Some beautiful new bird species discovered on remote Indonesian islands

Zoologists from Trinity College Dublin, working with a research team in Indonesia, have discovered several new species of colorful tropical sunbirds.

Zoologists have identified a new species, the Wakatobi sunbird (Cinnyris infrenatus), which lives on the small Wakatobi Islands in central Indonesia. They also studied the more widespread olive-backed sunbirds and black sunbirds and found that individuals named as such actually belonged to multiple unrecognized species.

Combined, these exciting findings have important implications for our understanding of evolution in this biodiverse region.

Living in the tropics from Africa to Australia, sunbirds resemble American hummingbirds and fill a similar ecological niche. Male sunbirds often have bright plumage, with iridescent or “metallic” feathers that sparkle in sunlight.

For hundreds of years, zoologists have studied the plumage of sunbirds to name species, over 140 of which are currently recognized. However, using new forms of evidence, including DNA, song recordings and statistical analyzes of body measurements, zoologists have revealed that this family is even more diverse than previously thought.

This work was carried out jointly by researchers from Trinity’s School of Life Sciences and Universitas Halu Oleo in Sulawesi, Indonesia, and has just been published in Zoological Journal of the Linnean Society. Fittingly, this journal was the first to publish the evolutionary theories of Charles Darwin and Alfred Russel Wallace in 1858.

The international research team followed in Wallace’s footsteps in more ways than one, as he based his theories on his studies of animals around the islands of present-day Indonesia.

Fionn Ó Marcaigh, first author of the paper and Ph.D. candidate in Trinity’s School of Natural Sciences said: “One of Wallace’s major discoveries is called the ‘Wallace Line’ – a boundary between deep and shallow seas that many animals have failed to cross, leading to significant differences in the species found of The widespread Olive-backed Sunbird appears to be an exception, being found all the way from China to Australia with the Wallace line right in the middle of its range.

“However, the new study showed that the populations from the two countries actually represent two different species, consistent with Wallace’s original predictions. The black sunbird was already known to be a subject of the Wallace lineage, but the new study showed that the population around Sulawesi is a separate species from that in New Guinea.”

Despite this division, the Olive-backed Sunbird covers quite a wide range for such a small bird. The newly discovered Wakatobi sunbird, on the other hand, is restricted to the tiny Wakatobi Islands, off the coast of greater Sulawesi. Small isolated islands like these have their own evolutionary processes and they often produce unique species, as in the famous case of the Galapagos.

Previous work from Trinity’s School of Natural Sciences identified two species of white-eyed birds from the same area, which is recognized by international conservation organizations as a Key Biodiversity Area.

In addition to being genetically unique, the Wakatobi sunbird also has darker plumage, a higher pitched song and shorter wings than the olive-backed sunbird. Its short wings probably contributed to it remaining isolated on the Wakatobi Islands while the Olive-backed Sunbird undertook long-distance colonization over the sea.

Fionn Ó Marcaigh added: “It is amazing that there are still species waiting to be discovered in this region, which has been important to evolutionary biology since Wallace’s time. I am thrilled that we have added to the list of known species from this wonderful part of the world, it is the kind of thing I dreamed of when I first became interested in zoology as a child. Furthermore, this research was a brilliant opportunity to build on classic work with new techniques. It’s especially exciting when we find new findings that support Wallace’s original predictions.”

Dr David Kelly of Trinity University is the paper’s second author. He added: “The identification of the Wakatobi sunbird reminds us that biodiversity is everywhere. This bird is not found in a remote rainforest, but along the scrublands of busy towns and villages. Let’s hope that the children of Wakatobi will be able to enjoy these special birds for generations to come.”