On our last morning we speed-walk the forest to several other possible giant ibis roosts, but the only big birds perched in trees or hunting the marsh are woolly necked storks. Still, I’m glad to know the giant ibis has made a stand here. During the 2003–2004 breeding season, the WCS found five nests; by 2010–2011 the total had almost quadrupled, with 19 nests and 32 successful fledglings, despite a drought. For a bird with an estimated population of just 200 adults, this is heartening news. Multiplying ibis also portends better fortune for Tmatboey. “If the habitat is here, and we can protect the birds, the foreign tourists will come to see the village,’’ says Sary. “We want it to be like this forever.’’
More than any other Asian nation, Cambodia is sustained by water. For at least a millennium it has relied on an annual miracle: a flood that irrigates the kingdom’s abundant rice fields and overfills the Tonle Sap, Southeast Asia’s largest lake and one of the world’s most productive freshwater fisheries. The beneficiaries include some of the region’s rarest wading birds, which breed, feed, and nest in the safety of this unique ecosystem.
Every summer monsoon, the flood-stage Mekong River overflows into a 72-mile-long tributary, pushing upstream and spilling into the Tonle Sap’s shallow basin. Barely a yard deep in May, the Tonle Sap rises more than 30 feet by September, while its surface area swells from 900 to more than 5,000 square miles and the shoreline advances as much as 20 miles inland. The nutrient-rich floodwaters deposit silt and also nurture more than 200 fish species. My destination, Prek Toal, a 154-square-mile IBA along the lake’s northwest shore, supports the largest remaining stork, pelican, and ibis colonies in Southeast Asia.
If Humphrey Bogart ran bird tours on the African Queen, they’d look a lot like this: branches of the half-drowned riverside forest slap at our boat’s pilot house, while the captain periodically dives overboard to clear water hyacinth clogging the propeller. As we push up the winding channel, we pass beneath a treetop nest holding a curious gray-headed fish eagle chick. Common and black-capped kingfishers skip ahead of the boat like neon-blue tracers. I am forced to duck when an Amur falcon strafes the deck, relentlessly diving after birds our chugging boat flushes from the bushes.
I’m accompanied by Yuleng Ly, 34, a lifelong waterman and reformed hunter who is now one of Prek Toal’s 35 rangers. Like most of the staff, Ly once raided this very forest during the winter breeding season for the eggs of waterbirds, which were then hatched and fattened for slaughter as a holiday delicacy during the mid-April Khmer New Year. His current job is “long-term work,’’ Ly explains. “Hunting, you get big money only at one time of the year. Here, you get $5 every day you work.”
At Platform No. 5, a crude ranger station in the heart of the IBA, we tie up at the base of a squat tree and clamber 40 feet up bamboo ladders to a rickety, treetop lookout. As far as I can see, the trees are ornamented with spot-billed pelicans and painted storks, Asian openbills and black-headed ibis, lesser and greater adjutants.
This is only one of Prek Toal’s 16 colonies, Ly tells me. Since ranger patrols began in 2001, bird numbers have soared: Oriental darters grew from 482 birds to 10,874 in 2010, while spot-billed pelicans rose from 1,400 to 2,950 birds—giving Prek Toal the world’s largest colonies for these species. There has also been dramatic growth of species such as the painted stork (from 2,000 to 4,838) and the Asian openbill (1,200 to 27,690). As a Belgian ornithologist once noted, this place is a veritable “bird factory.”
Among this bounty I’ve seen, there’s still a superlative species missing: the so-called “bird of heaven.” For thousands of years the people of Southeast Asia revered the eastern sarus crane as a celestial messenger that collected the souls of the dead bound for paradise. By the 1980s the birds had mostly disappeared, victims of hunting and the illegal wildlife trade. Then, in 1998, Cambodian biologist Sam Veasna rediscovered the crane in a marshland 50 miles northwest of Siem Reap.
This wetland has a story nearly as tragic as that of Veasna, who died of cerebral malaria the following year. It owes its existence to the Khmer Rouge, who used forced labor to transform an ancient Angkor-era causeway into a massive, L-shaped dike stretching 12 miles. Mony estimates as many as 20,000 people perished during the uncompleted project, which was abandoned after Vietnam’s 1979 invasion. The forgotten reservoir became a sanctuary for wildlife, including the endangered Eld’s deer and the regal, five-foot-tall crane. In 2000 Veasna’s find led to the creation of the Ang Trapeang Thmor Sarus Crane Conservation Area, a 50-square-mile IBA.
Chhoam heads north along an unsealed reservoir road flanked by fallow rice fields and a village populated by former guerrillas. Spying a cluster of cranes in the distance, we swing off the causeway to close within a half-mile of the flock. Through Mony’s scope I can make out the scarlet heads of nearly 20 sarus cranes as well as a half-dozen Eld’s deer.