African crake
African crake | |
---|---|
On the Zaagkuildrift Road, South Africa | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Gruiformes |
Family: | Rallidae |
Genus: | Crecopsis Sharpe, 1893 |
Species: | C. egregia
|
Binomial name | |
Crecopsis egregia (Peters, W, 1854)
| |
Breeding summer visitor (ranges are very approximate)
Resident year-round | |
Synonyms | |
Ortygometra egregia |
The African crake (Crecopsis egregia) is a small- to medium-size ground-living bird in the rail family, found in most of central to southern Africa. It is seasonally common in most of its range other than the rainforests and areas that have low annual rainfall. This crake is a partial migrant, moving away from the equator as soon as the rains provide sufficient grass cover to allow it to breed elsewhere. There have been a few records of vagrant birds reaching Atlantic islands. This species nests in a wide variety of grassland types, and agricultural land with tall crops may also be used.
A smallish crake, the African crake has brown-streaked blackish upperparts, bluish-grey underparts and black-and-white barring on the flanks and belly. It has a stubby red bill, red eyes, and a white line from the bill to above the eye. It is smaller than the
The African crake feeds on a wide range of
Taxonomy
The
Richard Bowdler Sharpe considered that the African bird differed sufficiently from the corn crake to have its own genus Crecopsis, and later authors sometimes placed it in Porzana, based on a resemblance to the ash-throated crake, P. albicollis. Structural differences rule out Porzana, and the placement in Crex became the most common and best-supported treatment,[5][6] until the International Ornithological Committee (IOC) 2020 world bird list moved the crake back to Crecopsis. This followed research that showed that the African crake was most closely related to the Rouget's rail, rather than the corn crake.[7][8]
The genus name Crecopsis is derived from Crex and the Ancient Greek opsis "appearance",[9] and the species name egregia derives from Latin egregius, "outstanding, prominent".[10]
Description
The African crake is a smallish crake, 20–23 cm (7.9–9.1 in) long with a 40–42 cm (16–17 in) wingspan. The male has blackish upperparts streaked with olive-brown, apart from the nape and hindneck which are plain pale brown; there is a white streak from the base of the bill to above the eye. The sides of the head, foreneck, throat and breast are bluish-grey, the flight feathers are dark brown, and the flanks and sides of the belly are barred black and white. The eye is red, the bill is reddish, and the legs and feet are light brown or grey. The sexes are similar in appearance, although the female is slightly smaller and duller than the male, with a less contrasting head pattern. Immature birds have darker and duller upperparts than the adult, a dark bill, grey eye, and less barring on the underparts. There are no subspecific or other geographical variations in plumage. This crake has a complete moult after breeding, mainly prior to migration.[2] Although this species occurs in fairly open habitats, it lacks the pure white undertail used for signalling in open water or gregarious species like the coots and moorhens.[11]
The African crake is smaller than the corn crake, which also has darker upperparts, a plain grey face and different underparts barring pattern. In flight, the African species has shorter, blunter wings with a less prominent white leading edge and deeper wingbeats than its relatives. Other sympatric crakes are smaller with white markings on the upperparts, different underparts patterns and a shorter bill. The African rail has dark brown upperparts, a long red bill and red legs and feet.[2]
Voice
Like other rails, this species has a wide range of vocalisations. The male's territorial and advertising call is a series of rapid grating krrr notes repeated two or three times a second for several minutes. It is given most often in the breeding season, usually early or late in the day, but sometimes continues after dark or starts before dawn. The male stands upright with his neck extended when advertising, but will also call when chasing intruders on the ground or in flight. Both sexes give a sharp, loud kip call as an alarm or during territorial interactions, adapting a similar pose as for the advertising call. Once breeding starts, the birds become much quieter, but territorial birds commence the kip call again during the non-breeding season, especially when there is a high density of African crakes in the area. A wheezy kraaa is associated with threat displays and copulation; imitation of this call by a human can bring a rail to within 10 m (33 ft). Newly hatched chicks make a soft wheeeez call, and older chicks cheep.[2]
The rasping advertising call is readily distinguished from the hwitt-hwitt-hwitt of spotted crake, the monotonous clockwork tak-tak-tak-tak-tak of striped crake, or the quick-quick of Baillon's crake.[12] The corn crake is silent in Africa.[13]
Distribution and habitat
The African crake occurs throughout sub-Saharan Africa from Senegal east to Kenya, and south to
This crake is a partial migrant, but although it is less skulking than many of its relatives, its movements are complex and poorly studied; the distribution map is therefore largely hypothetical. It is mainly a wet-season breeder, and many birds move away from the equator as soon as the rains provide sufficient grass cover to allow them to breed elsewhere. Southward movement is mainly from November to April, the return north beginning when burning or drought reduces the grass cover again. This species is present throughout the year in some West African countries, and in equatorial regions, but even in those areas numbers vary seasonally due to local movements; north-south migration has been noted within countries including Nigeria, Senegal, The Gambia, Ivory Coast and Cameroon.[2] Migration involves small groups of up to eight birds.[1] It may be one or two months after the rains begin before the grass is sufficiently high for breeding birds to arrive. Even in southern Africa, some birds may stay after breeding if enough usable habitat remains.[15]
The habitat is predominantly grassland, ranging from wetland edges and seasonal marshes to savanna, lightly wooded dry grassland, and grassy forest clearings. The crake also frequents corn, rice and cotton fields, derelict farmland and sugarcane plantations close to water. A wide range of grass species are used, with a preferred height of 0.3–1 m (0.98–3.28 ft) tall but vegetation is acceptable up to 2 m (6.6 ft) tall. It normally prefers moister and shorter grassland habitats than does the corn crake, and its breeding territories often contain or are close to thickets or termite mounds. It occurs from sea level to 2,000 m (6,600 ft) but is rare in the higher altitude grasslands. Its grassland habitat is frequently burned in the dry season, forcing the birds to move elsewhere.[2] In an East African study, the average area occupied by one bird was 2.6 hectares (6.4 acres) when breeding, and 1.97 to 2.73 ha (4.9 to 6.7 acres) at other times.[21] The highest densities occur in lush or moist grassland such as the Okavango Delta.[15]
Behaviour
The African crake is active during the day, especially at dusk, during light rain, or after heavier rain. It is less skulking and easier to flush from cover than other crakes, and is often seen at the edges of roads and tracks. An observer in a vehicle can approach to within 1 m (3.3 ft). When a bird is flushed it normally flies less than 50 m (160 ft), but new arrivals may occasionally fly twice as far. A flushed crake will frequently land in a wet area or behind a thicket, and crouch on landing. In short grass, it can escape from a dog using its speed and manoeuvrability, running with the body held almost horizontal. It may roost in a depression near grass tussock and it will bathe in puddles.[2]
The African crake is territorial on both the breeding and non-breeding grounds; the male threat display involves the bird standing upright and spreading the feathers of the flanks and belly like a fan to show the barred underparts. He may march towards the intruder, or walk side by side with another displaying male. The female may accompany the male, but with feathers less widely fanned. Fighting at territorial boundaries involves the male birds jumping at each other and pecking. Paired females will attack other females in the territory, especially if the male has shown an interest in them.[2]
Breeding
Breeding behavior commences with a courtship chase with the female running in a crouch, pursued by the male, who adopts a more upright stance and has his neck outstretched. The female may stop and lower her head and tail to allow copulation; this takes just a few seconds, but may be repeated several times in an hour. The nest is a shallow cup of grass leaves, sometimes with a loose canopy, built in a depression and hidden under a grass tussock or small bush; it may be on dry ground or slightly raised above standing water, or occasionally floating. The nest is about 20 cm (7.9 in) across with the internal cup 2–5 cm (0.79–1.97 in) deep, and 11–12 cm (4.3–4.7 in) wide. The
Feeding
The African crake feeds on
Predators and parasites
Predators include the leopard,[26] serval, cats, the black-headed heron, dark chanting goshawk, African hawk-eagle and Wahlberg's eagle.[2] In South Africa, newly hatched chicks were taken by a boomslang.[27] If surprised, an African crake will leap vertically into the air before running away, a tactic believed to help it to evade snakes or terrestrial mammals.[28]
Parasites of this species include ticks of the family Ixodidae,[29][30] and a feather mite, Metanalges elongatus, of the subspecies M. e. curtus. The nominate form of the mite occurs thousands of kilometres away in New Caledonia.[31]
Status
The African crake has a huge breeding range estimated at 11,700,000 km2 (4,500,000 mi2). Its population is unknown, but it is common in most of its range, and its numbers appear to be stable. It is therefore classed as
Although most rails in the Old World are covered by the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA), the African crake is not listed even in Kenya, where it is considered "near-threatened". Like its relative, the corn crake, it is too terrestrial to be classed as a wetland species.[32]
References
- ^ . Retrieved 14 February 2022.
- ^ a b c d e f g h i j k l m n Taylor & van Perlo (2000) pp. 316–320
- ^ Peters, James Lee (1934). Check-list of birds of the World. Volume 2. Cambridge, Massachusetts: Harvard University Press. p. 181.
- ^ Bechstein, Johann Matthäus (1803). Ornithologisches Taschenbuch von und für Deutschland oder kurze Beschreibung aller Vogel Deutschlands, vol 2 (in German). Leipzig: Richter. p. 336.
- ^ Taylor & van Perlo (2000) p. 30
- ^ Livezey (1998) p. 2098
- ^ "IOC World Bird List version 10.2:Flufftails, finfoots, rails, trumpeters, cranes, limpkin". IOC. Retrieved 30 November 2020.
- .
- ISBN 978-1-4081-2501-4.
- ISBN 0-550-10185-3.
- S2CID 44487493.
- ISBN 1-86872-735-1.
- ISBN 0-00-219204-7.
- .
- ^ a b c Taylor P B. "African Crake" (PDF). Southern African Bird Atlas Project. Animal Demography Unit (Department of Zoology, University of Cape Town), BirdLife South Africa, South African National Biodiversity Institute. Retrieved 26 May 2011
- ^ Larison, Brenda; Smith, Thomas B; Milá, Borja; Stauffer, Donald; Nguema, José (1999) " Bird and Mammal Surveys of Rio Muni" pp. 9–57 in Larison, Brenda; et al. (1999). Biotic Surveys of Bioko and Rio Muni, Equatorial Guinea (PDF) (Report). Archived from the original (PDF) on 2011-07-20. Retrieved 2011-05-20.
- ^ de Juana, Eduardo; El Comité de Rarezas de la Sociedad Española de Ornitología (2003). "Observaciones de aves raras en España, 2001" (PDF). Ardeola (in Spanish). 50 (1): 123–149.
- ^ Amadon, Dean (1953). "Avian systematics and evolution in the Gulf of Guinea: The J. G. Corrleia collection" (PDF). Bulletin of the American Museum of Natural History. 100 (3): 393–452.
- ^ Peter, Joris; Pöllath, Nadja (2002) "Holocene faunas of the Eastern Sahara: zoogeographical and palaeoecological aspects" pp. 34–51 in Albarella, Umberto; Dobney, Keith; Rowley-Conwy, Peter, eds. (2002). Proceedings of the 9th Conference of the International Council of Archaeozoology, Durham, August 2002 (PDF).
- ^ Gautier, Achiel (1998). "Animals and people in the Holocene of North Africa". ArchaeoZoologia. 9 (1/2): 1–181.
- .
- ^ Sclater, W L (1906). The Birds of South Africa. Volume 4. London: R H Porter. pp. 248–249.
- .
- .
- ^ Taylor & van Perlo (2000) pp. 39–41
- ^ Hill, R A (2001). "Leopard cub kills crake". CCA Ecological Journal. 3: 63.
- .
- ^ Taylor & van Perlo (2000) p. 44
- ^ Elbl, Alena; Anastos, George (1966). Ixodid ticks (Acarina, Ixodidae) of Central Africa, Volume 4. Tervuren, Belgium: Musée royal de l'Afrique centrale. p. 58.
- .
- ^ Zumpt, Fritz (1961). The Arthropod Parasites of Vertebrates in Africa South of the Sahara (Ethiopian Region), Volume 1: Chelicerata. Johannesburg: South African Institute for Medical Research. pp. 200–201.
- ^ Ng'weno, Fleur; Matiku, Paul; Mwangi, Solomon, eds. (1999). Kenya and the African-Eurasian Waterbird Agreement (AEWA). Nairobi: NatureKenya. pp. 16–17. Archived from the original on 2014-09-03.
Cited texts
- Livezey, Bradley C (1998). "A phylogenetic analysis of the Gruiformes (Aves) based on morphological characters, with an emphasis on the rails (Rallidae)". Philosophical Transactions of the Royal Society of London. 353 (378): 2077–2151. PMC 1692427.
- Taylor, Barry; van Perlo, Berl (2000). Rails. Robertsbridge, Sussex: Pica. ISBN 1-873403-59-3.
External links
- Videos, photos and sound recordings at the Internet Bird Collection
- African Crake. The Atlas of Southern African Birds.
- BirdLife International 2012. Crex egregia. The IUCN Red List of Threatened Species. Version 2014.3. Downloaded on 9 April 2015.