Lilac-breasted roller

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Lilac-breasted roller
Lilac-breasted roller (Coracias caudatus) Kruger.jpg
Kruger National Park, South Africa
Recording of a bird calling in flight
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Coraciiformes
Family: Coraciidae
Genus: Coracias
Species:
C. caudatus
Binomial name
Coracias caudatus
Linnaeus, 1766
Coracias caudatus dist.jpg
  resident range
Synonyms
  • Coracias caudataLinnaeus, 1766 ( lapsus )

The lilac-breasted roller (Coracias caudatus) is an African bird of the roller family, Coraciidae. It is widely distributed in Southern and Eastern Africa, and is a vagrant to the southern Arabian Peninsula. [1] It prefers open woodland and savanna, and it is for the most part absent from treeless places. Usually found alone or in pairs, it perches at the tops of trees, poles or other high vantage points from where it can spot insects, amphibians and small birds moving about on the ground. [2] Nesting takes place in a natural hole in a tree where a clutch of 2–4 eggs are laid, and incubated by both parents, who are extremely aggressive in defence of their nest, taking on raptors and other birds. During the breeding season the male will rise to a fair height (69 to 144 metres), descending in swoops and dives, [3] while uttering harsh, discordant cries. The sexes do not differ in coloration, and juveniles lack the long tail streamers of adults. This species is unofficially considered the national bird of Kenya. Alternative names for the lilac-breasted roller include the fork-tailed roller, lilac-throated roller (also used for a subspecies of purple roller) and Mosilikatze's roller.

Contents

Taxonomy and systematics

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. [4] Linnaeus based his description on "Le Rollier d'Angola" that had been described and illustrated in 1760 by the French zoologist Mathurin Jacques Brisson. [5] The specific epithet caudatus is Latin meaning "tailed". [6]

The lilac-breasted roller is one of nine species in genus Coracias , a group native to the open woodlands of western Eurasia and Africa.

The phylogenetic relationships among the Coracias species are shown below, from the molecular study by Johansson et al. (2018) [7]

Coracias

Blue-bellied rollerC. cyanogaster

Purple rollerC. naevius

Racket-tailed rollerC. spatulatus

Indian rollerC. benghalensis

Indochinese rollerC. affinis

Purple-winged rollerC. temminckii

Lilac-breasted rollerC. caudatus

Abyssinian rollerC. abyssinicus

European rollerC. garrulus

Two subspecies are recognized: [8]

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. [9]

Description

Adult bird perched at a lookout in Chobe National Park, Botswana Lilac-breasted roller (Coracias caudatus caudatus) Botswana.jpg
Adult bird perched at a lookout in Chobe National Park, Botswana

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. [3] Both subspecies have long, black outermost tail streamers that are absent in juveniles. Lilac-breasted rollers are not sexually dimorphic [3] 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. [10] Juveniles have the throat and breast rufous-tawny with broad diffuse buffy-white streaks with mauve margins on some feathers. [11] Immatures have the breast buffy with occasional lilac feathers and diffuse pale streaking. [10]

The average mass is 104 grams, and length ranges from 36 to 38 centimeters (inclusive of the tail streamer of 8 to 9 cm). [9] [3] These acrobatic fliers have an average wingspan range of 50 to 58 cm. [12] Unique to rollers (family Coraciidae) are syndactyl feet, in which the second and third digits are fused. [13]

They may be confused with the sleeker Abyssinian roller in the Turkana Basin of Kenya, [14] 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.

Vocalizations

The call of a lilac-breasted roller is a harsh, sawing "rak rak rak" that is given during flight. [3] Usually, the bird will perch to sing. [15]

Distribution and habitat

With orthopteran prey in Etosha National Park, Namibia Coracias caudatus 2 MHNT.jpg
With orthopteran prey in Etosha National Park, Namibia

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 [11] [16] or over. [10] 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. [10] 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. [1] Lilac-breasted rollers are most abundant in Kenya, [3] though the species is less abundant than in former times. [11]

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 [10] or open grassland where any elevated perches may be used. [9] 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. [17] 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. [18] Such brush fires stir up insects and other invertebrates, and birds can be seen swooping in for easy prey.

Behaviour and ecology

Breeding

Juvenile bird at Samburu National Reserve in central Kenya - it has rufous-tawny chest plumage, and its outer rectrices lack the streamers of adult plumage. Flickr - Rainbirder - Lilac-breasted Roller (Coracias caudatus) (1).jpg
Juvenile bird at Samburu National Reserve in central Kenya – it has rufous-tawny chest plumage, and its outer rectrices lack the streamers of adult plumage.

Both subspecies are probably monogamous and nest solitary. [10] The sexes are not readily distinguishable, and their displays have not been definitively linked to either male or female. Pairs are protective of their nest and one of the pair will fly in a rolling pattern as a territorial display against intruders or to detract nest predators. During courtship, a lilac-breasted roller will fly upwards and then tip forward with the wings closed, before flapping to gain speed towards the ground. [3] While leveling out at highest speed the bird will roll to the left and right a few times, uttering a harsh, raucous "kaaa, kaarsh", [10] before swooping up again. The display may end with a harsh chuckling. [11] If another male enters another territorial ground, they are presume to be rivals and would fight one another by thrusting, beating each others wings, and claw one another while flying upwards.

Lilac-throated rollers breed from late April to mid-September in Somalia, while lilac-breasted rollers breed at various times of the year, depending on the location. They build flat nests of grass in a baobab, dead coconut, casuarina or Terminalia tree. [3] The nest is situated in a hollowed out tree cavity some 5 meters (16 ft) off the ground, or even in the side of a termite mound. Lilac-breasted rollers do not create the cavities themselves, but take over nest spaces that have been previously hollowed out by woodpeckers or kingfishers.

Typically, lilac-breasted rollers in Somalia will lay three to four eggs per breeding season. In southern Africa, the average clutch size ranges from two to four eggs. Male and female partners will take turns incubating the eggs for 22 to 24 days. [12] Hatchlings are born altricial, becoming fully feathered after 19 days.

Feeding

The diet of the lilac-breasted roller consists of arthropods and small vertebrates, including ground-dwelling insects, spiders, scorpions, centipedes and millipedes, snails, and a variety of small vertebrates, including small birds. Slow-moving lizards, chameleons and snakes, and the blind, burrowing Afrotyphlops and Leptotyphlops species are especially vulnerable to them when crossing roads. [17] In East Africa, they join other perch hunters like Taita fiscals and pale flycatchers to make opportunistic use of grassland fires, [19] and in South Africa are likewise seen in association with kites, storks, swallows and bee-eaters when burning of firebreaks drives small animals unto roads. [17]

Because they feed mainly on terrestrial prey, lilac-breasted rollers will perch to scout from a higher vantage point (including from atop of large herbivorous mammals [20] ) before swooping in and grabbing prey with their beaks. If their prey is small, they will swallow it on the ground. These aggressive birds will carry larger prey back to a perch and beat it until it is dismembered. [3]

Status

According to the International Union for Conservation of Nature and Natural Resources (IUCN), the lilac-breasted roller is of least concern. The large range and stable population size contribute to this assessment. [1]

Related Research Articles

<span class="mw-page-title-main">Coraciidae</span> Family of birds

Coraciidae is a family of Old World birds, which are known as rollers because of the aerial acrobatics some of these birds perform during courtship or territorial flights. Rollers resemble crows in size and build, and share the colourful appearance of kingfishers and bee-eaters, blues and pinkish or cinnamon browns predominating. The two inner front toes are connected, but not the outer one.

<span class="mw-page-title-main">European roller</span> Species of bird

The European roller is the only member of the roller family breeding in Europe. Its range extends into the Middle East, Central Asia and the Maghreb. It winters in southern Africa, primarily in dry wooded savanna and bushy plains. It occurs in a wide variety of habitats, but avoids treeless plains. It usually nests in tree holes.

<span class="mw-page-title-main">Pied kingfisher</span> Species of bird

The pied kingfisher is a species of water kingfisher widely distributed across Africa and Asia. Originally described by Carl Linnaeus in 1758, it has five recognised subspecies. Its black and white plumage and crest, as well as its habit of hovering over clear lakes and rivers before diving for fish, make it distinctive. Males have a double band across the breast, while females have a single broken breast band. They are usually found in pairs or small family groups. When perched, they often bob their head and flick up their tail.

<span class="mw-page-title-main">Red-throated wryneck</span> Species of bird from sub-Saharan Africa

The red-throated wryneck, also known as the rufous-necked wryneck or red-breasted wryneck, is a species of wryneck in the woodpecker family closely related to the Eurasian wryneck. Its three subspecies are resident in much of sub-Saharan Africa in open habitats with some trees. It is a slim, elongated bird about 19 cm (7.5 in) in length, with a small head, fine bill, long fan-shaped tail and cryptic plumage intricately patterned in greys and browns. The sexes look similar, although males are slightly larger. The diet of the adults and young is almost entirely ants at all stages of their life cycles. The call of the red-throated wryneck is a series of repeated harsh, shrill notes. When threatened, a bird will twist its neck and head in a snake-like manner while making a hissing sound, presumably to deter predators.

<span class="mw-page-title-main">Indian roller</span> Species of bird

The Indian roller is a bird of the family Coraciidae. It is 30–34 cm (12–13 in) long with a wingspan of 65–74 cm (26–29 in) and weighs 166–176 g (5.9–6.2 oz). The face and throat are pinkish, the head and back are brown, with blue on the rump and contrasting light and dark blue on the wings and tail. The bright blue markings on the wing are prominent in flight. The sexes are similar in appearance. Two subspecies are recognised.

<span class="mw-page-title-main">Abyssinian roller</span> Species of bird

The Abyssinian roller, or Senegal roller, is a member of the roller family of birds which breeds across tropical Africa in a belt south of the Sahara, known as the Sahel. It is resident in the southern part of its range, but northern breeding populations are short-distance migrants, moving further south after the wet season.

<span class="mw-page-title-main">Blue-bellied roller</span> Species of bird

The blue-bellied roller is a member of the roller family of birds which breeds across Africa in a narrow belt from Senegal to northeast Democratic Republic of the Congo. It is resident, apart from some local seasonal movements, in mature moist savannah dominated by Isoberlinia trees.

<i>Eurystomus</i> Genus of birds

Eurystomus is a genus of roller, one of the two genera in that family of birds. The name means ‘broad mouth’, from the Greek eurus and stoma.

<span class="mw-page-title-main">Oriental dollarbird</span> Species of bird

The Oriental dollarbird is a bird of the roller family, so named because of the distinctive pale blue or white, coin-shaped spots on its wings. It can be found from Australia to Korea, Japan and India.

<span class="mw-page-title-main">Eastern chanting goshawk</span> Species of bird

The eastern (pale) chanting goshawk, or Somali chanting goshawk, is a bird of prey of East Africa.

<span class="mw-page-title-main">Augur buzzard</span> Species of bird

The augur buzzard is a fairly large African bird of prey. This species is distinct in typical adult plumage for its blackish back, whitish underside and orange-red tail, while juvenile augur buzzards are generally rather brown in colour; however a dark morph is known, which causes the bird's entire body to become darker. This member of the Buteo genus is distributed in several parts of the central and southern Africa, normally being found from Ethiopia to southern Angola and central Namibia. It is resident and non-migratory throughout its range. This is a species of mountains, and adjacent savannah and grassland. This is a typical buteonine raptor, being a generalist predator which tends to prefer small mammals supplemented by reptiles and birds among various prey items.

<span class="mw-page-title-main">Purple roller</span> Species of bird

The purple roller, or rufous-crowned roller, is a medium-sized bird widespread in sub-Saharan Africa. Compared with other rollers its colours are rather dull and its voice harsh and grating.

<span class="mw-page-title-main">African barred owlet</span> Species of owl

The African barred owlet is a species of small owl in the family Strigidae found in much of southern, central and eastern Africa. The taxon may be four species rather than a single species.

<span class="mw-page-title-main">Racket-tailed roller</span> Species of bird

The racket-tailed roller is a species of bird in the family Coraciidae. It is found in southern Africa from Angola, south-eastern Democratic Republic of Congo and southern Tanzania to northern Botswana, Zimbabwe, Malawi and Mozambique.

<span class="mw-page-title-main">Purple-winged roller</span> Species of bird

The purple-winged roller is a species of bird in the family Coraciidae. It is endemic to the Sulawesi subregion in Indonesia and can be found on the islands of Sulawesi, Bangka, Lembeh, Manterawu, Muna and Butung.

<span class="mw-page-title-main">Brown-hooded kingfisher</span> Species of bird

The brown-hooded kingfisher is a species of bird in the subfamily Halcyoninae, the tree kingfishers. It has a brown head and blackish and turquoise wings. It is found in Sub-Saharan Africa, living in woodland, scrubland, forest edges, and also suburban areas. The International Union for Conservation of Nature (IUCN) has assessed it as being of least concern.

<span class="mw-page-title-main">Striped kingfisher</span> Species of bird

The striped kingfisher is a species of bird in the tree kingfisher subfamily. It was first described by Edward, Lord Stanley, in Salt's Voyage to Abyssinia in 1814 as "Chelicut kingfisher" Alaudo Chelicuti.

<span class="mw-page-title-main">Abyssinian wheatear</span> Species of bird

The Abyssinian wheatear, or Abyssinian black wheatear, is a species of bird in the family Muscicapidae, the Old World flycatchers and chats. It is found from Ethiopia to southern Kenya and north-eastern Tanzania.

<span class="mw-page-title-main">Indochinese roller</span> Species of bird

The Indochinese roller or Burmese roller, is a member of the roller bird family. It occurs widely from Nepal, eastern India to Myanmar and Southeast Asia. It is listed as Least Concern on the IUCN Red List.

<span class="mw-page-title-main">Broad-billed roller</span> Species of bird

The broad-billed roller is a member of the roller family of birds which breeds across tropical Africa and Madagascar in all but the driest regions. It is a wet season breeder, which migrates from the northern and southern areas of its range towards the moister equatorial belt in the dry season.

References

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