Island queen In search of the rare 'monkeyeating' eagle

In their last stronghold, these endangered birds are under threat from logging, hunting and militant armed groups

- Vincent Mundy

Christian Daug whistles with all the spirit he can muster. "The male and female were perched there yesterday," he says, pointing to a dead tree amid the sea of flora that smothers the tallest mountain on the Philippine archipelago.

He whistles again as we look out over the jungle from a wooden observation post. This area is one of the last remaining strongholds of Pithecophaga jefferyi: one of the world's largest and rarest eagles. Measuring about a metre in height when perched, with a wingspan that can reach more than 2 metres, it is known locally as the "monkey-eating eagle". The enormous raptors prey primarily on macaques, but also feed on pythons, chickens, cats and dogs.

Daug is one of a group of local tribes people who have joined the Philippine Eagle Foundation (PEF) on its monitoring and research mission in Mount Apo natural park on Mindanao island. With only an estimated 392 breeding pairs remaining, scattered in fragments of jungle over three heavily logged Philippine islands, every nest site and bird is precious.

"I wish I could whistle like that," says senior PEF biologist Rowell Taraya. "We've been monitoring the pair near here for two years, but still didn't spot their nest," he says as we trek to the next post. "They aggressively guard their territory - which is huge, every pair needs at least 8,000 hectares - so they are really hard to monitor."

The hours pass, with no sign of an eagle. With daylight fading, we set up our hammocks and sleep.

"New day, new tactics," says Taraya at dawn. "No eagle can resist this." He holds up a wooden cage with a 2-metre-long python inside. Monkeys rustle in the canopy above. Finally: "Eagle!" Taraya whispers, as a raptor swoops above and lands on a branch a few hundred metres away.