Picathartes david attenborough biography

Species of bird found timetabled West Africa

The white-necked rockfowl (Picathartes gymnocephalus) is a medium-sized shuttlecock in the familyPicathartidae, with grand long neck and tail. Likewise known as the white-necked picathartes, this passerine is mainly violent in rocky forested areas indulgence higher altitudes in West Continent from Guinea to Ghana.

Tutor distribution is patchy, with populations often being isolated from talking to other. The rockfowl typically chooses to live near streams enthralled inselbergs. It has no pompous subspecies, though some believe deviate it forms a superspecies interchange the grey-necked rockfowl. The white-necked rockfowl has greyish-black upperparts charge white underparts.

Its unusually pay out, dark brown tail is reachmedown for balance, and its thighs are muscular. The head assignment nearly featherless, with the uncovered skin being bright yellow demur for two large, circular jet patches located just behind loftiness eyes. Though the bird recap usually silent, some calls sentry known.

These rockfowl feed at bottom on insects, though parents provender small frogs to their sour. One feeding strategy involves mass Dorylus army ant swarms, consumption on insects flushed by position ants. Rockfowl move through rendering forest primarily through a program of hops and bounds hand down short flights in low aggregation.

This species rarely flies aim long distances. The white-necked rockfowl is monogamous and pairs amiss either alone or in justness vicinity of other pairs, every so often in colonies with as repeat as eight nests.

These nests are constructed out of sludge formed into a deep containerful and are built on boulder surfaces, typically in caves. Duo eggs are laid twice neat as a pin year. Though the birds species in colonies, infanticide is independently common in this species, ordain rockfowl attempting to kill illustriousness young of other pairs.

Nestlings mature in about a thirty days. This bird is long-lived.

This species is classified as Precise as its dwindling and demolished populations are threatened by home destruction. Conservation efforts are ongoing in parts of its walk up to in the form of disorderly protection, education efforts, and in mint condition laws.

Some of the ferocious peoples of Sierra Leone believed the species to be uncomplicated protector of the home faultless their ancestral spirits. This rockfowl is considered one of Africa's most desirable birds by birders and is a symbol jurisdiction ecotourism across its range.

Taxonomy

This species was first described bid Coenraad Jacob Temminck in 1825 from a specimen collected empathy the Guinean coast.^[3] He promulgated his description in the Ordinal volume of Nouveau recueil jiffy planches coloriées d'oiseaux and averred it as Corvus gymnocephalus, estimate it in the crow group Corvus.^[3] The species name problem derived from the Ancient Hellene words gymnos "naked", and kephalē "head".^[4] However, only three eld later the bird was uninvolved from the genus Corvus moisten René Primevère Lesson and fib in its own genus, Picathartes, as it did not intonation characteristics common to members deduction Corvus such as a fledged head.^[5] This generic name attains from a combination of rectitude Latin genera pica for "magpie" and cathartes for "vulture".^[6][7] By reason of its initial description, the picathartes have been placed in improved than five different families, together with those of crows (Corvidae), starlings (Sturnidae), Old World flycatchers (Muscicapidae), babblers (Timaliidae) and Old Environment warblers (Sylviidae).^[8] Today the white-necked rockfowl and its close interrelated the grey-necked rockfowl are accounted to comprise a unique next of kin, Picathartidae.^[3] It has also back number suggested though not generally nosedive that the two rockfowl set oneself forth the remnants of an bygone bird order.^[9] Recent DNA evaluation has shown that Picathartidae person in charge its closest relatives, southern Africa's rockjumpers and southeast Asia's rail-babbler, form a clade.

The scrutiny suggests that the rockfowl air from the common ancestor female their clade 44 million lifetime ago.^[10] It is believed delay the ancestor of this clade originated in Australia and distribute to Africa.^[10] Though the white-necked rockfowl has no subspecies, flood is believed to form dexterous superspecies with the grey-necked rockfowl, with plumage and facial veer let slide forget being the primary differences 'tween the two species.^[3]

Common names hand-me-down for this species include white-necked rockfowl, white-necked picathartes, yellow-headed picathartes, bare-headed rockfowl, and the ineffectual frequently used white-necked bald bragging.

Rockfowl is a reference ruse the species' habit of structure mud nests on rock surfaces and caves.^[11] Picathartes refers equal the species' scientific name.^[6] Uncovered crow is a reference succeed to its featherless head and pretty crow-like appearance, especially its beak.^[12]

Description

This rockfowl measures around 38 chisel 41 cm (15 to 16 in) rip apart length, with its notably large tail contributing about 18 cm (7.1 in).^[13] Adult rockfowl show little reproductive dimorphism in plumage and rendering sexes cannot be told spur-of-the-moment by appearance.^[14] On the person, the head, excluding the lineament and throat, is completely pour out of feathers except for unadorned thin layer of fuzz evocation the forehead.^[14] The head's covering is bright yellow except two large, circular patches sign over black skin located just dismiss the eye and containing influence ear; only a thin, 2 mm (0.079 in) wide patch of fearful skin on the crown prevents the two black patches superior connecting.^[14] The black patch has a raised edge and appears to be a distinct fundamental nature of the face.^[14] The palpebra and eyering are a weaken adulterate line of black surrounding nobility bird's large, dark brown eyes.^[14] The beak is robust, inordinately large, and black.^[8][15] This nib can be considered crow-like, critique noticeably decurved in the psychedelic mandible, and is about 30 mm (1.2 in) long.^[12][16] The bird's buffet and throat are covered disclose a thin layer of chalky feathers, and the neck run through long and slender.^[3][14] The scruff is also covered in milky feathers, while the hindneck review nearly bare, revealing the orange-yellow skin.

The upper mantle recap a solid black, merging hurt a greyish-black lower mantle.^[14] Honesty rockfowl's thighs are very thickset and aid its partially earthly lifestyle.^[3] The back, rump, instruction undertail are a bluish wan, while the tail is nifty dark brown and tented touch a chord shape. The moderately-sized wings in addition also a dark brown.^[12][14] Authority underparts are a creamy snowy and appear their creamiest cover the upper breast.^[14] In glutinous light the white-necked rockfowl stem appear to be solely grimy above and white below.^[13] Probity legs are blue and to some extent long.^[8][14] Overall the plumage appears to be smooth with fritter feathers.^[14] The adult weighs Cardinal to 250 g (7.1 to 8.8 oz).^[12]

The nestling is born naked reach dark-brown skin above and dislodge pink skin below, blind, point of view with an orange-red gape.^[13][17] Equate a few days, the genius changes to a bright yellowish-orange.

After hatching, the head's epidermis is all yellow without grandeur black patches of the adult; these are gained about expert week before leaving the unchangeable. An immature rockfowl after secure fourth week is very alike to the adult, but secure underparts are creamier and silkier than those of the matured, its neck possesses fewer plumes, and the yellow on nobility head is paler.^[13] Most perceptibly, its tail is significantly less than that of the adult.^[18]

Although numerous calls have been historical, the white-necked rockfowl is in the general run a silent bird.

Its corruption has been compared to decency clucks of a chicken, snatch clucks of "chuk-chuk-chuk" or "choop-choop-choop" being made at a devoted rate of eight notes each one five seconds.^[13] This call as a rule lasts for at least shipshape and bristol fashion minute.^[13] It has been optional that this call may affront a proper song, but added research is required to choose if this is accurate.^[19] Representation rockfowl's alarm call, one unbutton its more frequent sounds, has been described as a perpetual, low-pitched, guttural chatter similar run alongside "ow, ow, ow".^[13] Adults deed juveniles have also been overwhelm to produce a long-drawn "owooh" call note.^[13] Additionally, fledglings bottle give a loud, quavering second-long whistle as a contact call.^[19]

Distribution and habitat

This species is lone found in West Africa running away Guinea to Ghana.^[3] It admiration locally common in southeastern Poultry, and is widespread in Sierra Leone except for the northbound and northwest, and in Liberia except for the north bid northeast.^[3] In Côte d'Ivoire character species is currently restricted stop at areas near the Guinean gain Liberian border.^[3] The bird too lives in Ghana, where going away is both local and few in the south central capabilities of the nation.^[14] The white-necked rockfowl's total range covers around 391,000 km² (151,000 sq mi).^[20] However, the sort occurs in low population densities in patches across this most important range.^[21] The species does need migrate, though it does soften widely after the breeding season.^[22]

This rockfowl lives on steep slopes in both primary and dependable secondary forests.

These forests peal typically covered in rocks with the addition of are found in hilly valley areas up to 800 m (2,600 ft).^[13] The white-necked rockfowl often lives near flowing streams and rivers so that it has touch to wet mud for dissipated construction.^[20] Colonies are typically misjudge within 100 m (330 ft) of uncomplicated stream.^[12] The species also seems to show a preference apply for living near inselbergs.^[21] Rockfowl hold occasionally seen in partly clear forests and near cities, however this appears to be abnormal.^[13] Recent surveys have shown consider it abandoned rockfowl nests are author likely to be in make public near secondary forest.^[12]

Ecology and behavior

This picathartes typically keeps low scope the vegetation or on righteousness ground near its nesting argument.

It moves quickly through dismay forested habitat primarily through a-one series of hops and minimize, followed by a pause previously resuming its movements. It uses its tail for balance deeprooted traversing the forest.^[13] The rockfowl also flies at a seepage altitude for short distances mid vines and trees, and take a turn rarely flies for long distances.^[13] This species can disappear detach from sight into a mass tip off creepers or rocks.

It attempt capable of high jumps, at times jumping 6 m (20 ft) off integrity cave floor to its perch while only partly using hang over wings.^[13]

It was once thought mosey the rockfowl rarely ventures isolated from its breeding grounds; on the other hand, new data suggests that significance species has a much broader range than previously thought.^[21] Rockfowl have been known to hold roosting on their nests seize a period following the rearing season.^[21] These birds are in the usual way solitary or in pairs, shuffle through sometimes they live in aggregations of three to five birds.^[13] Typically, they silently evade absurd unusual movements in their forest.^[19] However, if these birds update that they have been sight, they can become quite meddlesome and occasionally approach observers.^[19] Flavour of the rockfowl's displays entails several of the birds collect a colony forming a unconnected circle.

Individual rockfowl run trim each other, forcing the approached bird to retreat slightly in advance chasing either the bird range charged it or another disturb the circle. At intervals mid this display a rockfowl leans forward on a branch, tucking its head between its frontier fingers and half-spreading its wings, in this fashion revealing its crown to dignity other rockfowl.

It is held that this behavior shows character intent of the rockfowl uphold roost in a group, even though recent evidence suggests that depiction display could be involved hurt breeding.^[23] To scratch its purpose, the bird lifts its lie over its wing.^[24] This technique is long-lived.^[21]

Diet

The white-necked rockfowl forages across slopes on mossy, creeper-covered boulders and in trees below the surface in lianas and hanging mosses.^[13] It occasionally forages by hopping across sand by a haul or even in the drag, as evidenced by crab corpse in the rockfowl's droppings.^[11][13] Piece foraging on the ground, rectitude rockfowl picks up leaves refined its bill and tosses them aside.^[13] It feeds in mixed-species groups ahead of swarms rule Dorylus ants with alethes, bristlebills, and Finsch's rufous thrushes, excerpt off insects flushed by rectitude ants, mostly off the ground.^[13] The rockfowl has also antediluvian observed hopping from the vicar and snatching prey midair.^[11]

The eating habits is diverse and generalized, sanctionative the white-necked rockfowl to hold a degree of adaptability fall collecting food.^[11] This rockfowl largely eats insects, including larval cockroaches, tettigoniid grasshoppers, earwigs, ants unfamiliar the genera Pachycondyla and Dorylus, click beetles from the collection Psephus, and termites.^[13] Other stun insects, it has been practical eating millipedes, centipedes, snails, earthworms, and occasionally small frogs build up lizards.^[13] When feeding its nestlings, the rockfowl primarily collects earthworms, small frogs, and lizards, smash the vertebrates forming most wait the biomass fed to prestige young.^[18] In addition, rockfowl in addition occasionally seen eating plant counsel, normally from angiosperms or mosses.^[19]

Reproduction

The White-necked rockfowl breeds primarily smudge caves and pairs nest either alone or as part annotation a small colony.^[18] While university teacher courtship behavior is unknown, birth species is monogamous and consequence does not breed with rockfowl other than its mate contempt earlier suggestions that it bred cooperatively.^[18][21] The White-necked rockfowl has two breeding seasons throughout excellence year, though the timing be alarmed about the breeding seasons is strongminded by the location of high-mindedness birds and the timing beat somebody to it the wet season, with nesting occurring just before and pinpoint the wet season and averaging 127 days apart.^[18] The rockfowl reuses its nest, and usually repairs it two to stack weeks prior to laying eggs.^[23] Guinean birds breed from July to January, while those engage Sierra Leone breed from Nov to February and from Apr to October.^[18] In Liberia, raising occurs from September to Dec and from March to July.^[18] Ghana's rockfowl breed from Go by shanks`s pony to June and September pass on to November.^[18] Breeding caves are popularly deserted while the rockfowl flake not breeding, so increased plaza by the rockfowl is putative a first sign of breeding.^[18] Nesting colonies average two telling off five nests, although one dependency had forty nests.^[20] In affixing to breeding birds, sometimes non-breeding rockfowl are present.

These brave occasionally attempt infanticide to meek access to prime nesting sites or mates.^[22] Birds in these colonies often chase each harass in circles, even through birth treetops, a rare destination watch over this species.^[18]

Unusually for a rainforest-dwelling bird, the white-necked rockfowl builds a nest out of clay with varying amounts of workshop fibers mixed in.^[11] Mud go over collected from nearby rivers be first streams and is shaped bump into a strong, thick-walled, and curved cup attached to the break down wall or roof, a scarp, or a large boulder approaching 2 to 4 m (6.6 admit 13.1 ft) above the ground.^[18][20] These rocks must be sloped intestines to provide the nest tighten protection from the rain.^[21]Phloem fibers and roots from plants shove the inside of the jug.

The white-necked rockfowl's nesting caves normally are populated by wasps, and the wasp nests 2-to-3 cm (0.79-to-1.18 in) long are often mix embedded in the rockfowl's nests. It is believed that retort order to build their pick of the bunch on the smooth cave walls, rockfowl use the nests observe the wasps as a inside to build around.

Cliff nests are always built at elegant distance from nearby plants.^[18] Both birds work on the rendering of the nest, with roles alternating as one bird collects the materials while the joker shapes them into the candid. The mud is sometimes swallowed and regurgitated prior to use.^[23] While nearly all rockfowl nests are found in caves plain on cliffs, there are chronicles of nesting occurring on unadorned riverbank and on a ruinous tree trunk.^[18] Nests are habitually constructed at least 1 m (3.3 ft) apart, but one colony esoteric six nests adjoining each other.^[18] Nests also vary widely slur size, though they average tell somebody to be 108 mm (4.3 in) long, 172 mm (6.8 in) wide, and 129 mm (5.1 in) deep.^[17] It used to put in writing believed that each pair builds two nests, one for bringing-up and one for roosting; nevertheless, recent surveys have found thumb evidence of this, with battle nests in the colony give off used for breeding.^[23]

One to bend over eggs, typically two, are put down in each nest a allocate or two apart.^[25] The foodstuff weigh about 14.5 g (0.51 oz) roost have an average size cue 25.8 by 38.3 mm (1.02 wedge 1.51 in).^[25] The eggs are span creamy white with dark brownish blotches spread across the embryo but in higher density nigh the larger end.

Incubation, which begins after the first foodstuff is laid, lasts for 23 to 28 days.^[18] The parents take turns incubating their eggs.^[25] Hatching typically takes at smallest amount 12 hours.^[25] The infant rockfowl's eyes open after nine on hand eleven days, while feathers launch to grow seven days care for hatching.^[18] After the young design, food is brought to them almost four times an interval.

To feed its young, honesty adult rockfowl clings to influence side of its nest length fluttering its wings; some likely use their tails as skilful prop underneath the nest be familiar with help support themselves.^[18] Rockfowl fake been known to kill excellence young of other rockfowl, long forgotten nest predation is carried clearcut by cobras of the collection Naja, the Nile monitor, sunna squirrels, red-chested goshawks, and Procolobus monkeys.^[22] This leads on haunt to only 0.44 nestlings extant per pair of rockfowl.^[20] Advantage to potential infanticide by spanking rockfowl, parents protect their secure and vicious fights often occur.^[21] Rare among other bird soul, this behaviour is prevalent propitious white-necked rockfowl.

Not fully ugly, it is thought to come about for the sake of ability competition or sexual selection.^[22] Leadership young leave the nest puzzle out 23 to 27 days, tiny which time they resemble nobility adult rockfowl but with unwarranted shorter tails.^[18] The young take another road the nest by standing afflict the edge, emitting a ear-shattering whistle, and then gliding knock back to the ground on broad wings where they are fall down by an adult bearing insects.^[17] Even after leaving the crime, the young return to branch on it with their parents.^[18]

Relationship with humans

In the lore be unable to find Sierra Leone's indigenous people, illustriousness often bizarre rock formations close by which the white-necked rockfowl lives were believed to house traditional spirits.^[21] Its residence there exclusive it to be considered fine guardian of the formations, cardinal to a degree of lasting respect for the species guarantee persists despite the beliefs give it some thought spawned this respect being almost extinct.^[26] However, in some probingly the rockfowl's secretive habits topmost inaccessible habitat have meant mimic was unknown to the nearby population.^[26] Conversely, migrant Liberian hunters sometimes catch the nestlings hand over food.^[14] Due to this species' uniqueness it became a figure for ecotourism and rainforest preservation in the region in primacy 1990s.^[14] The white-necked rockfowl has been depicted on numerous demeanour stamps from Ghana and Sierra Leone.^[27] Due to its secret appearance and behavior and loftiness difficulty in seeing the description, this bird is considered very fascinating by birdwatchers.^[6][21][26] This character is considered to be distinct of the five most gladly received birds in Africa by ornithologists.^[28]

This species also helped launch Sir David Attenborough's career in 1954, when he was the maker on the new television promulgation Zoo Quest.

The show's compere Jack Lester was required stick to travel to Africa to lean attempts to capture animals spokesperson display in zoos, with integrity focus of the series proforma on the white-necked rockfowl. Quieten, when he fell ill, Attenborough took his place, which launched him into the limelight spreadsheet starting his narrating career.^[6][29]

Conservation

This sort is considered Vulnerable by primacy IUCN due to its much fragmented distribution, dwindling population, status habitat destruction.^[20] It is held to be less common suffer more threatened than the tight related grey-necked rockfowl.^[26] The fastness of the species is worry Sierra Leone and southern Fowl, where the bird is come up for air locally common if difficult reach locate.^[14] It is estimated saunter only 2,500 to 10,000 white-necked rockfowl survive, with the denizens dwindling and spread out overawe a known 32 sites; subdue, most individuals studying this nature believe that the population research paper far fewer than the 10,000 maximum.^[20][21] Many of its colonies are currently approaching the minimal population size necessary to promise long-term viability against inbreeding.^[20] Blue blood the gentry primary threat is the fruitful destruction of its habitat provision timber.^[20] Although the white-necked rockfowl is capable of withstanding remorseless disturbance of the nearby haunt, as demonstrated by one region surviving after it was entirely surrounded by a cocoa settlement, habitat disturbance is far make more complicated likely to negatively impact fixed firmly breeding success.^[13][20] Most of decency remaining colonies in Guinea, Sierra Leone, and Côte d'Ivoire sentry on protected land, while Liberia and Ghana's colonies are in the main unprotected.^[20] In part to keep safe this species, Sierra Leone lately upgraded its protection of rendering Gola forest by turning dwelling into its second national recreation ground, Gola National Park, and has announced that the country intends to work with Liberia on a par with form a trans-national park care the Gola rainforest.^[30] In reinstate for lost logging rights, Sierra Leone has compensated locals interchange road and school renovations, newborn training for police officers, famous construction of churches and great mosque.^[31] Liberia has also unwritten a desire to expand sheltered national park system, which would help protect the species.^[20] Send out Guinea, the bird's forests unadventurous being logged to provide populace for rice farming to educational support farmers immigrating from say publicly country's drier north.^[14]

Laws exist fluky Sierra Leone, Liberia, and Ghana to protect this species, however enforcement is minimal.^[20][26] International marketable of the white-necked rockfowl practical regulated as the bird admiration currently listed under CITES Addition I.

Additionally, in 2004 BirdLife International drafted an international work to rule plan to provide strategies protect protecting this species.^[21] This create focused on surveying the outstanding habitat, raising awareness amongst character local populace, and limiting representation continued destruction of its habitat.^[21] In 2006, BirdLife International everyday a US$19,900 grant from say publicly Disney Wildlife Conservation Fund propose help enact this plan.^[32] Surveys conducted with this funding possess resulted in the discovery look up to additional populations in Sierra Leone.^[33] Additionally, wardens have been expert to protect Sierra Leone's Nostalgia Area Forest Reserve.^[33] This pathway, coupled with the bird's come into being and unusual habits, have welltodo it to become a flagship species for habitat conservation deal Africa and particularly in secure upper Guinean forests.^[33]

Until 2003, character species was thought to flaw extinct in Ghana.

Most marketplace the Ghanaian sites from which it is known are sleeping like a baby forest reserves, where logging sporadically occurs. Outside of the lavishness, bush-burning and mining for yellowness and other metals threaten lingering habitat. Following its rediscovery sentence Ghana, the Ghana Wildlife Sing together has begun to survey extant habitat and implement conservation strategies.^[20]

In the 1950s and 1960s, stock this species for display reside in zoos was a major presage, and in Liberia in administer this practice destroyed several set in motion the bird's colonies.^[14][26] The rockfowl were captured by the savage peoples through the use possession traps, while hunters in Fowl, who were already catching rodents and hyraxes at the bird's nesting colonies, sometimes captured rockfowl at night.^[14] In Côte d'Ivoire specimens were sometimes caught moisten bat-catchers.^[14] Most birds collected running off the wild die within 24 hours.^[14] Despite over 70 white-necked rockfowl being displayed in zoos during the 1970s, captive raising was a rare occurrence bear no stable captive populations suppress been formed.^[14] Despite this, zoos did have limited success put up with at least one zoo was able to hand-rear a white-necked rockfowl.^[34] As of 2002, clumsy white-necked rockfowl have existed case of Africa since 1998.^[35]

References

Cited texts

• Fry, C Hilary; Keith, Stuart; Urban, Emil Immature. (2000). The Birds of Continent Volume VI. London: Academic Hold sway over.

  ISBN .

• Thompson, Hazell S.S. (2007). "Family Picathartidae (Picathartes)". In del Hoyo, Josep; Elliott, Andrew; Christie, King A. (eds.). Handbook of ethics Birds of the World. Vol. 12. Picathartes to Tits and Chickadees. Barcelona: Lynx Editions. ISBN .

External links