| Spotted harrier | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Accipitriformes |
| Family: | Accipitridae |
| Genus: | Circus |
| Species: | C. assimilis |
| Binomial name | |
| Circus assimilis | |
 | |
| range [2] strongholds year-round distribution non-breeding distribution | |
The spotted harrier (Circus assimilis) also known as the smoke hawk, is a large Australasian bird of prey belonging to the family Accipitridae.
The spotted harrier belongs to the family Accipitridae. Accipitridae is the largest family in the order Accipitriformes and encompasses many of the diurnal birds of prey including hawks and eagles. It is one of the largest avian families with 233 species in 67 genera included in the family worldwide. [3]
The spotted harrier is a medium-sized, slender bird of prey with adult females reaching 58–61 cm. Both adults and juvenile birds have an owl-like facial ruff that creates the appearance of a short, broad head as well as long yellow legs. The spotted harrier's wings feature prominent black tips and the tail is prominently barred and slightly wedge shaped.
Adult males are much smaller than the females only growing to 50–55 cm. Adult birds have blue to grey upper parts with a chestnut face and underparts that feature numerous white spots. Juvenile birds in their first year of life are mostly a dark brown and buff on their upperparts with pale buff underparts that feature brown streaks across the chest and stomach. During the second year of their life the spotted harrier takes on almost adult colouring with white streaks across their underparts instead of the prominent spots that can be seen on adults. [4]
The spotted harrier is native to Australia and Indonesia, however vagrant populations have been seen in Timor-Leste. It has a geographic range of more than 20,000km2 (Birdlife International, 2012). Spotted harriers can be seen throughout most of Australia's mainland, except in densely forested or woodland habitats of the coast, escarpments and ranges, and rarely in Tasmania. In NSW individuals are widely dispersed, comprising a single population. [5]
The spotted harrier is a terrestrial bird residing in open grasslands, open woodland including acacia and mallee, inland riparian woodland, grassland and shrubland. It can be most commonly found in native grassland however it is also seen in agricultural land and inland wetlands for the purpose of foraging. [5]
The spotted harrier is a carnivorous bird of prey feeding mostly on terrestrial mammals such as bandicoots, bettongs and rodents as well as small birds and reptiles and occasionally large insects. Formerly the species was heavily dependent on rabbits however the rapid spread of rabbit calicivirus disease led to a significant decline in rabbit numbers in arid and semi arid zones (by up to 65-85%). Due to this the spotted harrier is increasingly dependent of native prey however many of its former native mammalian prey species are extinct in inland NSW and many of its remaining key prey species such as terrestrial grassland birds are threatened by grazing as they require ground cover and are sensitive to habitat degradation. The spotted harrier soars with elevated wings when hunting. [5]
A stick nest built in a tree is the method of choice for the spotted harrier. They reproduce in spring or sometimes autumn laying a clutch of 2–4 eggs. The incubation period is 33 days with young remaining in the nest for several months from hatching. The spotted harriers generation length is estimated to be 10 years. [5]
Due to its extremely large range, and its large and stable population, the spotted harrier has been designated as a species of least concern by the International Union for Conservation of Nature. [1]
The species was included in a NSW population survey in 1977-81 which used 75 one degree grids to find bird population numbers. The spotted harrier recorded at mostly moderate to high reporting rates (11-40% and more than 40% of surveys per grid, respectively). Breeding was recorded in 14 of these grids. A repeat of this survey was performed in 1998-2002 which found that spotted harrier numbers had declined (less than 20% of surveys per grid), with breeding in only 6 grids. This suggests that a statewide decline of 70% over 3 generations (30 years) will occur. One issue with this study is that due to the large distribution of the spotted harrier this study only covers a small sample of the entire species, misrepresenting the species as a whole. Also it is known that there are many threatening processes occurring in NSW that are affecting populations on a large scale basis that are not happening as prolifically in other areas. This study should be performed through the whole distribution of the species to find and accurate summary of the species population status. This study does however accurately represent populations in NSW and therefore a management plan can be put in place to manage numbers in this state alone. [5]
The spotted harrier is mostly threatened by clearing and degradation of suitable foraging and breeding habitat. These threats also extend to key prey species affecting prey densities. Clearing and grazing of breeding sites are a key threat alongside secondary poisoning from rodenticides and pindone, a poison used in the control of rabbits. [5]
Clearing of native vegetation' is listed as a Key Threatening Process in NSW under the Threatened Species Conservation Act 1995. Clearing has affected important bioregions on the NSW western slopes and plains which once contained high harrier breeding densities. Since the 1980s clearing has wiped 40-84% of these bioregions. 85-91% of these bioregions have also been affected by grazing. The landscape of these regions have also found to be highly stressed, most areas falling into landscape stress factor categories of 2–6 out of 6. More westerly NSW bioregions have also found to be heavily grazed and have landscape stress ratings of 3–4 from 6. [5]
A harrier is any of the several species of diurnal hawks sometimes placed in the subfamily Circinae of the bird of prey family Accipitridae. Harriers characteristically hunt by flying low over open ground, feeding on small mammals, reptiles, or birds. The young of the species are sometimes referred to as ring-tail harriers. They are distinctive with long wings, a long narrow tail, the slow and low flight over grasslands and skull peculiarities. The harriers are thought to have diversified with the expansion of grasslands and the emergence of C4 grasses about 6 to 8 million years ago during the Late Miocene and Pliocene.
Goobang is a national park located in New South Wales, Australia, 296 kilometres (184 mi) northwest of Sydney. It protects the largest remnant forest and woodland in the central west region of the state, where interior and coastal New South Wales flora and fauna species overlap. Originally named Herveys Range by John Oxley in 1817, the area was reserved in 1897 as state forest because of its importance as a timber resource, and was designated a national park in 1995.
The hen harrier is a bird of prey. It breeds in Eurasia. The term "hen harrier" refers to its former habit of preying on free-ranging fowl.
Montagu's harrier (Circus pygargus) is a migratory bird of prey of the harrier family. Its common name commemorates the British naturalist George Montagu.
The Pallid Harrier is a migratory bird of prey of the harrier subfamily. The scientific name is derived from the Ancient Greek. Circus is from kirkos, referring to a bird of prey named for its circling flight, probably the hen harrier and macrourus is "long-tailed", from makros, "long" and -ouros "-tailed".
The eastern marsh harrier is a bird of prey belonging to the marsh harrier group of harriers. It was previously considered to be conspecific with the western marsh harrier but is now usually classified as a separate species. It has two subspecies: C. s. spilonotus in eastern Asia and C. s. spilothorax in New Guinea.
The little eagle is a very small eagle endemic to Australia.
The black-chested snake eagle or black-breasted snake eagle is a large African bird of prey of the family Accipitridae. It resembles other snake eagles and was formerly considered conspecific with the short-toed and Beaudouin's snake eagles, to which it is closely related.
The Japanese sparrowhawk is a bird of prey in the family Accipitridae which also includes many other diurnal raptors such as eagles, buzzards and harriers. The bird is known by many alternative names such as the Japanese lesser, Asiatic, or Eastern sparrowhawk. This species is a small raptor with broader and rounder wings and a shorter tail. Its total length measures 23–30 centimetres (9.1–11.8 in). It has a dark back and whitish underside with brown-grey barring and red-brown colouring on the sides in males, and with heavier brown barring on the abdomen in females. Both sexes have a stripe across the throat, but its more obvious in the female. Is it typically identified by its appearance, but occasionally produces a chattering kiki-kik-kik... sound. This species generally breeds in parts of Russia, Korea, Japan, and China. There are three subspecies of Japanese sparrowhawk that differ by distribution and appearance. The species is globally listed as least concern, although it is listed as endangered in Japan and protected in China.
The letter-winged kite is a small, rare and irruptive bird of prey that is found only in Australia. Measuring around 35 cm (14 in) in length with a wingspan of 84–100 cm (33–39 in), the adult letter-winged kite has predominantly pale grey and white plumage and prominent black rings around its red eyes. Its name derives from its highly distinctive black underwing pattern of a shallow 'M' or 'W' shape, visible when in flight. This distinguishes it from the otherwise similar black-shouldered kite. This species is also the only nocturnal species within the order Accipitriformes despite few differences found in its visual anatomy to other closely related kites.
The grey falcon is a medium-sized falcon native to Australia, possibly the rarest. It is uncommon throughout its range and is currently classified as Vulnerable.
The Papuan harrier is a bird of prey native to New Guinea which belongs to the harrier genus Circus. It was classified as a subspecies of the eastern marsh harrier of eastern Asia.
The Réunion harrier, also known as Réunion marsh harrier, is a species of bird of prey belonging to the marsh harrier group of harriers. It is now found only on the Indian Ocean island of Réunion, although fossil material from Mauritius has been referred to this species. It is known locally as the papangue or pied jaune. The Malagasy harrier of Madagascar and the Comoro Islands was previously treated as a subspecies of this bird but is increasingly regarded as a separate species. The Réunion harrier appears to be declining in numbers and it is classed as an endangered species.
The African marsh harrier is a bird of prey belonging to the harrier genus Circus. It is largely resident in wetland habitats in southern, central and eastern Africa from South Africa north to South Sudan.
The Forrest's mouse, or desert short-tailed mouse, is a small species of rodent in the family Muridae. It is a widespread but sparsely distributed species found across arid and semi-arid inland Australia, commonly found in tussock grassland, chenopod shrubland, and mulga or savannah woodlands.
The little sparrowhawk is a species of Afrotropical bird of prey in the family Accipitridae. It is the smallest member of the genus Accipiter and forms a superspecies with the red-thighed sparrowhawk.
The long-winged harrier is a common bird of prey species endemic to South America. They are members of the family Accipitridae, under the genus Circus which encompasses other harrier species. Its range encompasses most of South America, in grassland and wetland all across the continent. The long-winged harrier is a carnivorous bird, and will feed on many different animals found in its habitat. Like owls and other harrier species, the long-winged harrier has a distinctive facial disc, which is used to triangulate the bird's hearing while it is hunting.
The spotted nightjar or spotted eared-nightjar is a species of nightjar in the family Caprimulgidae. It inhabits much of mainland Australia and has also been found in several Indonesian islands. Its natural habitats are open forests and woodlands, scrub, spinifex and tussock grassland, savannah woodland and mangroves.
The ground cuckoo-shrike is an uncommon bird species endemic to Australia, occurring mainly in open woodland and arid grasslands throughout inland Australia, but also occasionally in areas on the east coast.
The variable hawk is a polymorphic species of bird of prey in the family Accipitridae.
Media related to Circus assimilis at Wikimedia Commons
