Difference between revisions of "Western marsh harrier"
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==Description== | ==Description== | ||
| − | The western marsh harrier is | + | The western marsh harrier is the largest of the harriers of the genus ''Circus''; about 17 to 25 inches in length and a wingspan of 45 to 51 inches. Males weigh 14 to 23 ounces, while females weigh 18 to 28 ounces. |
The larger and heavier female is consistently dark brown in color overall. The upper head and the throat are a pale yellowish cream to yellow. A dark line encircles the eye, runs to the back of the head. Underneath it bears extensive brown streaks on the chest and belly; to a lesser degree this extends to the underwing coverts. Primaries and secondaries are a brownish-grey, with the tips of the primaries slightly darker in color. In the rust-brown male, the underside streaks give way to more white on the underwing coverts, with much of the remainder of the wing a silver-gray to white; the primaries are black. The tail is long and gray, the head light gray with dark dashes. | The larger and heavier female is consistently dark brown in color overall. The upper head and the throat are a pale yellowish cream to yellow. A dark line encircles the eye, runs to the back of the head. Underneath it bears extensive brown streaks on the chest and belly; to a lesser degree this extends to the underwing coverts. Primaries and secondaries are a brownish-grey, with the tips of the primaries slightly darker in color. In the rust-brown male, the underside streaks give way to more white on the underwing coverts, with much of the remainder of the wing a silver-gray to white; the primaries are black. The tail is long and gray, the head light gray with dark dashes. | ||
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*''Circus aeruginosus harterti''; Africa: Morocco to Tunisia | *''Circus aeruginosus harterti''; Africa: Morocco to Tunisia | ||
| + | ==Diet== | ||
| + | The western marsh harrier is more closely tied to the wetlands than other harriers. It prefers to hunt above the reed belt, also finding prey in dunes and meadows, and is increasingly being seen hunting on farmland. | ||
| + | |||
| + | The harrier's strategy is to surprise its prey in the low search flight, taking the prey usually close to the ground, rarely on the water or in the air. The prey is comprised of some 70-80% of songbirds and (mostly young) waterfowl, in addition to chicks in the nest or eggs. They also hunt mammals such as field mice, brown rats, ground squirrels, young rabbits and rabbits and muskrat (a high percentage of small mammals are taken in farmland habitats<ref>https://www.tandfonline.com/doi/full/10.1080/00063657.2011.648165</ref>), as well as fish, frogs, lizards and large insects. The western marsh harrier has also been seen to chase away other birds from a kill, in addition to scavenging carrion when available. | ||
| + | |||
| + | ==Reproduction== | ||
| + | The nest is usually built in dense reeds above the water or between marsh plants directly on the ground. Nests are sometimes planted in agricultural fields, but rarely in meadows. The same nesting place is reused by some couples. The nest is a large pile of sticks, old reeds and similar material, and constructed almost exclusively by the female. | ||
| + | |||
| + | One clutch is laid per year. In Central Europe, nesting takes place from the beginning of May and can last until June. The typical clutch comprises four to five eggs, to as many as eight. The eggs bear a slight bluish or greenish tint when laid, which later turns to a normal white. Only the female, which is fed by the male at this time<ref>https://scialert.net/fulltextmobile/?doi=ijzr.2006.169.177</ref>, incubates the eggs. The incubation period is 31 to 36 days. | ||
| + | |||
| + | During the first seven to ten days after hatching, the young birds are intensely fed by the female. As they increase in age both parents hunt and feed them. The nestlings are fully feathered at 21 to 28 days and are airworthy by the 35th to 40th day, leaving the nest after another month. | ||
| + | |||
| + | ==Threats== | ||
| + | Since the end of the 19th century, the western marsh harrier was decimated by shooting, egg robbing and destruction of habitat for human development. Since the early 1970s, however, the stock has increased, attributed to the year-round protection and a ban on the use of the pesticide DDT. The species is still threatened by progressive drainage of wetlands, and by disturbances of nesting areas by humans. The pressure put on the bird, despite the increase in numbers, has led to a colonization of agricultural lands<ref>https://www.researchgate.net/publication/233178952_Feeding_behaviour_and_diet_composition_of_Marsh_Harriers_Circus_aeruginosus_in_agricultural_landscapes</ref>, arid areas, and in low elevations within mountain ranges to about 2,500 feet elevation. Another benefit the harriers have taken advantage of, albeit human-caused, is the installation of reservoirs in lowlands and the cleaning up of coastal areas. | ||
| + | |||
| + | The threat can also be reversed. It has been noted that marsh harrier nests have been identified as a source for several species of fungi that are pathogenic to both humans and animals<ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5775078/</ref>. | ||
==References== | ==References== | ||
Latest revision as of 14:34, March 10, 2019
| Western Marsh Harrier | |
|---|---|
| |
| Scientific classification | |
| Kingdom Information | |
| Domain | Eukaryota |
| Kingdom | Animalia |
| Subkingdom | Bilateria |
| Branch | Deuterostomia |
| Phylum Information | |
| Phylum | Chordata |
| Sub-phylum | Vertebrata |
| Infraphylum | Gnathostomata |
| Class Information | |
| Superclass | Tetrapoda |
| Class | Aves |
| Sub-class | Neornithes |
| Infra-class | Neoaves |
| Order Information | |
| Order | Accipitriformes |
| Sub-order | Accipitres |
| Family Information | |
| Superfamily | Accipitroidea |
| Family | Accipitridae |
| Sub-family | Circinae |
| Genus Information | |
| Genus | Circus |
| Species Information | |
| Species | C. aeruginosus |
| Population statistics | |
| Conservation status | Least concern[1] |
The western, or Eurasian marsh harrier, or simply marsh harrier (Circus aeruginosus) is a Palearctic species of bird of prey of family Accipitridae, and found over much of Europe, Asia, and north Africa.
Description
The western marsh harrier is the largest of the harriers of the genus Circus; about 17 to 25 inches in length and a wingspan of 45 to 51 inches. Males weigh 14 to 23 ounces, while females weigh 18 to 28 ounces.
The larger and heavier female is consistently dark brown in color overall. The upper head and the throat are a pale yellowish cream to yellow. A dark line encircles the eye, runs to the back of the head. Underneath it bears extensive brown streaks on the chest and belly; to a lesser degree this extends to the underwing coverts. Primaries and secondaries are a brownish-grey, with the tips of the primaries slightly darker in color. In the rust-brown male, the underside streaks give way to more white on the underwing coverts, with much of the remainder of the wing a silver-gray to white; the primaries are black. The tail is long and gray, the head light gray with dark dashes.
The western marsh harrier holds the wings in a "V" shape while in flight.
Subspecies
- Circus aeruginosus aeruginosus; western and central Palearctic of Europe and Asia (breeding range); sub-Saharan Africa to northern South Africa, and southern Asia (winter range)
- Circus aeruginosus harterti; Africa: Morocco to Tunisia
Diet
The western marsh harrier is more closely tied to the wetlands than other harriers. It prefers to hunt above the reed belt, also finding prey in dunes and meadows, and is increasingly being seen hunting on farmland.
The harrier's strategy is to surprise its prey in the low search flight, taking the prey usually close to the ground, rarely on the water or in the air. The prey is comprised of some 70-80% of songbirds and (mostly young) waterfowl, in addition to chicks in the nest or eggs. They also hunt mammals such as field mice, brown rats, ground squirrels, young rabbits and rabbits and muskrat (a high percentage of small mammals are taken in farmland habitats[2]), as well as fish, frogs, lizards and large insects. The western marsh harrier has also been seen to chase away other birds from a kill, in addition to scavenging carrion when available.
Reproduction
The nest is usually built in dense reeds above the water or between marsh plants directly on the ground. Nests are sometimes planted in agricultural fields, but rarely in meadows. The same nesting place is reused by some couples. The nest is a large pile of sticks, old reeds and similar material, and constructed almost exclusively by the female.
One clutch is laid per year. In Central Europe, nesting takes place from the beginning of May and can last until June. The typical clutch comprises four to five eggs, to as many as eight. The eggs bear a slight bluish or greenish tint when laid, which later turns to a normal white. Only the female, which is fed by the male at this time[3], incubates the eggs. The incubation period is 31 to 36 days.
During the first seven to ten days after hatching, the young birds are intensely fed by the female. As they increase in age both parents hunt and feed them. The nestlings are fully feathered at 21 to 28 days and are airworthy by the 35th to 40th day, leaving the nest after another month.
Threats
Since the end of the 19th century, the western marsh harrier was decimated by shooting, egg robbing and destruction of habitat for human development. Since the early 1970s, however, the stock has increased, attributed to the year-round protection and a ban on the use of the pesticide DDT. The species is still threatened by progressive drainage of wetlands, and by disturbances of nesting areas by humans. The pressure put on the bird, despite the increase in numbers, has led to a colonization of agricultural lands[4], arid areas, and in low elevations within mountain ranges to about 2,500 feet elevation. Another benefit the harriers have taken advantage of, albeit human-caused, is the installation of reservoirs in lowlands and the cleaning up of coastal areas.
The threat can also be reversed. It has been noted that marsh harrier nests have been identified as a source for several species of fungi that are pathogenic to both humans and animals[5].
References
- ↑ https://www.iucnredlist.org/species/22695344/93503491
- ↑ https://www.tandfonline.com/doi/full/10.1080/00063657.2011.648165
- ↑ https://scialert.net/fulltextmobile/?doi=ijzr.2006.169.177
- ↑ https://www.researchgate.net/publication/233178952_Feeding_behaviour_and_diet_composition_of_Marsh_Harriers_Circus_aeruginosus_in_agricultural_landscapes
- ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5775078/
