Mystery Bird Discovered On Indonesian Island
James Owen in England
for National Geographic News
|January 26, 2004|
Scientists exploring an island in Indonesia have found a bird they
believe is new to science.
The bird's DNA is soon to be analyzed to determine whether it's a new species or a radically altered subspecies, descended from castaways blown from another island. To complicate things further, the bird could also be an as-yet-unidentified pet trade escapee.
This, however, is highly unlikely, according to Nicola Marples, zoology lecturer at Trinity College, Dublin, Ireland.
"It's almost certainly a new species, or the first ever subspecies of the pale-bellied white eye," she said. "While it could also be a feral escape population from elsewhere, we don't think this is the case as we've found no other bird that matches its description."
Marples, as part of a team led by fellow zoologists David Kelly, from Trinity College, and Martin Meads, a freelance researcher, discovered the bird last summer on Wangi Wangi island in southeast Sulawesi.
Meads says the bird, known provisionally as the Wangi Wangi white eye, is found only in one area, near the village of Wanci. He added, "Our surveys, which were conducted over a seven-day period, never recorded the species in any other part of the island."
Sulawesi is of great scientific interest as it forms part of a zoogeographical zone known as Wallacea. The region marks the boundary between Oriental fauna and distinctive Australasian animals such as marsupials.
The new find is thought to belong to a group of small, mainly insectivorous birds called white eyes, which are related to warblers. As well as the characteristic white ring around the eye, they usually have green plumage with white, yellow or greyish underparts.
The mystery bird was first spotted in scrubland along with lemon-bellied white eyes (Zosterops chloris). Marples says the species it most closely resembles is the pale-bellied white eye (Zosterops consobrinorum), though there are some striking differences.
"The Wangi Wangi white eye is almost half as big again," Marples explained. "The beak is big and yellow rather than small and black, while it has grey on the breast instead of being entirely white. It also has very pale feet which is most unusual."
The study team suspect the bird evolved into a separate island race having been blown astray and marooned on Wangi Wangi, part of the Tukangbesi archipelago. The nearest known pale-bellied white eye population is on Buton island, over 20 miles (32 kilometers) away.
Marples added, "As the Tukanbesi islands are oceanic [rose from the sea], all bird species present today must have invaded from elsewhere. The white eyes are a famously intrepid family of birds and have colonized numerous islands in the past. It appears that in this case two closely related species [the pale-bellied and yellow-bellied white eye] have colonized and subsequently diverged from their mainland forms. One of these has become larger and the other smaller, and it is likely that is due to their interactions."
This evolutionary process would allow them both to co-exist on the island by exploiting slightly different food resources.
The team observed a similar trend during previous trips to the islands of Buton and Kabaena where, in 1999, they discovered a new subspecies of red backed thrush (Zoothera erythronota kabaena).
However, Marples describes the Wangi Wangi white eye as "massively different" from other white eyes, increasing hopes of it being an entirely new species.
White eyes elsewhere have shown this same ability to reinvent themselves. Scientists suggest they are speciating (becoming genetically distinct) on various islands off northern Australia.
The process appears to echo the famous example of "Darwin's finches" in the Galapagos Islands. Fourteen different finches evolved from a common ancestor, each adapted to suit the conditions of their various islands. They helped Charles Darwin, who visited the Galapagos in the 1830s, towards his theory of evolution by natural selection.
Wallacea is named after Darwin's contemporary and fellow evolutionist, Alfred Wallace, who first identified the region as the zoogeographical boundary between Oriental and Australasian animals. Covering much of eastern Indonesia, Wallacea is remarkable for its high degree of localized endemism and has at least 250 endemic bird species. Scientists believe there are more out there waiting to be discovered.
"The vast number of islands in this region, many of which are remote and inaccessible, means that much basic biological survey and inventory work is still required, together with investigations of threatened birds," states BirdLife International, a UK-based nonprofit bird conservation group.
Expeditions such as the one to Wangi Wangi are doing just that. They form part of Operation Wallacea, an international conservation and scientific research program centered on southeast Sulawesi. Scientists say the Sulawesi region holds a higher concentration of endemic birds than any other place on Earth. Yet many of them are at risk from human pressures.
Marples says the chief threat comes from logging, adding, "The sad thing is that Wangi Wangi is the most trashed of all the islands we've been to, and as far as we could see is the only home of this new bird." It was also a regional center for the pet trademany endangered wild birds used to be sold to be kept in cages.
By highlighting the wealth of unique wildlife living on islands like Wangi Wangi, Operation Wallacea is helping to convince the Indonesian authorities that the remaining forests should be protected.
Marples added, "We hope to persuade them there's money to be made from ecotourism by selling the potential of watching birds in the area."
In that case, the Wangi Wangi white eye should be one more for the birders' checklist.
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