A staff of ornithologists from the Nationwide College of Singapore, Birdtour Asia Ltd., and the College of Queensland has described a brand new and cryptic species of the hawk-cuckoo genus Hierococcyx from Borneo, a big island shared by the Malaysian states of Sabah and Sarawak, the Indonesian state of Kalimantan, and the sultanate Brunei.
Breeding vary map of Hierococcyx bocki from Sumatra and Peninsular Malaysia, Hierococcyx sp. from Borneo, and Hierococcyx sparveriodes. Picture credit score: Ayuwat Jearwattanakanok / Robert O. Hutchinson / James A. Eaton.
Hierococcyx is a small genus of birds inside the cuckoo household Cuculidae.
First established in 1845, the genus presently contains 9 scientifically acknowledged species.
Generally referred to as hawk-cuckoos, they are often present in South, Southeast, and East Asia.
“Inside the hawk-cuckoos of the genus Hierococcyx, two tropical and subtropical Asian species kind a close-knit pair,” mentioned lead creator Dr. Frank Rheindt from the Nationwide College of Singapore and his colleagues.
“They’re variably merged into one species or acknowledged as two monotypic species: the large hawk-cuckoo (Hierococcyx sparverioides) and the Bock’s hawk-cuckoo or dark hawk-cuckoo (Hierococcyx bocki).”
“These hawk-cuckoos are present in forests from the Himalaya and China to South-East Asia.”
“Hierococcyx sparverioides is the extra widespread taxon, breeding extensively throughout montane tropical, subtropical and even temperate mainland Asia and wintering to the south.”
“Hierococcyx bocki ranges within the montane forests of Sundaland.”
“Traditionally, species delimitation in Hierococcyx cuckoos, as in most different birds, has been guided by plumage variations,” they famous.
“But there may be solely delicate plumage variation throughout these two species.”
“For the reason that Nineteen Nineties, the taxonomy of many tropical and subtropical chook species complexes has undergone a revolution with rising insights into the significance of bioacoustic characters for species delimitation.”
“Species limits inside quite a few tropical and subtropical Asian chook species complexes have been re-drawn on the premise of bioacoustic proof.”
Of their new research, Dr. Rheindt and co-authors aimed to analyze the taxonomy of the Hierococcyx sparverioides–Hierococcyx bocki pair and to uncover proof for cryptic species.
To do that, they used an integrative strategy based mostly on bioacoustic, plumage and morphometric information.
They analyzed a complete of 107 sound recordings of those two species obtained from on-line sound libraries.
Additionally they assessed plumage variations and morphometric traits measured on the premise of a collection of museum specimens.
Their evaluation unearthed a definite, hitherto unnamed inhabitants of Hierococcyx bocki residing on Borneo that may be separated from different populations mainly by its distinctive three-syllabled predominant tune.
Given the significance of vocalizations in cuckoo taxonomy, they described this inhabitants as a brand new species to science: Hierococcyx tiganada.
“The brand new species from Borneo carefully resembles its sister species Hierococcyx bocki from Sumatra and Peninsular Malaysia,” the researchers mentioned.
“The 2 are virtually an identical visually, however adults of the brand new species have a barely grayer mantle, particularly the higher mantle in the direction of the crown, resulting in a definite lack of distinction between a grey crown and extra brownish again that’s obvious in Hierococcyx bocki.”
“One of the best distinguishing function between the 2 species is the construction of their brainfever tune — at all times three-syllabled within the new species and two-syllabled in Hierococcyx bocki.”
“Hierococcyx sparverioides differs from the brand new species in the identical characters that set it aside from Hierococcyx bocki,” they added.
“Hierococcyx sparverioides additionally has a two-syllabled brainfever tune.”
“As well as, grownup Hierococcyx sparverioides has a bigger physique measurement, is much less dark-gray in entrance of the attention, has a browner mantle much less contrasting with the crown, and displays distinct dark-rufous streaking on a whitish background on the higher breast (strong rufous with no streaking within the new species).”
In keeping with the scientists, Hierococcyx tiganada inhabits montane rainforests above 1,000 m elevation.
“Regardless of the alarming conservation standing of many South-East Asian birds which depend on rainforest habitat, Hierococcyx tiganada might be not threatened,” they mentioned.
“Whereas Borneo’s lowland rainforests have suffered appreciable loss during the last three a long time, a lot of the montane forest within the coronary heart of Borneo survives due to its remoteness and inaccessibility to logging corporations and different extractive industries.”
“Hierococcyx tiganada is comparatively well-known from three normal areas in Sabah and one in Sarawak.”
“There are extraordinarily few data from Kalimantan, and the species seems to be genuinely absent from the Meratus Mountains in South Kalimantan.”
“Nevertheless, the species might be ubiquitous over huge areas of montane northern Borneo, usually close to the border between Kalimantan, Sarawak and Sabah, and the shortage of widespread data probably displays poor observer protection away from well-established birdwatching areas.”
Hierococcyx tiganada is the primary Hierococcyx species to be described within the twentieth/twenty first centuries.
“This discovery highlights the persevering with significance of bioacoustic analysis in biodiversity discovery and additional elevates the biogeographic significance of Borneo,” the authors concluded.
Their paper shall be printed within the Journal of Asian Ornithology.
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Frank E. Rheindt et al. 2025. A brand new and cryptic species of hawk-cuckoo (genus Hierococcyx) from Borneo. Journal of Asian Ornithology 41: 34-43
