Long-tailed ground roller

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Long-tailed ground roller
Overall with blue on its wing, looks right with its long tail pointed straight back while standing in reddish-brown sand in a thicket.
Adult in Mangily, Madagascar
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Coraciiformes
Family: Brachypteraciidae
Genus: Uratelornis
Rothschild, 1895
Species:
U. chimaera
Binomial name
Uratelornis chimaera
A map of southern Madagascar highlighting the distribution of the long-tailed ground roller along the southwestern shore north of Toliara.
Distribution (orange) in southern Madagascar

The long-tailed ground roller (Uratelornis chimaera) is a

breeding season
, though multiple courtship calls are made.

These ground rollers feed primarily on

scrubland
.

This bird is classified as

native peoples of Madagascar
.

Taxonomy

British banker and

cuckoo roller, and rollers were all placed in a single family, Coraciidae, in which each of the three groups formed a subfamily.[4][8] In 1971, Joel Cracraft proposed a separate family for the ground rollers based on significant differences in behavior, plumage, and post-cranial anatomy between the groups.[9] This position is supported by DNA evidence.[8] It has been suggested, but not widely accepted, that ground rollers are closely related to the puffbirds and jacamars.[4][10] It has been speculated that the ancestor of the long-tailed ground roller was an arboreal roller that crossed over from Africa to Madagascar and developed a terrestrial lifestyle before moving from the rainforests into the long-tailed ground roller's arid scrubland.[4] No fossils have been found for this genus, and genetic analysis suggests that this bird's closest relative is the scaly ground roller.[8] The long-tailed ground roller has no subspecies.[11]

Description

Adult cocking its head and showing its white chin lined with brown stripes in a sandy thicket.
The long-tailed ground roller is largely terrestrial.

The long-tailed ground roller's silhouette is highly distinctive due to its long tail and plump silhouette.

zygodactylous, with the first and fourth toes turned outwards and the middle two toes turned inwards.[13] The female resembles the male, but is smaller and has a narrower chestband and a shorter tail.[11][14] Also, the female loses her tail while nesting.[13] These differences make the long-tailed ground roller the only ground roller to definitively display sexual dimorphism.[4] Juveniles of both sexes resemble the adult female, but have duller plumage, particularly in the black bands on the chest, neck, and eyes.[12]

Although it is generally a silent species, during the breeding season the vocalizations of the long-tailed ground roller include a "hooting" sound, a "popping" tu-tuc, and a soft boo sound.[12][14][15] The low-pitched "hooting" is given by males from a perch 2 to 6 meters (6.6 to 19.7 ft) above the ground at dusk or at night. The sound carries for a distance of at least 200 meters (660 ft) and may either attract a mate or defend a territory. The bird pumps its tail while giving this call.[14] One territorial call is a series of soft boo notes, typically coming in sets of six to ten and descending in volume near the end.[11] Another call, given by both sexes, is a series of chuckling tu-tuc sounds lasting between 10 and 40 seconds that occasionally ends in a loud snapping sound produced by the wings.[11][14] This call is given when birds are close to each other either on the ground or on low perches, and it does not carry over long distances. The use of wing-snapping to produce a sound is a rare phenomenon in birds, and in the order Coraciiformes only one other family, the todies, is known to do it.[14] Low gu notes are given by mates as they come in contact with each other.[11]

Distribution and habitat

Spiny forest at Ifaty, featuring an Adansonia
(baobab) species and other vegetation

Endemic to the island nation of Madagascar, the long-tailed ground roller inhabits a narrow strip of suitable habitat by the coast in the southwestern part of the island.[16] This strip is bordered by the Mangoky River in the north, the Fiherenana River in the south, and lowland hills in the east.[11] It totals about 10,500 square kilometers (4,100 sq mi) in area; however, the species is extremely uncommon within its range and occurs at densities of about 0.8 to 10 per square kilometer (2.1 to 25 per square mile).[1] This area ranges in elevation from sea level to 100 meters (330 ft).[11] The long-tailed ground roller does not migrate, though it may disperse across a larger area outside the breeding season.[15]

This species' prime habitat is spiny forest, a mix of sub-arid

spiny forests belong to the cactus-like family Didiereaceae (especially Didierea madagascariensis) and more tree-like family Euphorbiaceae (especially Euphorbia stenoclada).[17] Baobab trees are also prevalent.[11] It was formerly believed that the long-tailed ground roller preferred an undisturbed forest habitat, while tolerating small amounts of disturbance.[16] Later studies have concluded that it actually prefers degraded habitat.[1] Despite this, shade is necessary, and the species is not found in deforested habitat or on the shadeless dunes prevalent in its range.[1][11]

Ecology and behavior

The long-tailed ground roller is a shy and elusive bird and, if seen by a human observer, it either freezes or runs away. As its short wings suggest, the species rarely flies, but it is a powerful runner.[17] While largely terrestrial, it roosts in low trees and bushes, and sings from low perches.[1] Long-tailed ground rollers are solitary outside the breeding season. Although diurnal, it does occasionally forage at night unlike most other ground rollers.[18] When calling, this ground roller bobs its head and raises its tail.[19] The long-tailed ground roller also raises its tail when it is excited.[19]

Diet

This species forages almost exclusively from the ground, where it alternates between remaining still and watching attentively and actively searching for it by rummaging through deep leaf litter.[16][19] It eats a wide range of invertebrates, including ants, beetles, butterflies, caterpillars, cockroaches, grasshoppers, woodlice, and worms, and occasionally small vertebrates. Despite the long-tailed ground roller's poor flying abilities, it has been seen catching butterflies in midair.[11]

Reproduction

A small hole descends into the red sandy earth at an angle.
Entrance to a nesting burrow

The breeding season coincides with the

feeding the female.[20]

Male and female long-tailed ground rollers use their bills and feet to excavate a burrow in consolidated, flat sand and construct their nest at the end of it.[18][21][22] The burrow, always constructed away from grassy vegetation, is downward-sloping and is between 0.8 and 1.2 meters (2.6 and 3.9 ft) long with a diameter of 8 centimeters (3.1 in). The end of the burrow widens into a 20-centimeter (7.9 in) wide chamber with a shallow depression covered in dry leaves and earthy pellets.[20] When digging its nest, the long-tailed ground roller occasionally walks underneath a low branch, tilts its head upwards, and, while remaining motionless, releases a rising crescendo of its tu-tuc calls. At the height of the crescendo the bird breaks off its call and flies upwards onto the branch while producing a "ripping and crackling sound" with its wingbeats.[14] From the perch the bird releases a stream of boo notes. This display is thought to be part of a courtship ritual.[14] Each pair digs one to six nesting burrows during the breeding season; the extra burrows are known as speculative burrows.[18]

Between October and January, and peaking in November, the species normally lays two smooth, white eggs, though sometimes it lays three or four.

incubation period and fledging time of this ground roller is unknown.[20] After the young fledge, they live in a family group of four to five birds until approximately February, at which point the family disperses.[18]

Conservation

Classified as

egg-collecting. In addition to humans, dogs hunt this species, and the introduced black rat is a nest predator.[23] This ground roller is capable of tolerating some habitat disturbance, but requires a suitable amount of shade and leaf litter to continue living in the area.[16] Although it was fairly common at the beginning of the twentieth century, its population went into decline and it was considered rare by the 1960s.[25] As of 2012, the estimated population of the long-tailed ground roller is between 9,500 and 32,700 birds and declining.[1]

Relationship with humans

As the long-tailed ground roller is remarkably silent and difficult to see during the non-breeding season, the

birdwatchers to be one of the world's most elusive birds.[28]

References

  1. ^
    doi:10.2305/IUCN.UK.2016-3.RLTS.T22682969A92970628.en
    . Retrieved 16 November 2021.
  2. Rothschild, Walter (Dec 1895). "A New Species and Genus of Rollers"
    . Novitates Zoologicae. 2 (4). London: Hazel Watson & Viney Ltd.: 479.
  3. ^ "History of the Collections". History. The Natural History Museum. 2013. Retrieved 2013-04-24.
  4. ^ a b c d e f g Langrand 2001, p. 378
  5. ^ Jobling 2010, p. 396
  6. ^ Jobling 2010, p. 58
  7. ISBN 978-0-533-16080-8
    .
  8. ^
    S2CID 85861288
    .
  9. JSTOR 4083834
    .
  10. JSTOR 4086285
    .
  11. ^ a b c d e f g h i j k l m n o p q r s t u Langrand 2001, p. 388
  12. ^
    ISBN 1-86872-956-7
    .
  13. ^ a b c Langrand 2001, p. 379
  14. ^
    S2CID 86233404
    .
  15. ^ a b c Langrand 2001, p. 383
  16. ^ a b c d e Langrand 2001, p. 380
  17. ^ a b Langrand 2001, pp. 380, 388
  18. ^
    doi:10.1017/S095927090600058X
    .
  19. ^ a b c Langrand 2001, p. 381
  20. ^ a b c d e Langrand 2001, p. 382
  21. ^ Langrand 2001, pp. 382, 388
  22. ^ a b c Jenkins 1987, p. 246
  23. ^ a b Langrand 2001, p. 384
  24. doi:10.1046/j.1365-3008.2000.00134.x
    .
  25. ^ Jenkins 1987, p. 245
  26. ^ Scharning, Kjell. "Long-tailed Ground Roller Stamps". Kjell Scharning. Retrieved 2011-10-29.
  27. ISBN 978-3-8171-1636-2
    .
  28. ^ Keith, Stuart (July–August 1974). "Birding planet Earth — a world overview". Birding. 6. American Birding Association: 203–216.

Cited texts

External links

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