Higashijima Island doesn’t look like much from the sky. This tiny, uninhabited scrap of land 1,000 kilometers south of the coast of Japan is only a few hectares in size. The eastern half of the island consists of rocky outcroppings, while the western half contains small plots of grassland and shrubs. Nothing about Higashijima appears all that notable.
But Higashijima hides an incredible secret. The island is the only known home to the incredibly rare Bryan’s shearwater (Puffinus bryani), a bird that until recently was feared to be extinct.
The Bryan’s shearwater was only discovered four years ago, when scientists examined two nearly 50-year-old museum samples originally collected in Hawaii and the Midway Atoll. Previously thought to be a little shearwater (P. assimilis), DNA testing revealed the sample to be a previously unknown species. But even the revelation of the new species didn’t answer questions about where the tiny birds bred or if they even still existed.
A few more clues emerged in 2012. With the genetic and morphological descriptions of Bryan’s shearwaters in hand, scientists reexamined six previously unidentified birds found in the Ogasawara archipelago (also known as the Bonin Islands) between 1997 and 2011. Even though the five of the six carcasses had been heavily munched on by invasive rats, researchers were able to identify them as the newly discovered species.
But no new sightings came after 2011. Had rats wiped this species out before we even knew it existed?
Now we know. This February a team from the Forestry and Forest Products Research Institute (FFPRI) in Japan visited Higashijima in the Ogasawara archipelago. After hearing a high-pitched chirp, they started combing through the island’s three hectares of grass and shrubs.
That’s when they found them. All told, the researchers discovered 10 Bryan’s shearwaters, including one that was sitting on an underground nest. They briefly captured and measured four of the birds, photographed some of them, captured a few seconds of video, and then left them to continue with their mysterious ways.
Higashijima appears relatively safe for the 150-gram birds, as Japan’s Ministry of the Environment has already completed a rat-eradication project there. However a new threat has already started to emerge. The island contains invasive plants, which the FFPRI worries could choke off the native plants the birds depend upon for shelter. The organization is starting a project to remove the plant before it causes more damage the islands.
Meanwhile, they’ll keep looking for more Bryan’s shearwaters on other islands in the archipelago. Will the researchers find more? Will the birds that we know about remain on Higashijima or do they still fly 4,000 kilometers to Midway every year? What will it take to protect them? Those and other questions remain to be answered.
Photo: Forestry and Forest Products Research Institute