Spotted dwarf bearded
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Spotted dwarf bearded ( Pogoniulus scolopaceus ) |
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| Pogoniulus scolopaceus | ||||||||||
| ( Bonaparte , 1850) |
The spotted dwarf mustard ( Pogoniulus scolopaceus ), also known as the scale dwarf mustard , is a species from the African bearded family. The small and inconspicuously dark colored species occurs in Africa on both sides of the equator. Several subspecies are distinguished. The IUCN classifies the spotted dwarf beardling as not endangered ( least concern ).
features
Appearance and build
The males of the nominate form reach a wing length between 5.2 and 5.5 cm. The tail becomes 3–3.2 cm long. The beak length is 1.28–1.6 cm. The wing length of the females is 5.1–5.6 cm, their tail is 29–32 cm long. The female beak measures 1.38–1.63 mm. There is therefore no noticeable sexual dimorphism with regard to body dimensions. When the gender assignment was unclear, various studies showed a body weight between 11 and 18 g for adult birds.
Both males and females have an olive to black face with fine yellow spots, the top of the head is greenish-black. The top of the body is dark yellowish green. The control feathers are brown with greenish-yellow to yellow edges. The chin and throat are yellowish white. The chest and belly are speckled olive green on a pale yellow background. The upper side of the wings is brown with yellow feather edges, as are the upper wing coverts, which appear scaly or spotty as a result. The underside of the wings is a little lighter brown with wide white-yellow or yellow edges. The bow of the wing is banded black-brown on a yellow background.
The skin around the eyes is dark gray to greenish black. The iris of the eyes is variable in color yellow, yellow-brown or white; at the pupil it is usually darker and fades outwards. The strong beak is matt black; Legs and feet are dark green. Young birds have more yellow on the upper side of the body, but this is paler than in the adult birds. The beak is dull black than in adult individuals and fades into dull yellow at its base.
Vocalizations
The spotted dwarf beard has a repertoire of several calls. A common reputation begins with individual tik , followed by tikik syllables and finally a series of individual tik syllables and series of two to six of these syllables. Also hat-hat- ... - or tok-tok- ... -series (similar to the yellow-fronted tinkerbird ) are common cries of the stain Zwergbärtlings. In addition, the birds emit frog-like nasal sounds, high-pitched Hyet calls and a staccato of short, high ti sounds that increase up to 2.25 kHz.
distribution
The distribution area of the spotted dwarf mustard extends from Sierra Leone and Guinea (including Bioko ) over the south of West Africa to South Cameroon , in the south-east of the Central African Republic and Uganda as well as in the north of Angola and the south-east of the Democratic Republic of the Congo . The western Kenyan deposits are apparently extinct.
habitat
The spotted dwarf beard lives in forests and forest edges, swamp forests , clearings and succession societies in various forms. Also in cultivated landscapes such as cocoa plantations, provided there is enough dead wood for cave construction. The height distribution extends up to 1,800 meters, on Bioko from 50 to 1,000 m.
Way of life
nutrition
While foraging for food, he prefers to stay at a height of 15 to 25 m above the ground. The stand density in Gabon is estimated at 12 to 15 pairs per square kilometer of primary forest and three to five pairs per square kilometer of secondary forest. The food spectrum consists of fruits and insects. Insects are occasionally caught in midair.
Territorial behavior
Spotted dwarf mustaches are territorial birds that defend a territory all year round, the center of which is the nesting hole. The districts have a size of 6 to 8 ha in primary forest, districts in secondary forest are significantly larger with 20–33 ha. The male defends the territory with territory chants.
Reproduction
Breeding pairs of the spotted dwarf beardling sleep together in the breeding cave outside of the breeding season, sometimes in threes. It is at a height of at least half a meter; in Gabon nests were found at 3–8 m, in Liberia at 22 m. The cave opening is extremely narrow at 10 mm, even for a small bird like the spotted dwarf bearded. Often burned to shield trees ( Musanga ) in farmland used for nest building. The clutch consists of 2–4 eggs with a white shell; they measure 17–18.5 × 13.5–14.5 mm.
Sometimes the actual breeding pair is supported by another adult bird in breeding and rearing the young, which tries to obtain food in the same way as the parents. The duration and timing of the breeding season vary depending on the region. While it lasts extremely short in some areas (in Uganda from around December to January and in May), in other parts of the world, spotted dwarf beards breed throughout the year.
Systematics
Three subspecies are usually recognized for the spotted dwarf beardling:
- P. scolopaceus scolopaceus ( Bonaparte , 1850) - The nominate form inhabits Western Africa up to and including Nigeria.
- P. scolopaceus flavisquamatus ( J. Verreaux & E. Verreaux , 1855) - This subspecies is darker in color than the nominate form, it is also slightly larger. Their distribution area includes southern Cameroon to Uganda in the east and the Democratic Republic of the Congo and Angola in the south.
- P. scolopaceus stellatus ( Jardine & Fraser , 1852) - The largest of the three subspecies only inhabits the island of Biolo in the Gulf of Biafra . Their plumage shows less yellow, which is why they appear olive green on the belly side, while the back is lighter than in the other subspecies.
supporting documents
literature
- Lester L. Short, Jennifer FM Horne: Toucans, Barbets and Honeyguides - Ramphastidae, Capitonidae and Indicatoridae. Oxford University Press, Oxford 2001, ISBN 0-19-854666-1 .
Individual evidence
Web links
- Pogoniulus scolopaceus inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved February 2, 2014.