Indonesia: Javan hawk-eagles return to Mt. Merapi, population on the rise

Bambang Muryanto, The Jakarta Post 12 Mar 16;

In contrast to the decreasing populations of many rare species across Indonesia, the population of Javan hawk-eagles is increasing in Mount Merapi National Park (TNGM), where they can frequently be spotted circling the volcano.

TNGM forest ecosystem control official Arif Sulfiantoro said that his team had identified three more birds, meaning the park is home to a total of six Javan hawk-eagles.

“In 2014, we recorded only three Javan hawk-eagles in the mountain’s forest conservation area. Now that number has doubled,” Arif The Jakarta Post. “This is incredible news.”

He said that the birds, which are endemic to Java, had been identified by the TNGM research team in two regions. Two were spotted in Plawangan forest in Turgo, Sleman regency, Yogyakarta; the third was located in Kemalang, Klaten regency, Central Java.

Of the six, one is the baby of a couple that nested in Plawangan forest, the only primary forest left on the slopes of Mt. Merapi, near the Kaliurang tourist resort.

Arif said it was possible that the two hawks found in Plawangan forest had come from another forest within TNGM.

“We’re not yet entirely sure where they came from,” he said.

Established in 2004, TNGM covers an area of some 6,410 hectares, straddling four regencies: Sleman in Yogyakarta and Magelang, Klaten and Boyolali in Central Java.

Following the 2010 Mt. Merapi eruptions, the protected species disappeared from TNGM, and no individuals were spotted by the TNGM team until 2011.

In 2012, the team spotted four Javan hawk-eagles, but one went off radar in 2014.

Arif said that identifying the whereabouts of Javan hawk-eagles was difficult because the birds preferred to live in dense primary forest.

They are also shy and often hide behind trees when competitors — black hawks or crested serpent eagles — appear nearby. Other enemies include long-tailed monkeys, who like to steal the hawk’s eggs.

According to Arif, Javan hawk-eagles are easily stressed and reluctant breeders — a female Javan hawk-eagle lays only one egg per year.

In 2013, Yogyakarta Governor Hamengkubuwono released a female Javan hawk-eagle in TNGM, but the park’s team have not come across the bird since.

Yogyakarta-based birdwatcher Lim Wen Sin welcomed the news that TNGM now had six Javan hawk-eagles, noting that the national park could ideally only accommodate between eight and 12 individuals.

“Javan hawk-eagles can cover a territory of 1,500 hectares. The birds still have to share space with other predators within a fairly cramped forest,” Lim said.

The main threat to the continued existence of the Javan hawk-eagle is illegal hunting. Four years ago, some 80 were traded online every year. In 2015, with the species in decline, the number traded had fallen to 60.

The IUCN Red List has listed the Javan hawk-eagle as an endangered status since 1994. Ornithologist Bas Van Balen stated in 2012 that the population of the bird across Java stood between 600 and 900.

During the massive eruptions of Mt. Merapi in 2010, hundreds of wild animals that had lived on the slopes of the volcano left the area, their habitats razed by the activity of the world’s most active volcano

Hundreds of long-tailed monkeys from the scorched Plawangan forest were seen moving out of the area, entering residential areas some 15 kilometers down the slopes.