Hierococcyx is a little genus of birds within the cuckoo household Cuculidae.

Developed in 1845, the genus presently consists of 9 clinically acknowledged types.

Typically called hawk-cuckoos, they can be discovered in South, Southeast, and East Asia.

“Within the hawk-cuckoos of the genus Hierococcyx2 tropical and subtropical Asian types form a close-knit set,”stated lead author Dr. Frank Rheindt from the National University of Singapore and his associates.

“They are variably combined into one types or acknowledged as 2 monotypic types: the big hawk-cuckoo (Hierococcyx sparverioidesand the Bock’s hawk-cuckoo or dark hawk-cuckoo (Hierococcyx bocki.”

“These hawk-cuckoos are discovered in forests from the Himalaya and China to South-East Asia.”

Hierococcyx sparverioides is the more prevalent taxon, reproducing extensively throughout montane tropical, subtropical and even temperate mainland Asia and wintering to the south.”

Hierococcyx bocki varieties in the montane forests of Sundaland.”

“Historically, types delimitation in Hierococcyx cuckoos, as in a lot of other birds, has actually been directed by plumage distinctions,” they kept in mind.

“Yet there is just subtle plumage variation throughout these 2 types.”

“Since the 1990s, the taxonomy of numerous tropical and subtropical bird types complexes has actually gone through a transformation with increasing insights into the value of bioacoustic characters for types delimitation.”

“Species restricts within various tropical and subtropical Asian bird types complexes have actually been re-drawn on the basis of bioacoustic proof.”

In their brand-new research study, Dr. Rheindt and co-authors intended to examine the taxonomy of the Hierococcyx sparverioides—Hierococcyx bocki set and to reveal proof for puzzling types.

To do this, they utilized an integrative method based upon bioacoustic, plumage and morphometric information.

They evaluated an overall of 107 sound recordings of these 2 types gotten from online sound libraries.

They likewise evaluated plumage distinctions and morphometric characteristics determined on the basis of a series of museum specimens.

Their analysis discovered an unique, hitherto unnamed population of Hierococcyx bocki living on Borneo that can be separated from other populations mainly by its special three-syllabled primary tune.

Offered the significance of vocalizations in cuckoo taxonomy, they explained this population as a brand-new types to science: Hierococcyx tiganada

“The brand-new types from Borneo carefully resembles its sis types Hierococcyx bocki from Sumatra and Peninsular Malaysia,” the scientists stated.

“The 2 are practically similar aesthetically, however grownups of the brand-new types have a somewhat grayer mantle, specifically the upper mantle towards the crown, causing an unique absence of contrast in between a gray crown and more brownish back that appears in Hierococcyx bocki“

“The finest distinguishing function in between the 2 types is the structure of their brainfever tune– constantly three-syllabled in the brand-new types and two-syllabled in Hierococcyx bocki“

Hierococcyx sparverioides varies from the brand-new types in the exact same characters that set it apart from Hierococcyx bocki,” they included.

Hierococcyx sparverioides Has a two-syllabled brainfever tune.”

“In addition, adult Hierococcyx sparverioides has a bigger body size, is less dark-gray in front of the eye, has a browner mantle less contrasting with the crown, and shows unique dark-rufous spotting on a whitish background on the upper breast (strong rufous without any spotting in the brand-new types).”

According to the researchers, Hierococcyx tiganada occupies montane jungles above 1,000 m elevation.

“Despite the worrying preservation status of lots of South-East Asian birds which count on rain forest environment, Hierococcyx tiganada is most likely not threatened,” they stated.

“While Borneo’s lowland jungles have actually suffered significant loss over the last 3 years, much of the montane forest in the heart of Borneo makes it through thanks to its remoteness and inaccessibility to logging business and other extractive markets.”

Hierococcyx tiganada is fairly popular from 3 basic places in Sabah and one in Sarawak.”

“There are incredibly couple of records from Kalimantan, and the types seems truly missing from the Meratus Mountains in South Kalimantan.”

“However, the types is most likely common over large locations of montane northern Borneo, frequently near the border in between Kalimantan, Sarawak and Sabah, and the absence of extensive records most likely shows bad observer protection far from reputable birdwatching locations.”

Hierococcyx tiganada is the very first Hierococcyx types to be explained in the 20th/21st centuries.

“This discovery highlights the continuing value of bioacoustic research study in biodiversity discovery and more raises the biogeographic value of Borneo,” the authors concluded.

Their paper will be released in the Journal of Asian Ornithology

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Frank E. Rheindt et al2025. A brand-new and puzzling types of hawk-cuckoo (genus Hierococcyxfrom Borneo. Journal of Asian Ornithology 41: 34-43