Black harrier

Filed under: Raptors & Bird of Prey |

Globally Vulnerable, Endangered in Namibia and Near-threatened in South Africa. Outside of protected areas it is largely reliant on the remnants of natural vegetation in agricultural land.

Among South Africa’s rarest breeding endemics, the Black Harrier Circus maurus  has a global population of only about 1500 birds. It breeds only in South Africa, where its breeding grounds are centred on the coastal and montane regions of the Western Cape.
Over the last 9 years, FitzPatrick Institute researchers and students have studied its breeding requirements. After monitoring 150 nesting sites and over 250 breeding attempts we understand these requirements well.
Black Harriers breed most successfully in protected coastal areas where mouse numbers are high. Under such conditions, pairs raise on average two young per breeding attempt. The least successful breeding occurs in mountainous areas, where more than half of all nests fail and the average nest produces
only one fledgling. The reason for its rarity is shrinking habitats.  More than 90% of the Cape lowlands have been transformed by agriculture. After breeding, many harriers move away from the breeding grounds, but we know not where. We also have no information about how many of them die (and why) during the non-breeding season. A successful pilot tracking study in 2008 has shown some unusual behaviours, such as regular night-time activity and, during the breeding season, foraging much farther from the nest (30-50 km) than previously appreciated.

This striking bird of prey breeds in the unique and incredibly diverse fynbos habitat of South Africa; a habitat which is threatened by the activities of humans. Adult black harriers have black plumage with bold white stripes across the tail, a white rump, and conspicuous white wing panels. Females are larger than males, and juveniles can be distinguished by their dark brown plumage, which is heavily mottled and streaked. The genus name of the black harrier, Circus, refers to the male’s circling, acrobatic flight display, undertaken to impress a female during courtship.

 

Movements and migrations

Largely resident, although it tends to head north and east from the Western Cape in winter.

Food

It mainly eats mice and birds, doing most of its hunting on blustery days. It flies close to the ground, then speedily drops onto its prey, often giving chase on the ground before finishing the animal off. The following food items have been recorded in its diet:

  • birds
    • Coturnix coturnix (Common quail)
  • rodents
  • reptiles
  • amphibians
  • insects
  • carrion

Breeding

  • Typically a monogamous solitary nester, although a single male may mate with multiple females (a practice known as polygyny). It occasionally forms loose colonies, with nests spaced about 50-100m apart.
  • Males vigorously defend their territory: in one case, a male locked its talons with another male and they cart-wheeled to the ground, after which they continued to fight. A few weeks later, one of them was found dead from head wounds sustained from the fight.
  • The male often displays over a potential display site, flying up and down in a U-shaped pattern, calling at the top of each undulation; this acts as both a territorial and a courtship display. Once a female starts following him, he finishes off with a spectacular looping flight close to the ground, before descending to the potential nest site.
  • The nest is a small platform of stems, grass and small twigs, typically placed on or near the ground in dense marsh grass tufts or near fynbos bushes and sedges. It especially favours nest sites alongside a small stream.
  • Egg-laying season is from June-November, peaking in September.
  • It lays 1-5, usually 3 eggs, which are solely incubated by the female for roughly 34 days, while the male regularly feeds her at the nest.
  • The chicks are cared for intensely by the female for the first few weeks of their lives, feeding them with food provisioned by the male. At four weeks old, the chicks start to hide in the vegetation surrounding the nest, leaving completely at about 36-41 days old and becoming fully independent at least two weeks later.

 

http://www.fitzpatrick.uct.ac.za/pdf/Project_BlackHarrier.pdf

http://www.biodiversityexplorer.org/birds/accipitridae/circus_maurus.htm

http://sabap2.adu.org.za/docs/sabap1/168.pdf

Leave a Reply

Your email address will not be published. Required fields are marked *

seventeen − four =

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>