Walden's hornbill

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Walden's hornbill
Writhed-billed Hornbill (Bentley).jpg
male
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Bucerotiformes
Family: Bucerotidae
Genus: Rhabdotorrhinus
Species:
R. waldeni
Binomial name
Rhabdotorrhinus waldeni
(Sharpe, 1877)
Synonyms

Aceros leucocephalus waldeni
Aceros waldeni

Walden's hornbill (Rhabdotorrhinus waldeni) locally called dulungan, also known as the Visayan wrinkled hornbill, rufous-headed hornbill or writhe-billed hornbill, is a critically endangered species of hornbill living in the rainforests on the islands of Negros and Panay in the Philippines. It is closely related to the writhed hornbill, but can be recognized by the yellow throat and ocular skin in the male, and the blue throat and ocular skin in the female (both throat and ocular skin are deep orange or red in both sexes of the writhed hornbill). Its binomial name commemorates the Scottish ornithologist Viscount Walden.

Contents

It is considered one of the Western Visayas Big 5 which includes the Negros bleeding-heart pigeon, Visayan spotted deer, Visayan hornbill and the Visayan warty pig. [2]

Description

EBird describes the bird as "A large rare bird of lowland and foothill forest on Panay and Negros, although almost extinct on the latter. Mostly black with a cream-colored tail with black terminal band, an orange casque , and a wrinkled lower bill. Male has a rufous head, a yellow pouch, and yellow around the eye. Female has a black neck and head, a smaller bill and casque , and blue and yellow around the eye and on the chin. The only other hornbill in range is the Visayan hornbill but the Writhe-billed is larger, with a pale bill. Voice includes a three-noted throaty chuckle.." [3]

They exhibit sexual dimorphism with the males having a rufous head and yellow facial skin while the females having a black head and blue facial skin and a smaller bill.

Habitat and behaviour

Male carrying a small fruit. As most other hornbills, this species is primarily a frugivore. A waldeni flying.jpg
Male carrying a small fruit. As most other hornbills, this species is primarily a frugivore.

It inhabits closed-canopy forests, also frequenting logged areas and occasionally isolated trees in clearings at an altitudinal range of 400 to 1,200 m Panay and 350 to 950 m in Negros. It prefers areas abundant fruit-bearing trees for feeding and large trees for nesting. They are known to live in small and noisy flocks. The Walden's hornbills are cavity nesters and use natural or carved-out hollows in tree trunks for its nest. As other hornbills, they reproduce very slowly. As lack of appropriate nesting sites is a problem, nest boxes are being attached to tree trunks in certain reserves.

It is omnivorous, taking some animal matter to its nests and feeding in the canopy on figs and other fruits. It may make local nomadic movements in response to food availability. It nests in large trees. [4]

Conservation status

This is a critically endangered species, one of the three critically endangered hornbills including the Sulu hornbill and Helmeted hornbill. It is presumed extinct on Guimaras and now survives only on Negros and Panay The total population has been estimated at less than 160, though recent work from the Central Panay Mountain Range suggests 600-700 pairs may remain there. No recent figures are available for Negros, where it may be functionally extinct. [5] The IUCN Red List estimates the population to be 1,000 to 2,499 mature individuals with the population continuing to decline.

Walden's hornbill reproduce very slowly and thus are unable to survive high hunting pressures coupled with heavy logging of the rainforests. By 2007, Negros and Panay had a 3% and 6% remaining forest cover with most of this being higher elevation forest where this bird does not thrive in. Despite already paltry forest cover, deforestation still continues thanks to both legal and illegal logging, conversion into farmland, mining and road development. As for the case of the Northwest Panay Peninsula Natural Park, a road was built splitting it from the Central Panay Mountain Range and has severely affected the population in the former as these roads allow for easier access by hunters and loggers.

Another huge threat is hunting and capture for the illegal wildlife trade. According to the Philippine Initiative for Environmental Conservation (Philincon), up to 50% of all nests in Central Panay Mountain Range were affected by poachers who would either climb up or cut down the nesting trees to poach the nestlings and the mother. [6]

Due to this high poaching rate, Philincon has devised a nest guarding program where they pay locals US$20 a month to guard hornbill nests and offer an incentive of US$11 for each successful fledge. This program has been effective cutting down the poaching rate to just 5%. Philincon now guards more than 1,000 nest holes which is believed to be at least two-thirds of all nests in the Central Panay Mountain Range. [6] In areas where their large nesting trees have been logged, Philincon installs nest boxes for these hornbills to breed in.

The bird is listed as an EDGE species by the Zoological Society of London where it is ranked as the 50th which uses the basis of evolutionary distinctness and endangeredness. [7]

This bird was bred in captivity for the first time by the Mari-it Wildlife and Conservation Park in 2005. As of 2010, they have bred 15 Walden's hornbills. In 2019, The Talarak Foundation has also successfully bred them in captivity in their Negros facility after nine years of attempts. [8]

Further conservation actions proposed are: more funding should be allocated primarily to in situ protection along the lines of PhilCon's guarding scheme; conduct further surveys, particularly on Panay to identify important sites and use this data to decide further actions; continue community awareness programmes to reduce hunting and illegal logging on both Negros and Panay; work in partnership at the government level to strengthen protected area legislation and improve the network in the long term; and support the development of captive breeding and reintroduction programmes. [4]

Related Research Articles

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

Hornbills are birds found in tropical and subtropical Africa, Asia and Melanesia of the family Bucerotidae. They are characterized by a long, down-curved bill which is frequently brightly coloured and sometimes has a horny casque on the upper mandible. Hornbills have a two-lobed kidney. They are the only birds in which the first and second neck vertebrae are fused together; this probably provides a more stable platform for carrying the bill. The family is omnivorous, feeding on fruit and small animals. They are monogamous breeders nesting in natural cavities in trees and sometimes cliffs. A number of mainly insular species of hornbill with small ranges are threatened with extinction, namely in Southeast Asia.

<span class="mw-page-title-main">Visayan hornbill</span> Species of bird

The Visayan hornbill is a hornbill found in rainforests of Western Visayas region which includes the islands of Panay, Negros,Cebu and Guimaras, as well as the island of Masbate, and formerly Ticao, in the Philippines. It formerly included all other Philippine tarictic hornbills as subspecies, in which case the common name of the 'combined species' was shortened to tarictic hornbill.

<span class="mw-page-title-main">Wrinkled hornbill</span> Species of bird

The wrinkled hornbill or Sunda wrinkled hornbill is a medium-large hornbill which is found in forest in the Thai-Malay Peninsula, Sumatra and Borneo.

<span class="mw-page-title-main">Negros bleeding-heart pigeon</span> Species of bird

The Negros bleeding-heart pigeon is endemic to the Philippines where it is found on the islands of Negros and Panay. It is critically endangered; continuing rates of forest loss on the two islands where it occurs suggest that it will continue to decline. The population is estimated to be just 50 - 249 mature individuals. The species has an extremely small, severely fragmented population. The bird is listed as an EDGE species under the analysis of the Zoological Society of London.

<span class="mw-page-title-main">Wreathed hornbill</span> Species of bird

The wreathed hornbill is an Old World tropical bird of the hornbill family Bucerotidae, also called bar-pouched wreathed hornbill due to its distinctive blue-black band on its lower throat sac. It is named after its characteristic long, curved bill that develops ridges, or wreaths, on the casque of the upper mandible in adults. Males are black with a rufous crown, a white upper breast and face, and a yellow featherless throat. Females are uniformly black with a blue throat and are slightly smaller than males.

<span class="mw-page-title-main">Bucerotiformes</span> Order of birds

Bucerotiformes is an order of birds that contains the hornbills, ground hornbills, hoopoes and wood hoopoes. These birds were previously classified as members of Coraciiformes. The clade is distributed in Africa, Asia, Europe and Melanesia.

<span class="mw-page-title-main">Rufous hornbill</span> Species of bird

The rufous hornbill, also known as the Philippine hornbill and locally as kalaw, is a large species of hornbill endemic to the Philippines. They are referred by locals as the "clock-of-the-mountains" due to its large booming call which typically occur of every hour. It occurs in moist tropical lowland forest. They are now considered to be a threatened species and its reasons for decline being habitat destruction, hunting and poaching for the illegal pet trade.

<span class="mw-page-title-main">Palawan hornbill</span> Species of bird

The Palawan hornbill is a large forest bird endemic to the Philippines. It is one of the 11 endemic hornbills in the country. It is only found in Palawan and nearby islands of Balabac, Busuanga, Calauit, Culion and Coron. It is locally known as 'talusi' in the language Cuyunon, It is threatened by habitat loss, hunting and trapping for the cage-bird trade.

<span class="mw-page-title-main">Writhed hornbill</span> Species of bird

The writhed hornbill, also known as the Mindanao wrinkled hornbill, is a species of hornbill in the family Bucerotidae. It is endemic to humid forests on the Philippine islands of Mindanao, Dinagat and Camiguin Sur. It formerly included the Walden's hornbill as a subspecies, but unlike that species, both sexes of the writhed hornbill have orange-red throat and peri-ocular skin.

<span class="mw-page-title-main">Narcondam hornbill</span> Species of bird

The Narcondam hornbill is a species of hornbill in the family Bucerotidae. It is endemic to the Indian island of Narcondam in the Andamans. Males and females have a distinct plumage. The Narcondam hornbill has the smallest home range out of all the species of Asian hornbills.

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

The oriental pied hornbill is an Indo-Malayan pied hornbill, a large canopy-dwelling bird belonging to the family Bucerotidae. Two other common names for this species are Sunda pied hornbill (convexus) and Malaysian pied hornbill.

<span class="mw-page-title-main">Sulu hornbill</span> Species of bird

The Sulu hornbill, or Montano's hornbill, is a species of hornbill in the family Bucerotidae. It is endemic to the Sulu archipelago in the Philippines, with the remaining populations in Tawi-Tawi with it believed to be hunted to extinction on Jolo. Its natural habitat is tropical moist forests. It is threatened by habitat loss as well as potential harvesting for food. Its diet includes fruit, insects, and small lizards.

<span class="mw-page-title-main">Mindoro hornbill</span> Species of bird

The Mindoro hornbill is a species of hornbill in the family Bucerotidae. It is endemic to forests on Mindoro in the Philippines found in tropical moist lowland forests. As is the case with all Philippine tarictic hornbills, it was once considered a subspecies of P. panini. It is the only tarictic hornbill where both sexes are creamy-white and black. The sexes are very similar, differing primarily in the colour of the ocular ring. It is threatened by habitat loss, and is consequently considered endangered by the IUCN.

The flame-templed babbler is a species of bird of the family Zosteropidae, in the genus Dasycrotapha. It is one of the most remarkable and distinctive birds with its complex head markings with orange crown tufts, black ears and yellow beak and face. It is endemic to the Philippines, where it is found on the islands of Panay and Negros. Its natural habitat is tropical moist lowland forest. It is threatened by habitat loss. Along with the Negros striped babbler, it is one of the two babbler species extremely sought after by birdwatchers on Negros.

<span class="mw-page-title-main">Palawan striped babbler</span> Species of bird

The Palawan striped babbler is a species of bird in the family Zosteropidae. It is endemic to the Philippines, where it is only found in Palawan.

The Negros striped babbler is a species of bird in the family Zosteropidae. It is endemic to Negros Island (Philippines).

<span class="mw-page-title-main">Negros scops owl</span> Species of owl

The Negros scops owl, also known as the Visayan scops owl, is an owl, endemic to the islands of Negros and Panay in the Philippines, belonging to the family of the typical owls Strigidae. It was formerly classified as a subspecies of the Philippine scops owl. It is threatened by habitat loss and hunting for the pet trade.

Sibalom Natural Park is a 5,511.47-hectare (13,619.1-acre) protected area in the Philippines on the island of Panay in the municipality of Sibalom, Antique. It was proclaimed a natural park on 23 April 2000. It is considered one of the last remaining lowland rainforests on Panay.

References

  1. BirdLife International (2018). "Rhabdotorrhinus waldeni". IUCN Red List of Threatened Species . 2018: e.T22682517A125519634. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22682517A125519634.en . Retrieved 13 November 2021.
  2. "Talarak Big 5". Talarak Foundation.
  3. "Writhe-billed Hornbill". Ebird.
  4. 1 2 International), BirdLife International (BirdLife (2016-10-01). "IUCN Red List of Threatened Species: Rhabdotorrhinus waldeni". IUCN Red List of Threatened Species. Retrieved 2021-09-15.
  5. Rufous-headed Hornbill. BirdLife International. Accessed 2008-10-08.
  6. 1 2 "Nest Guarding – PhilinCon" . Retrieved 2021-09-15.
  7. "Rufous-headed Hornbill".
  8. Gomez, Carla (6 May 2019). "Negros zoo succeeds in breeding critically endangered hornbill". Inquirer News.