A team of ornithologists from the National University of Singapore and Birdtour Asia Ltd. And the University of Queensland described a new and mysterious species of the genus of hawks and cuckoos. The coccyx From Borneo, a large island shared by the Malaysian states of Sabah and Sarawak, the Indonesian state of Kalimantan, and the Sultanate of Brunei.
Breeding range map Herocoxex Pokey From Sumatra and Peninsular Malaysia, The coccyx sp. From Borneo, and Hercoccus sparphriodis. Image source: Aiwat Jirwatanakanuk/Robert O. Hutchinson/James A. Eaton.
The coccyx It is a small genus of birds within the cuckoo family Cuculidae.
This genus was first established in 1845, and currently includes nine scientifically recognized species.
Known as the cuckoo hawk, it can be found in South, Southeast, and East Asia.
“Cuckoo hawks are included in the genus The coccyx“The two tropical and subtropical Asian species form a tight-knit pair,” said the lead author. Dr. Frank Reindt from the National University of Singapore and colleagues.
“They are variously combined into one species or recognized as two monophyletic species: Great hawk cuckoo (Hercoccus sparphrioides) and Bock’s hawk-cuckoo or dusky hawk-cuckoo (Herocoxex Pokey)“.
“These cuckoo hawks are found in forests extending from the Himalayas and China to Southeast Asia.”
“Hercoccus sparphrioides It is the most widespread species, breeding widely across tropical, subtropical and even temperate mountain regions of mainland Asia and wintering in the south.
“Herocoxex Pokey Ranges in the mountain forests of Sundaland.
“Historically, the species was identified in The coccyx They noted that the cuckoo, like most other birds, is guided by plumage differences.
“However, there is only a slight difference in plumage between these two species.”
“Since the 1990s, the taxonomy of many tropical and subtropical bird species complexes has undergone a revolution with increasing insights into the importance of bioacoustic traits for species demarcation.”
“Species boundaries within many tropical and subtropical Asian bird species complexes have been redrawn on the basis of bioacoustic evidence.”
In their new study, Dr. Reindt and co-authors aim to study the taxonomy of these organisms Hercoccus sparphrioides–Herocoxex Pokey Pair and evidence detection for ambiguous species.
To do this, they used an integrative approach based on bioacoustic data, plumage data and morphometrics.
They analyzed a total of 107 audio recordings of these two species obtained from online audio libraries.
They also evaluated differences in plumage and morphometric traits measured based on a series of museum specimens.
Their analysis revealed a distinct, hitherto unnamed population Herocoxex Pokey It is resident in Borneo and can be separated from other inhabitants mainly by its unique three-syllable main song.
Given the importance of vocalizations in cuckoo taxonomy, they described this group as a new species to science: Hierococcus tijanada.
“The new species from Borneo is very similar to its sister species Herocoxex Pokey “From Sumatra and Peninsular Malaysia,” the researchers said.
“The two are almost visually identical, but adults of the new species have a slightly greyish mantle, especially the upper mantle towards the crown, resulting in a distinct lack of contrast between the gray crown and the more brown back seen in Herocoxex Pokey“.
“The best distinguishing feature between the two genres is the structure of their brain fever song – which is always three syllables in the new genre and two syllables in the new genre.” Herocoxex Pokey“.
“Hercoccus sparphrioides It differs from the new type in the same characteristics that distinguish it from it Herocoxex PokeyThey added.
“Hercoccus sparphrioides It also contains a two-part brain fever song.
“Plus, adults Hercoccus sparphrioides It has a larger body size, less dark gray in front of the eyes, a brown mantle that contrasts less with the crown, and shows distinct dark red stripes on a white background on the upper breast (solid red with no stripes in the new species).
According to scholars, Hierococcus tijanada It inhabits mountainous rainforests above 1000 metres.
“Despite the alarming conservation status of many Southeast Asian birds that depend on rainforest habitats, Hierococcus tijanada “He may not be a threat,” they said.
“While lowland rainforests in Borneo have suffered significant loss over the past three decades, much of the montane forests in the heart of Borneo persist thanks to their remoteness and inaccessibility by logging companies and other extractive industries.”
“Hierococcus tijanada It is relatively well known from three general locations in Sabah and one in Sarawak.
“There are very few records from Kalimantan, and this species seems to be truly absent from the Meratus Mountains in South Kalimantan.”
“However, this species is likely ubiquitous over vast areas of mountainous North Borneo, often near the border between Kalimantan, Sarawak and Sabah, and the lack of large-scale records likely reflects poor observer coverage away from well-established bird watching areas.”
Hierococcus tijanada He is the first The coccyx Species to be described in the twentieth and twenty-first centuries.
“This discovery highlights the continuing importance of bioacoustic research in discovering biodiversity and increases the biogeographic importance of Borneo,” the researchers concluded.
they paper It will be published in Asian Ornithology Journal.
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Frank E. Reindt et al. 2025. A new and enigmatic species of cuckoo hawk (genus The coccyx) from Borneo. Asian Ornithology Journal 41: 34-43