A sympatric pair of undescribed white-eye species (Aves: Zosteropidae: Zosterops) with very different origins. O’Connell, D.P., Kelly, D.J., Lawless, N., O’Brien, K., Ó Marcaigh, F., Karya, A., Analuddin, K. & Marples, N.M. 2019. Zoological Journal of the Linnean Society. DOI: 10.1093/zoolinnean/zlz022. VIEW
When I first set my heart on a career as a Zoologist (a decision made with absolute certainty at age 12) I dreamed of following in the footsteps of the great naturalists like Darwin and Wallace, travelling to unexplored places and finding new and incredible species. So it is of no surprise that when I finally got around to starting my PhD many years later, I chose to study speciation, the formation of new species in the course of evolution, in the birds of South-east Sulawesi, Indonesia. Sulawesi is a weird and wonderful part of the world, and island hopping through that region has provided me with a lifetime of unforgettable memories. It also allowed me to fulfil my dream, as in our recent paper in the Zoological Journal of the Linnean Society, we describe two new bird species from the Wakatobi Islands, an island chain off South-east Sulawesi (Fig. 1).
Figure 1 The Islands of South-east Sulawesi. The Wakatobi Islands are the home for the two new bird species, with the Wakatobi White-eye (Zosterops flavissimus) found throughout the Wakatobi Islands and the Wangi-wangi White-eye (Zosterops sp. nov.) only found on the most northern island, Wangi-wangi
The Wakatobi Islands are an oceanic archipelago that have never been attached to mainland Sulawesi. Until the Trinity College Dublin (TCD) bird group lead by Prof Nicola Marples and Dr David Kelly began working on the Wakatobi Islands with collaborators from Halu Oleo University (UHO), the Wakatobi Islands had been largely ignored by the scientific community since the early 20th century. The TCD/UHO team found that the islands were home to many bird populations which seemed very different to their relatives on mainland Sulawesi. They trapped birds using mist nets to take measurements of their body size and a few flank feathers for genetic samples before releasing the birds again. This resulted in Kelly et al. (2014) proposing a new species for the Wakatobi Islands, the Wakatobi Flowerpecker (Dicaeum kuehni). However this was not the only unique population, as Prof Marples and Dr Kelly’s attention was also drawn to the white-eye (Zosterops) species of the Wakatobi Islands.
The white-eyes are an incredible group of birds which are among the fastest evolving of all vertebrates, earning them a title as amongst the “great speciators” (Moyle et al., 2009). The name for white-eyes in Bahasa Indonesia is burung kacamata, which literally means spectacled birds. It’s an apt description as the little white ring around their eyes gives them a quizzical bespectacled look. The Wakatobi Islands were thought to be home to a subspecies of the Lemon-bellied White-eye (Zosterops chloris flavissimus). When Prof Marples and Dr Kelly visited the Wakatobi Islands in 2003 they noted that the Lemon-bellied White-eyes there were distinctly different from the ones on the mainland, being far yellower and smaller in size. They also found a mystery white-eye only on the most northern Wakatobi Islands, Wangi-wangi, with a large yellow bill and a white chest, which was unknown to science.
These intriguing populations became one of the main focuses for my PhD work and provided me with some remarkable findings. The Wakatobi subspecies of the Lemon-bellied White-eye was distinctly different from other populations of this species in its genetics, body size and song. The difference in song is particularly important as this is how birds find their mates, so if populations are singing differently they won’t breed and so stay separate. The Wakatobi population has been separate from any other Lemon-bellied White-eye population for at least 400-800,000 years. Therefore we propose it is recognised as a unique species, the Wakatobi White-eye (Zosterops flavissimus). Even more incredibly, I discovered that the mystery white-eye found only on Wangi-wangi Island was a completely novel species, completely genetically distinct, whose closest relatives were found more than >3000 km east of there in the Solomon Islands. We name this species the Wangi-wangi White-eye. Finding such a novel vertebrate species is extremely rare in modern times. The Wangi-wangi White-eye’s only home is a tiny (155 km2) island with a high-density human population, so urgent action is likely needed to ensure the protection of this novel species.
Figure 2 The Wakatobi White-eye (Zosterops flavissimus) © Seán Kelly
As well as the excitement of finding such photogenic new species, this discovery may have important implications for the conservation of biodiversity in Sulawesi! As resources for conservation are always limited conservation organisations prioritise their funding for designated areas which are home to the most unique and rare species. One such designation is the BirdLife International Endemic Bird Areas. In order to be recognised as an Endemic Bird Area a region needs to be home to two species entirely restricted to that area. The recognition of two new white-eye species (along with the Wakatobi Flowerpecker) should make a strong case that the Wakatobi Islands be recognised an Endemic Bird Area and receive greater support from BirdLife International for conservation efforts on the islands. The Wakatobi Islands have experienced a massive increase in human population so all habitats on the islands have been badly damaged. Urgent action is needed to protect the remaining habitats on these islands to protect the Wakatobi’s unique bird species. Doing so will also have knock-on benefits for other species found on the islands such as the Critically Endangered Yellow-crested Cockatoo (Cacatua sulphurea). We hope that our work will help highlight the biodiversity of the Wakatobi Islands and wider Sulawesi region and ensure it is protected as the world faces a looming extinction crisis. TCD and Halu Oleo University are determined to continue to work hard to ensure that some of the stunning wild areas of this region remain intact, and its unique species are recognised!
Figure 3 The Wangi-wangi White-eye (Zosterops sp. nov.; left) and Wakatobi White-eye (Zosterops flavissimus; right) together. Both were trapped on Wangi-wangi Island, measured and then released © Nicola Marples and David Kelly
Thanks to TCD, Halu Oleo University and Operation Wallacea for facilitating, planning and providing logistical support for this research. A big thanks to Kementerian Riset Teknologi Dan Pendidikan Tinggi (RISTEKDIKTI) for providing the necessary permits and approvals for this study (0143/SlP/FRP/SM/Vll/2010, 278/SlP/FRP/SM/Vll/2012, 279/SIP/FRP/SM/VIII/2012, 174/SIP/FRP/E5/Dit.KI/V/2016, 159/SIP/FRP/E5/Fit.KIVII/2017 and 160/SIP/FRP/E5/Fit.KIVII/2017). Finally, we like to thank all of the research assistants who contributed across many field seasons.
Nominate this article for a BOU Science Communication Award.
Kelly, S.B.A., Kelly, D.J., Cooper, N., Bahrun, A., Analuddin, K. & Marples, N.M. 2014. Molecular and phenotypic data support the recognition of the Wakatobi Flowerpecker (Dicaeum kuehni) from the unique and understudied Sulawesi region. PLoS ONE 9: e98694. VIEW
Moyle, R.G., Filardi, C.E., Smith, C.E. & Diamond, J. 2009. Explosive Pleistocene diversification and hemispheric expansion of a “great speciator”. Proceedings of the National Academy of Sciences 106(6): 1863-1868. VIEW
Featured image: The Wangi-wangi White-eye (Zosterops, sp. nov. © James Eaton