the African marsh harrier, remain in their breeding territories all year.
  • Every winter, several species of harrier birds travel thousands of kilometres to escape frigid Central Asia for the grasslands of the subcontinent.

 

Highlights of the news

  • The “poorly studied” harrier species is the focus of a study by two researchers from the Ashoka Trust for Research in Ecology and Environment (ATREE), who compared previous records of sightings with more current observations to determine what many had feared.
  • Researchers collated the data on roosting harriers to analyse trends in their population since the mid-1980s.
  • At least five species of harriers were recorded in India over the years; India has one of the largest roosting sites in the world for Pallid Harriers and Montagu’s Harriers.
  • The researchers focused on six of the 15 major roosting sites in six States, where consistent observations had been made for over five years.
  • In the mid-1990s, an estimated 1,000 birds roosted here.
  • By 2016, the number was down to less than 100 birds.
  • While a general declining trend was observed in all the monitored sites, researchers noted the most dramatic changes at the Rollapadu Bustard Sanctuary in Andhra Pradesh’s Kurnool district, one of the largest.
  • In Hessarghatta on the outskirts of Bengaluru, Western Marsh Harriers declined significantly, leaving the area nearly deserted.
  • The importance of area protection can be seen in the number of birds. While there is a median count of 125 harriers in protected areas, it’s less than half that number — 48 — in unprotected areas.
  • However, the study notes that the population of the species in Central Asia has not seen any drastic changes.
  • So, these results indicates possibilities of:
    • The migrant birds have found better places to roost than India, which the researchers think is improbable.
    • Considering the overall decline is spread out, the numbers could signify a lowering trend in populations.
    • Remarked on the possibility of a combination of multiple factors for the fall.

 

 

Possible reasons for decline

  • The gravest concern is the loss of grasslands, either to urbanisation or to agriculture.
  • In February-March, peak season for the arrival of the birds, farmlands are burnt or over-grazed.
  • Of the 15 roosting sites surveyed, eight no longer exist as grasslands, and only five are protected.
  • Excessive use of pesticides in farms in and around the roosting sites could also be a reason for the lowered population counts.
  • In crops such as cotton, the use of pesticides kills grasshoppers, the harriers’ primary prey, and could lead to mortality of the birds themselves as they are on the top of the food chain.

 

Way forward

  • Globally, of the 16 harrier species, only two are listed as endangered by the International Union for Conservation of Nature, even though most of them are declining.
  • Hence, more intensive research on the bird is needed.
  • The conservation of India’s grasslands could be a start in protecting the magnificent migrators.
Section : Environment & Ecology

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