January 14, 2026
JAKARTA – The iconic raptor, the Javan hawk-eagle (Nisaetus bartelsi), is facing mounting risks from habitat degradation that threatens its remaining populations, according to recent findings, as forest loss and land conversion continue across parts of Java.
Dwi Listyorini, an animal development regulation expert from Batu, East Java, said the impact of habitat loss is evident in the changing landscape around her hometown over the past decades. Forested areas surrounding Mt. Arjuno and Mt. Panderman, once dominated by dense vegetation, have been converted into villas, recreation parks and agricultural land.
She said the land conversion has altered natural water systems, triggering floods in parts of the highland city of Batu and affecting wildlife that once thrived in the area, including the Javan hawk-eagle, scientifically known as Spizaetus bartelsi.
As a child, Dwi recalled frequently seeing the raptor circling above her village, an experience that left a lasting impression. Today, she said, sightings of the bird have become increasingly rare.
“Back then, I often saw Javan hawk-eagles circling above our village. I didn’t have to go far to see them. Now I hardly see them anymore,” she said.
Threatened raptor
Forest loss in Java and Bali has placed the endemic Javan hawk-eagle, listed as endangered on the International Union for Conservation of Nature Red List, under growing pressure.
A recent study by Syartinilia Wijaya, a landscape management professor at IPB University in Bogor, found that forest cover in Java declined by 6.5 percent over the past decade, equivalent to a loss of about 638 square kilometers.
“The eagle relies on tall trees, such as rasamala [Altingia excelsa] and puspa [Schima wallichii], for nesting, so forest cover is critical to its conservation,” Syartinilia said.
Her research also found that the raptor is capable of nesting in steep terrain, ridges and mountainous areas, updating earlier studies that suggested the species primarily occupied lowland forests. These habitats, however, are increasingly threatened by land-use change, climate-related impacts and expanding human activity.
As much of its natural habitat has disappeared, Syartinilia said the Javan hawk-eagle has shown a degree of adaptability and can tolerate close proximity to humans under certain conditions.
“As long as it is not disturbed and its needs are met, it can survive near people,” she said.
Field observations in East Java, including areas in southern Malang, have documented eagles nesting close to settlements. In one location, an eagle was observed hunting behind villagers’ houses, while its nest was located about 150 meters from a nearby road.
The key requirement for survival, she said, is the presence of tall trees with open branches that allow the eagle to construct its large nests. This makes the preservation of remaining natural forest cover, particularly mature trees, crucial to the species’ long-term conservation.
Path to recovery: A Javan hawk-eagle has been kept as a pet for about a year before undergoing rehabilitation at the Mt. Gede Pangrango National Park since late September. (PILI Green Network/Wawan Harahap)
“The species is very selective. It chooses to nest in trees with a specific architecture,” Syartinilia said.
Beyond habitat loss, the government’s decision to designate the Javan hawk-eagle as Indonesia’s national bird in 1993 has brought additional risks. According to BirdLife International, the designation increased public attention and interest in the species, including attempts to capture it for illegal trade.
Since 1994, the species has remained classified as endangered. The latest population estimate suggests around 511 breeding pairs spread across 74 habitat patches, covering approximately 10,804 sq km, or about 8.4 percent of Java.
To strengthen protection for the Javan hawk-eagle’s habitat, the Forestry Ministry is preparing seven new conservation areas across Java. These include Mt. Sanggabuana National Park in West Java, Mt. Slamet Grand Forest Park in Central Java and Mt. Lawu Grand Forest Park in East Java.
“Designating conservation areas in Java is crucial to protect the Javan hawk-eagle’s habitat and support the species’ conservation,” Deputy Forestry Minister Rohmat Marzuki said.
Returning to the wild
Conservation efforts for the Javan hawk-eagle also continue through rehabilitation and release programs aimed at returning confiscated or surrendered birds to the wild.
One recent release took place on Dec. 13, 2025, at Situgunung, within Mount Gede Pangrango National Park in Sukabumi, West Java, an area known to support around 16 breeding pairs of the species.
The male eagle, named Raja Dirgantara, had been under rehabilitation since late September after being surrendered by residents of Sukanegara in southern Cianjur, West Java, where it had been kept as a pet for about a year.
Now estimated to be around two years old, the bird showed no physical injuries but required intensive rehabilitation to regain basic survival skills, including feeding and hunting.
“When the eagle arrived, it couldn’t feed on its own and had to be hand-fed. We carried out rehabilitation in stages until it was assessed as ready for release,” said Robi Rizki Zatnika of the Mt. Gede Pangrango National Park.
After a year in captivity, the eagle returned to the forest, flying free once again in a landscape that continues to shrink under mounting environmental pressure.