Gabelracke

Bestimmung

In the field, these robust, large-headed birds are often perched alone on a tree in a grassy clearing, and are almost unmistakable with their colourful plumage tones. The lilac throat of the nominate subspecies C. c. caudatus deepens into a darker lilac breast. The crown to mantle is olive, and the cheeks and ear coverts a lilac-rufous. In subspecies C. c. lorti however, the crown to mantle is greenish blue instead of olive, and the breast azure. The throat is lilac, and some lilac-throated rollers have a lilac patch or rufous-brown tinges on the lower abdomen. Both subspecies have long, black outermost tail streamers that are absent in juveniles. Lilac-breasted rollers are not sexually dimorphic though males may be slightly larger than females. Juveniles, immatures and adults have the largest alula feather dark blue, but the primary coverts and rest of the alula azure. The proximal half of the remiges are also a brilliant azure, and the distal half black on the inner web, and dark purple blue on the outer webs. Juveniles have the throat and breast rufous-tawny with broad diffuse buffy-white streaks with mauve margins on some feathers. Immatures have the breast buffy with occasional lilac feathers and diffuse pale streaking.<p>The average mass is 104 grams, and length ranges from 36 to 38 centimeters (inclusive of the tail streamer of 8 to 9 cm). These acrobatic fliers have an average wingspan range of 50 to 58 cm. Unique to rollers (family Coraciidae) are syndactyl feet, in which the second and third digits are fused.<p>They may be confused with the sleeker Abyssinian roller in the Turkana Basin of Kenya, which however has dark blue upper tail coverts, an azure breast and distinctly spatulate tail streamers. Besides spatulate tail streamers, pinkish-breasted racket-tailed rollers have darker greater regime coverts and darker blue primary coverts.<p>The call of a lilac-breasted roller is a harsh, sawing "rak rak rak" that is given during flight. Usually, the bird will perch to sing.

Taxonomie

The lilac-breasted roller was formally described by the Swedish naturalist Carl Linnaeus in 1766 in the twelfth edition of his Systema Naturae under the binomial name Coracias caudata. Linnaeus based his description on "Le Rollier d'Angola" that had been described and illustrated in 1760 by the French zoologist Mathurin Jacques Brisson. The specific epithet caudatus is Latin meaning "tailed".<p>The lilac-breasted roller is one of nine species in genus Coracias, a group native to the open woodlands of western Eurasia and Africa.<p>The phylogenetic relationships among the Coracias species are shown below, from the molecular study by Johansson et al. (2018)<p>Two subspecies are recognized: <p>Though not parapatric (their breeding ranges do not meet) there is no evidence of behavioural or ecological differences that would support C. c. lorti as a separate species.

Wissenschaftlicher Name

Coracias caudatus

Autorität

Linnaeus, 1766

Ordnung

Coraciiformes

Familie

G України

Gattung

Coracias

Verbreitung und Lebensraum

Lilac-breasted rollers are found throughout eastern and southern Africa, and occurs locally at sea level, and up to 2,000 metres above sea level or over. Their range extends from the Red Sea coast of Eritrea through East Africa (including Zanzibar) to southern Africa, where they occur commonly in Namibia (excluding the Namib Desert), Botswana, Zimbabwe, and northeastern South Africa. The nominate subspecies C. c. caudatus is non-migratory, but a measure of post-breeding dispersal occurs into miombo woodland or sandy areas, before they return to the breeding areas at the start of the rains. Its counterpart, the lilac-throated roller (C. c. lorti) migrates from northeast Kenya to northwest Somalia to breed from late April to mid-September. The latter subspecies is also a vagrant to Eritrea, Oman and Yemen. Lilac-breasted rollers are most abundant in Kenya, though the species is less abundant than in former times.<p>Both subspecies live in open savannah habitats with scattered trees and shrubs, as the birds require higher perches for feeding and nesting. Less often they frequent riverine vegetation and light forest, and may enter subdesert steppe or open grassland where any elevated perches may be used. In protected areas, lilac-breasted rollers are among the bird species that frequent the verges of roads, especially during fires, when the small animals and insects that emerge from cover are easily predated. However, lilac-breasted rollers avoid other human-influenced areas and are not found in urban or rural areas unless they are abandoned. Outside of protected areas such as national parks, lilac-breasted rollers may infrequently be seen when farmers burn land for agricultural use. Such brush fires stir up insects and other invertebrates, and birds can be seen swooping in for easy prey.

Zugverhalten

Standvogel

Verhalten

Zugverhalten: Standvogel.

Schutzstatus

Bestandstrend: stabil.

Bestandstrend

stabil