AMBOSELI NATIONAL PARK, Kenya -- The attack came swiftly and silently in the night.

The lioness bounded over the thatch of acacia thorns that surrounds the Maasai village and headed for the donkey pen.

The predator was clawing at a donkey's haunches by the time men stirred in their dung-covered huts. A warrior confronted the dusty tangle of teeth and fur, and sunk a spear through the big cat's right rear leg.

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Then, as swiftly as she had appeared, the lioness scrambled over a rooftop and vanished in the darkness.

The donkey survived, but the lioness died of its wound. Villagers blame hunger and parched conditions for the late-March attack.

"This wasn't the first time," said Wilson Koite, chief of this encampment of more than 300 people in southern Kenya, near the Tanzania border. "There's no wildlife inside of the park, so [lions] just come into the villages."

When the rains failed for the second straight year in 2009, plants withered to their roots in this critical dry-season refuge. Marshes and the shallow bed of Lake Amboseli, usually fed by seasonal rains and runoff from snow-capped Mount Kilimanjaro, cracked in equatorial sun. With little to eat or drink, more than 70 percent of Amboseli's zebra and wildebeest died of starvation, predation or opportunistic infections.

The onset of long rains in recent weeks has begun to rehydrate Amboseli's landscape. But with their traditional prey diminished in numbers, the park's top predators are targeting livestock and risking death. At least nine Amboseli-area lions have been speared or poisoned to death during the past six months, say wildlife managers and conservationists.

"We suspect that there are many more happening," said Paula Kahumbu, executive director of WildlifeDirect, a Nairobi-based organization founded by conservationist Richard Leakey. "[Predator] attacks have been going on for years, but things are really escalating."

Killing lions and other wildlife is illegal but often goes unpunished in Kenya. If goats or cattle are slain by predators, the government or a handful of nonprofit organizations may compensate herdsmen for the loss. But cash is often not enough to cool tempers.

Violence escalates

In late March, Maasai warriors stalked a lioness into the bush and speared her after she slaughtered cattle south of the park, Amboseli warden Joseph Nyongesa said. In ensuing weeks, conservationists confirmed the poisoning deaths of five Amboseli-area lions and three more near the Maasai Mara National Reserve, 175 miles to the northwest.

At the height of the drought some southern villages were suffering lion attacks several times a week, Kahumbu said. Young lions, apparently unfamiliar with how to hunt natural prey, were also stalking permanent settlements for livestock.

"The rate has declined, but lion attacks continue because their natural prey is still diminished," she added. "It will take a while for wildlife to recover."

A March 2010 aerial census recorded three lions in a 24,000-square-kilometer area encompassing Amboseli and parts of northern Tanzania. A May 2007 census recorded 10 lions.

The population is likely higher, the latest census underscored, as lions are difficult to spot from the air and are most active at night. Kenya Wildlife Service (KWS) officials and conservationists who study Amboseli estimate that the area had about 30-40 resident lions prior to the recent killings.

What's certain, wildlife managers say, is some Amboseli lions are roaming unexpectedly long distances in search of wildebeest, zebra and other wild prey. Six lions fitted with KWS satellite collars have been tracked far into northern Tanzania, said park warden Nyongesa.

"We have heard there are quite a number of lions killed on that side, but most of them are the lions of Amboseli," he said.

Wildebeest and zebra constitute the greatest biomass in Amboseli but suffered the greatest losses during the drought.

The wildebeest population fell by about 83 percent, from 18,538 in 2007 to 3,098 in 2010, according to the aerial counts. Zebra declined by around 71 percent, from 15,328 to 4,432.

The prolonged dry spell also took a heavy toll on livestock.

The area's cattle population is less than half of what it was three years ago, the counts show. Livestock are critical to the Maasai, who build their homes with dung, cover their blades with leather, and fill their bellies with meat, milk and blood.

Maasai elder Kayian Olekiraku said the drought killed all but 20 of his 200 cattle. The same night of the attack in Koite's village another lion broke the leg of one of Olekiraku's bulls before being chased off.

"When I was young, we just killed the lion," he recalled at the edge of his hardscrabble village. "Now we don't. We fear the government will take us to jail."

'Predator proof' fences

Wildlife service officials say they have been meeting with southern Kenya residents over the past few months to discuss better animal husbandry practices and changes to the ecosystem.

"We had to calm down the situation by talking to them," said KWS senior scientist Charles Musyoki. "We know they are incurring losses, but we needed to talk to them so that they don't retaliate by killing the animals."

In February, the wildlife service launched nationwide strategies for managing lions, cheetahs, hyenas and wild dogs. The plans are intended to preserve ecologically viable predator and prey populations inside of reserves, create carnivore conservation zones outside of government-protected areas and cull animals that attack livestock repeatedly.

Maasai herdsman Ole Saitoti plants kai apple behind a chain-link fence he installed around his livestock recently with the help of the Anne K. Taylor Fund. Since the start of the year, the U.S.-based nonprofit has helped fortify 70 village bomas against predator attacks near Maasai Mara National Reserve. Photo courtesy of Anne K. Taylor.

In March, KWS and the nonprofits Born Free Foundation and Kenya Wildlife Trust began building demonstration "predator proof" barriers adjacent to Amboseli. The barriers, called bomas, include concentric circles of acacia branches and chain-link fencing, Born Free Foundation CEO Will Travers explained.

"You're using the wall of thorns as a kind of airbag," Travers added. "It slows down the predator, and then there's a fence."

The bomas are modeled after ones Kenyan conservationist Anne Taylor built northwest of the Maasai Mara reserve, an area that has seen significant wildlife poaching and habitat loss over the past decade. Taylor, who owns a house there and runs the nonprofit Anne K. Taylor Fund, has helped bolster 70 bomas with metal fencing since the start of the year.

The Maasai Mara barriers, which include 8-foot-high fences fortified with plants and branches, are 100 percent successful at stopping attacks, she said. Boma owners must provide the labor.

"Compensation is never enough," she added. "They need to stop the predation."

Maasai chief Koite said his people cannot afford to buy metal fencing for their village near Amboseli. Speaking the morning after the lion attack, he vowed to bolster his boma's four gates with bigger branches.

"We can't contribute our own money to fence," Koite added, "so we use just the bush."

Kenyan wildlife managers' most ambitious attempt to reduce human-carnivore conflicts -- bringing prey to predators -- appears to have failed.

Great migration

One crisp February morning, a helicopter swung low over the Soysambu Conservancy near the Great Rift Valley city of Nakuru. Startled zebra ran from the thumping blades, past stick-wielding rangers and into a tarpaulin pen.

KWS rounded up 137 zebra that day and the next and drove the animals 200 miles southeast to Amboseli. The agency planned to move 4,000 zebra and 3,000 wildebeest to Amboseli by the end of the year but halted the translocation effort after moving 700 zebra, according to conservationists familiar with the effort.

The brief operation was over budget, politically motivated and poorly executed, charged WildlifeDirect director Kahumbu, who monitored an initial roundup.

Wildlife service rangers failed to capture entire zebra family groups and condition the animals before releasing them into Amboseli, she said. As zebra typically live in highly sociable harems and herds, she explained, many of the disoriented animals fled the park and died of exhaustion or predation within days.

In February, the Kenya Wildlife Service began relocating zebra from central Kenya to parched Amboseli National Park, near the country's southern border with Tanzania. The exercise, pictured above, was designed to provide prey for the park's carnivores. Photo courtesy of Kenya Wildlife Service.

"They were just panic-stricken and ran off in all directions," Kahumbu added.

KWS officials in Nairobi failed to respond to requests for comment about the translocation project's status and the lion poisoning incidents.

Factor into all of this a warming world and a cold calculation.

Three-quarters of Kenya's annual visitors are tourists, and most head straight from Nairobi to the national parks and reserves in hopes of seeing the Big Five -- a lion, leopard, elephant, buffalo and rhinoceros. Losing lions to spears, poison or starvation threatens Kenya's tourism industry -- revenues peaked at $835 million, coming from more than 1 million air and sea arrivals in 2007, before the regional drought and global economic slowdown.

"Tourism is an important contributor to the economy here, and tourism in Kenya is dependent upon wildlife and protected areas," explained Taye Teferi, the World Wildlife Fund's conservation director for East Africa.

The wildlife service estimates that Kenya has about 1,970 lions, down from about 2,750 in 2002. Kahumbu warned that Kenya's wild lions could go extinct within a decade if the cats continue to lose habitat and prey.

Kenya has lost more than 60 percent of its large wildlife since 1977, despite a ban on game hunting, according to government data. Poaching for bush meat and ivory remain lucrative ventures, in poor, rural areas, conservationists say.

Global warming -- and the specter of deeper and more frequent droughts -- is yet another challenge, scientists from the wildlife service and other organizations contend.

The United Nations' Intergovernmental Panel on Climate Change (IPCC) projects that the portion of arid and semiarid areas in Africa is likely to increase 5 to 8 percent by 2080. Between 25 and 40 percent of mammal species in sub-Saharan Africa's national parks will become endangered, according to one study analyzed by the panel.

To cope with the latest drought -- what some are calling the worst in living memory -- the wildlife service spent $250,000 to build dams and dig boreholes in the Maasai Mara reserve and Tsavo West National Park, 50 miles east of Amboseli.

Kenya Wildlife Service should be investing $5 million annually in such water-storage projects nationwide, agency scientist Patrick Omondi estimated. "That would put us at a level," he said, "where we could at least minimize the impacts of climate change."

Changing climate, changing ways

The Maasai Mara reserve, north of Tanzania's Serengeti, is a critical stopping point in the world's largest overland migration. Omondi and other scientists are watching closely how well the reserve's plants and animals recover from the drought.

Every June to October, millions of wildebeest, zebra and other herbivores slog between the Serengeti and the reserve and cross the muddy Mara River. The circular migration is a major tourist draw and is considered one of 10 natural wonders of the world.

Map of Kenya courtesy of the United Nations. Click on the image for a larger version of the map.

"What triggers the migration is when the rainfall starts," WWF's Teferi explained. "When the clouds start gathering, wildlife know which way to go. ... By the time they get to the Mara River, it is in full flood, and the vegetation is quite green."

When the rains failed last year, the river was critically low and the migration was smaller than it had been in the past, Teferi and others recalled. KWS scientist Omondi guessed that the wildlife were "confused."

To the north, Lake Nakuru receded far from its shore, shrinking critical habitat for pink flamingos, pelicans and hippos. Elsewhere in northern Kenya, watering holes evaporated and hundreds of elephants died of hunger, thirst and exhaustion.

Runoff from more than 19,000-foot-high Kilimanjaro makes Amboseli a critical dry-season refuge, but wildlife service scientist Omondi said he worries whether the park can sustain that role.

"Before, we could predict when we had the long and short rains, but that has changed completely," he added. "Now, we never know when the drought comes."

Water is even changing the pastoralist Maasai, who roam between Tanzania and Kenya.

Amboseli chieftain Koite and his people have lived at the park's southern edge for a decade. A hand-pumped well provides water, and a nearby school teaches children English.

Rather than move the entire village with the herds, just a handful of young warriors roam with the cattle.

"Without water, there is no life," he said. "The well -- that is why we stay here."