Researchers from Ireland and Indonesia and the conservation group Operation Wallacea have described two new species of white-eye, a widespread family of about 140 passerine bird species from Africa, Asia, and Australasia. The new species occur on islands offshore of Sulawesi, a large Indonesian island known for its weird and wonderful plants and animals.
Details of the discovery of the Wakatobi White-eye and the Wangi-wangi White-eye have been published in the Zoological Journal of the Linnean Society, which is the same journal in which Alfred Wallace and Charles Darwin published their original ideas about speciation in 1858.
Zoologists Nicola Marples and Darren O’Connell of Trinity College Dublin and their co-authors from Halu Oleo University and Operation Wallacea say the Wakatobi White-eye is distinct from the more widespread Lemon-bellied White-eye. Genetics, body size, and song distinguish the two species, they say. Lemon-bellied White-eye occurs on mainland Sulawesi while the new species — formerly considered a subspecies of Lemon-bellied — is found on the nearby Wakatobi Islands.
The other new species, Wangi-wangi White-eye, remained unnoticed until September 2003, when Marples’ research group visited the island from which it takes its name.
“The bird survey team were conducting general surveys on the island of Wangi-wangi, when Martin Meads reported seeing a white-eye with a pale-belly,” Marples recalls. “This was unexpected, as the only white-eye species reported from the Wakatobi Islands had a yellow belly. I made a recording of a white-eye flock in the area. When I brought it back to the ringing team, led by Dave Kelly, they had just caught one of these unexpected birds. It was huge in comparison to the other white-eyes it was flocking with, and had a big yellow beak, unlike the small black beak of the Wakatobi White-eyes. We knew straight away that it was new and undocumented in the bird books we were using.
“We took photos and feather samples for DNA analysis, and measured it in all the standard ways (under licence from the Indonesian authorities), then released it. We’ve caught many more Wangi-wangi White-eyes since then, and discovered that it’s only present on the one small island of Wangi-wangi. Currently, there’s no voucher specimen of the species in a museum. It remains an ‘undescribed species.’ This is very frustrating, as conservation efforts generally require species with officially recognized names. Ironically, in order to provide the bird with such a name, a researcher will have to kill one of these birds and deposit its body at an Indonesian museum. These are the rules of the International Commission on Zoological Nomenclature (ICZN). We have approached the ICZN about the case of the Wangi-wangi White-eye, but they are not prepared to accept alternative evidence (e.g. genetics, photos, song, behavior and physical measurements).”
White-eyes as a group have spread and speciated more rapidly than any other birds. They are adaptable, feeding on a wide variety of fruits, flowers, and insects. White-eyes are also supreme island colonizers, which is why so many different white-eye species have evolved so rapidly, as different island populations become isolated and split off from their source population.
The two new white-eye species follow this trend; they are both found on the Wakatobi Islands, just off mainland South-east Sulawesi. However, the two species could not be more different. The Wakatobi White-eye is found throughout the Wakatobi Islands and split from its mainland relatives in the last 800,000 years. In contrast, the Wangi-wangi White-eye is a much older species found on only one tiny island, with its closest relatives found more than 3,000 km away, in the Solomon Islands. While this is an incredible discovery, living on only one tiny island means the Wangi-wangi White-eye is vulnerable to habitat loss.
O’Connell, the lead author of the journal article who is now with the University College Dublin, shared details about the birds’ ranges in this Twitter thread.
“To find two new species from the same genus of birds in the same island is remarkable,” says Marples, a professor in zoology at Trinity’s School of Natural Sciences. “The Wangi-wangi White-eye is a particularly special discovery, as it is found on only one tiny island and its closest relatives live more than 3,000 km away.”
“These discoveries are not just of evolutionary interest – they will also be of real conservation relevance,” O’Connell adds. “By highlighting the unique species special to the Wakatobi Islands we can help safeguard the remaining habitats on the islands, which are under huge pressure. We ultimately hope to have the islands recognized as an Endemic Bird Area so that they receive more conservation support.”
I asked O’Connell if he has population estimates or Red List recommendations for the two new species. He writes:
“For the Wangi-wangi White-eye, we have estimated there are about 200 breeding pairs from our surveys of the island. However, our focus was on catching individuals to measure (before releasing them) for our taxonomic assessment, rather than assessing population size, so that is only a rough estimate. We would strongly recommend structured transects across Wangi-wangi Island to ascertain the full population size of this species. This would be very achievable as the island is only 155 square kilometers. Additionally, the Wangi-wangi White-eye was only found reliably in a few locations inland on Wangi-wangi Island, and was never found near the coast, so it is likely only found on patches of the island. We would recommend that the Wangi-wangi White-eye be considered Endangered or Vulnerable due to it being found on only one small (155 sq. km.) island, its small estimated population (~200 breeding pairs) and the fact that Wangi-wangi Island has been severely ecologically degraded, with only patches of forest remaining. The last time any of our research group visited Wangi-wangi was 2012, so the need for an updated assessment is urgent to understand the status of this species and safeguard its future.
“Thankfully there are no such worries for the Wakatobi White-eye. It is relatively range restricted, being only found on the Wakatobi Islands chain (of which Wangi-wangi is the most northern island), which totals about 823 square kilometers. However, it is very adaptable, and is present in huge numbers in most habitats on the Wakatobi Islands, so it is probably of Least Concern.”