Greater and Lesser Adjutant Storks

With their bald heads, wrinkly skin, and slow gaits, adjutant storks may strike some people as ungainly, but the British Colonial troops that named them saw in these birds a stately manner. In military parlance, an adjutant is a senior captain who stands at attention as his superiors file in; adjutant storks are also known to stand motionless for long periods of time.

Natives of India and Southeast Asia, adjutants breed and feed in flooded forests, tidal flats, and sometimes, city dumps. They are both carnivores and scavengers, hunting fish, frogs, and small snakes in open areas or mud flats, and feeding on carrion—an important role for keeping a landscape disease-free. The birds nest in tall trees, bamboo plantations and on cliffs.

Greater and lesser adjutant storks were once common but began declining in the 20th century due to habitat destruction and poaching. Greater adjutants are now estimated to number only around 1,000; lesser adjutants are more abundant, but still vulnerable to extinction. WCS is working to save these and other waterbirds in Cambodia’s Northern Plains and at Prek Toal, part of Tonle Sap, which is the largest lake in Southeast Asia and home to huge colonies of storks, as well as a million people.

Fast Facts

Scientific NameLeptoptilus javanicus (lesser) and leptoptilus dubius (greater)
  • Greater adjutant stork can grow to six feet tall, with a wingspan of up to eight feet. Lesser adjutant storks grow to four feet tall.
  • Adjutant storks often live in proximity to human populations, usually to their detriment. A related species, the marabou stork of Africa, is better able to tolerate human disturbance and so is faring better.
  • Their digestive systems enable them to swallow and digest large bones.
  • Adjutant stork chicks are born helpless, which means that their mother must provide them with a hearty diet before they can learn to fly and feed themselves.
  • WCS’s Bronx Zoo was the first zoo in the U.S. to breed lesser adjutant storks successfully, and remains one of only two facilities in North America to exhibit them.

Challenges

Adjutant storks are threatened by poaching and habitat loss. Increasingly, their nesting trees are being cut down and their wetlands are being drained and polluted for development. Poachers who are after their eggs and chicks have wreaked havoc on the birds’ populations, particularly in Tonle Sap. There, in the 1990s, a single poacher was caught with more than 1,000 stork eggs in his boat. Heavy commercial fishing on the lake also makes it hard for the birds to find enough to eat, and subjects the birds to accidental snags in nets or on lures. By 2000, these colonies were on the brink of local extinction.

The Indian population is threatened by reduced access to carcasses and foodstuffs. Poisoning of small wetlands to catch fish in the dry forests of Nepal and Cambodia also poses a significant threat. Coastal populations are threatened by large-scale development, including aquaculture and the clearing of mangroves.

The population in Malaysia’s Maludam National Park has been reduced to about half a dozen birds, found between the mangroves and the beach. Greater adjutants are listed as endangered by IUCN, and lesser adjutants as vulnerable.

WCS Responds

In a project established in 2001 by WCS and the Ministry of Environment of the Royal Government of Cambodia, former hunters and egg collectors in Tonle Sap have found new employment as park rangers, monitoring breeding colonies of storks, pelicans, and ibises. This novel approach guarantees an active role for local communities in the conservation of this important seasonally flooded wetland. It’s also helped the globally threatened birds to recover—some species have rebounded 20-fold since the project began.

WCS is also working within the global bird-watching community to monitor adjutant populations, and promoting an ecotourism project for the Cambodian village of Tmatboey focusing on rare birds. In return for jobs with the tourism concessions, local villagers promise not to hunt the birds.

WCS Projects

Birding in Tmatboey, Cambodia

One of Cambodia’s poorest regions is rich in rare birdlife—in particular, the giant ibis and its cousin the white-shouldered ibis. Decades of violent conflict and a remote location kept naturalists and birdwatchers away. But now, birders travel from around the world in the hopes of seeing the ibises and other majestic species.

From the Newsroom

Cambodia Protects Key GrasslandsMarch 18, 2010

Nearly 77,000 acres of critical habitat located near the country’s famed Tonle Sap lake are now protected areas for Sarus cranes, storks, ibises, eagles, and the rare Bengal florican.

The Birds Are BackApril 7, 2008

A single team of park rangers, working round the clock, has helped populations of storks, pelicans, ibises, and other rare waterbirds recover in Cambodia’s famed wetland.

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