River moorhen
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River moorhen |
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| Systematics | ||||||||||||
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| Porzana fluminea | ||||||||||||
| Gould , 1843 |
The river moorhen ( Porzana fluminea ) is a species of railing that belongs to the genus of the moorhen . It is a small, short-tailed species of rail with a short, powerful beak that belongs exclusively to the avifauna of Australia .
The stock situation of the river marsh grouse is given as harmless ( least concern ). No subspecies are distinguished.
Appearance
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The river moorhen reaches a body length of 19 to 23 centimeters, of which 4.6 to 5.8 centimeters are on the tail. The wing measures 8.8 to 10.8 centimeters. The beak length is 1.9 to 2.2 centimeters. The males weigh an average of 65 grams, the females are slightly lighter at 55 grams. There is little gender dimorphism .
male
Forehead, over-eye stripes, face and throat are dark gray, in some individuals there are also fine white dots or fine white spots on the ear covers . The crown of the head, the nape of the neck and the back of the neck are brownish olive in color with black and white dashes. The rest of the upper side of the body has the same color and has white and dark brown spots and narrow white and darker feather edges.
The underside of the body is dark gray with fine white spots on the neck and chest sides. The flanks, belly sides and rump are cross-banded in black and white. The under tail-coverts are white. The beak is light green to olive yellow, the iris is bright red. The legs and feet are greenish to olive yellow.
female
Females are slightly duller colored on the upper side of the body and have a stronger olive-brown tone. On the sides of the chest and on the throat they are a little more spotted white.
Fledglings
Young birds are colored similarly to the adult birds on the upper side of the body, but the white spots are not as pronounced in them. They are usually completely absent on the upper tail-coverts and the rump. The face and forehead are olive brown with more intense white spots than that of the adult birds. The chin and throat are gray with white spots or white with darker speckles. The parts of the body that are cross-banded black and white in the adult birds are still cross-banded diffusely brown-white in them. The belly is usually whitish. The iris is still dark brown.
Possible confusion
It can be confused with the pygmy moorhen , which also belongs to the marsh fowl genus. This is more intensely cinnamon colored on the top of the body. The South Sea Moorhen is darker and does not have as noticeable color markings as the River Moorhen. The Krickrale also has no white markings. Compared to this species, the river moorhen is slightly smaller, more compact and has a shorter neck, a longer tail, a short, strong green beak, and greenish legs and feet.
Distribution area and habitat
The river moorhen occurs exclusively on the Australian mainland, on Tasmania and a few offshore islands. The main area of distribution is the south-east and south-west of Australia. The river moorhen is only found sporadically in other regions.
In the Australian state of Queensland, the distribution area extends from Booby Island along the East Australian coast to the Brisbane region. However, the range is disjoint . In New South Wales the species is also rare and limited to some coastal regions. In Victoria , on the other hand, the river moorhen is common, while it is very rare in Tasmania and limited to the eastern half of this island. In South Australia the river moorhen is also limited to the east and occurs mainly north of 30 ° south latitude. In Western Australia , the main area of distribution is south of Perth and in Kimberley , in the Northern Territory it is mainly found in the region around Alice Springs . The migratory movements of the river marsh grouse have so far been little investigated, but individual observations suggest that they migrate from regions during longer dry seasons.
The habitat of the river moorhen are the fringes of wetlands. It occurs in tidal and salt marshes, in river mouths, on swamps, rivers, lakes, billabongs and lagoons. It mainly inhabits the dense bank vegetation. However, it is considered a species that is less dependent on dense bank vegetation compared to the South Sea Moorhen.
Way of life
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The river moorhen lives solitary and in pairs, only rarely in small groups. It is an inconspicuous bird that is less shy compared to other railings. It is able to swim and dive, but only covers short distances in this way. It rarely flies up, the flight seems strained and fluttering, with the legs and feet hanging down. While foraging for food, it seldom strays far from the protective cover and goes to it immediately if something disturbs it.
The river moorhen eats seeds, mollusks, insects, crustaceans and spiders. It is diurnal, but can mainly be seen in the early morning and late evening hours while foraging for food.
Reproduction
The breeding biology of the river marsh grouse has so far been little studied. The breeding season generally falls between August and January, although the river moorhens that occur in western Australia breed a little earlier. The nest is built in the dense vegetation on the banks. The clutch usually consists of four to five eggs, which are believed to be laid by the female 24 hours apart. Both parent birds breed. Since the nestlings hatch asynchronously, it is assumed that they begin incubating before the clutch is complete. In one observed case, seven chicks hatched over a period of five days. The chicks flee the nest . They are led by both parent birds.
Predators
The predators of the river moorhen include cats and dogs, the common tiger otters and various species of birds of prey. Presumably belonging Egrets to the predators of this Rallenart.
literature
- PJ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds , Volume 2, Raptors to Lapwings, Oxford University Press, Oxford 1993, ISBN 0-19-553069-1 .
Web links
Individual evidence
- ↑ Handbook of the Birds of the World on the River Moorhen, accessed May 30, 2017.
- ↑ a b c Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds . Volume 2, p. 551.
- ↑ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds . Volume 2, p. 556.
- ↑ a b c Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds . Volume 2, p. 552.
- ↑ a b Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds . Volume 2, p. 553.
- ↑ a b c Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds . Volume 2, p. 555.