Travels with birds in Cambodia’s wild landscapes (Part 1/2)

Text by Anand Krishnan; Images by Chaitanya Deshpande (CD) and Vaibhhav Sinha (VS)

(This is the first of a two-part story on birds and natural history of Cambodia. Take it away Anand!)

Bordered on its north, east and west by Laos, Vietnam and Thailand, respectively, and with a short coastline along its Southern border, the Kingdom of Cambodia is a country of unique geographic and cultural history. The basin of the Mekong river, and in particular the closely associated Tonle Sap (Southeast Asia’s largest freshwater body), with its seasonally inundated floodplain, served as the ‘rice bowl’ of the Angkorian civilization around a thousand years ago. The remnants of this empire are today an internationally famed tourist destination, characterized by atmospheric jungle temples and a singular confluence of Hindu and Buddhist culture. The more recent history of Cambodia has been marked by one of the most horrific genocides of the modern world, an epoch from which the country is still recovering. Yet, the Mekong floodplain and the surrounds of Angkor Wat represent but a small part of Cambodia’s rich natural wealth, which spans large freshwater wetlands, short floodplain grassland, the largest remnants of the unique Indochinese dry dipterocarp forests, and the unique lowland and montane moist evergreen forests of Mondulkiri and the Cardamom mountains. These areas now serve as the last refugia of some of the world’s most unique and threatened wildlife. On a recent trip to Cambodia, we visited (under the auspices of the fantastic Sam Veasna Centre for Wildlife Conservation, guided by the fantastic Mr. Thea) a sampling of some of these natural habitats, which the Centre works to protect: a protected waterbird colony on the Tonle Sap, the floodplain grasslands of Kompong Thom province, and the dry dipterocarp forests of Preah Vihear province in the Northern plains. In this essay, we discuss the environments, the fauna (in particular, the birds), and their biogeography (in particular, several interesting aspects of how the environment of Cambodia has contributed to its unique fauna), and the work that is being done at these places to conserve them.

The shores of the Tonle Sap (left), and shrimping in progress (right) – VS

Waterbirds across Asia have declined over the twentieth century, largely owing to the combined pressures of wetland degradation, loss of nesting trees, hunting and egg-collecting. The waterbird colony at the Tonle Sap, particularly that at the Prek Toal Bird Sanctuary, is one of the largest remaining in Southeast Asia, and is of great conservation significance. This colony is located close to one of the unique floating villages that characterize the Tonle Sap ecosystem, and the inhabitants make a livelihood fishing (and shrimping!) and farming in the surrounding region.

Small boat is the primary mode of transportation in the floating village of Prek Toal (left; VS). The waterbird colony at Prek Toal, as viewed from a watchtower (right; CD). The speck on top of the tree mid-frame is a distant Greater Adjutant on the nest.

Small boats are the primary mode of transport (and conducting business), and members of the community use these boats to transport visitors to a rather precarious wooden watchtower to observe nesting waterbirds. At the time of our visit (January), the water is about 3 meters deep, reaching its driest point in March-April before the inundation of the monsoon raises the water level. Most waterbirds are on their nests at this time, and may be observed feeding or swimming in the surrounding channels, or soaring as the midmorning heat creates thermals. Large populations of cormorants inhabit Prek Toal, as well as one of the largest Southeast Asian populations of the Oriental Darter or Anhinga. This waterbird, also known as the Snake-bird owing to its serpentine neck, has declined considerably over the last century, but may be observed here in good numbers. Large numbers of other waterbirds (the Black-headed and Glossy Ibis, Grey and Purple Herons, egrets, Chinese and Javan Pond-Herons and Asian Openbill Storks) may be observed close to the village. Most of these species were once widespread from the Indian Subcontinent across Southeast Asia, but populations have declined heavily in this latter region. This is particularly true of the spectacular Painted Stork and the Spot-billed Pelican, whose numbers have stabilized at Prek Toal thanks to the conservation work spearheaded by the SVC and the Wildlife Conservation Society. A significant population of the Grey-headed Fish-Eagle also inhabits this ecosystem, and these striking birds may be seen sunning themselves on exposed perches and soaring on thermals in the mid-morning sun.

Waterbirds of Prek Toal: Top row, left to right: An Indian cormorant in flight (VS), Oriental Darters in flight (CD) and perched (VS), Whiskered terns (VS). Second row: Glossy Ibis (on the left) and Great Cormorant in flight (CD), Black-headed Ibis (VS), Asian Openbill Stork (CD), and Purple Heron perched (VS). Third row: Two Painted Storks in flight (VS), a Spot-billed Pelican (VS), a flying Grey-headed Fish-Eagle (VS), and a perched Greater Adjutant. This last is a photo taken by K.S. Krishnan in Assam, India, in March 2010; our sightings were too distant for photographs! Bottom row: A perched Grey-headed Fish-Eagle (CD), two views of a flying Lesser Adjutant (left: VS, right: CD), and a Milky Stork in flight (VS).

The global importance of Prek Toal as both an Important Bird Area and a Ramsar site hinges particularly on its importance for three highly threatened birds. The Lesser Adjutant Stork, a large, bald-headed stork related to the African Marabou, formerly bred from the Indian Subcontinent to Indonesia, but is now highly reduced in numbers to just a few thousand individuals. The population in Cambodia is one of the largest remaining, and as such is crucially important to the survival of the species. Lesser Adjutants may be seen soaring with the other storks, and are easily recognizable by the shape, and black underside of their wings. The huge Greater Adjutant Stork, standing five feet tall, with an 8 foot wingspan, and described by early naturalists as a ‘prodigy of ugliness’, is both imposing and highly endangered. Once breeding in countless thousands across South and Southeast Asia, the breeding colony at Prek Toal is now the only one known outside of Assam, India, both numbering just a few hundred individuals. We observed several very distant individuals on nests through a scope, but further on in the dry season, they may be seen in the channels closer to the village as the water level recedes. Finally, Prek Toal is home to the last remaining population in Southeast Asia of the Milky Stork, a close relative of the Painted Stork. This bird replaces the Painted Stork over the Malay Peninsula (where it is now almost extinct), Sumatra and Java, where less than 2,000 individuals remain. Prek Toal is one of the few places left where the two species overlap (and occasionally hybridize), with fewer than 30 pairs of the Milky Stork here. The latter may be identified by the lack of a diffuse black band across the breast when seen in flight. Further south, the Milky Stork largely inhabits mangrove forests, in contrast to the inland-dwelling Painted Stork, rendering the population in these wetlands all the more interesting (both from a biogeographer’s perspective and in its overlap with a close relative).

There are four species of waterbird soaring in this frame by VS. See if you can tell them apart by size!
The Florican grasslands of Kompong Thom. Photo by VS.

On the Eastern shore of the Tonle Sap lie the seasonally flooded grasslands of Kompong Thom province, one of the last remnants of a habitat that formerly covered the entire floodplain. Formerly existing in close apposition to traditional agricultural practices, land-use changes in the 20th century have drastically reduced floodplain grasslands across Asia, and these final remnants are now under active management to prevent the extinction of their unique fauna. Typically, grazing by mammalian megafauna (together with periodic fires) maintains these habitats, which can rapidly become overgrown and unsuitable for grassland species. Regular burning and management now ensures that these grasslands and their birds survive, and conservation measures are in place to mitigate hunting. The flagship threatened species of this region is the Bengal Florican, a member of the bustard family. The floricans of Asia are characterized by their spectacular jumping displays that males use to attract mates, and are gravely threatened by habitat loss and hunting. Fewer than 1,000 Bengal Florican remain in fragmented grasslands in India, Nepal, and Cambodia, where the subspecies blandini clings to existence. More than 90% of the Cambodian population has disappeared since the 1990s, a decline that could conceivably result in extinction within a decade. By protecting these grasslands using the florican as a flagship species, several other birds find refuge, including the highly threatened Eastern populations of the Sarus Crane, the rare Manchurian Reed-Warbler (which may be found in bushes close by a busy road in this, the largest known wintering population), a diversity of quail, partridge, larks, duck, and several migratory raptors such as the Greater Spotted Eagle and the stunning Pied and Eastern Marsh-Harriers, which may be seen quartering the grasslands in search of their prey. The florican may be found in the grasslands, where they are difficult to spot in spite of the male’s striking plumage. During the breeding season, however, the jumping displays of the males render them very vulnerable to hunters. Colonial hunters in India related tales of killing dozens in a single shoot, and population declines have been reported since the 19th century. Currently teetering at the very brink of extinction (together with their larger cousin, the Great Indian Bustard), the protected area at Kompong Thom (harboring an estimated 400 individuals) may represent the best hope of their continued survival.

Some birds of the Florican Grasslands: Top left, a Pied Harrier, right, a Black-shouldered Kite. Second row, an Eastern Marsh-Harrier and a Plaintive Cuckoo (all four by VS). Third row, a Green Bee-eater and a Pied Bushchat (both by CD). Bottom row: A distant Bengal Florican in flight, and an equally distant Sarus Crane (both VS).

End of part 1.
You can find Part 2 here.