Long before anyone climbed for nests, people sheltered here. Archaeological excavations along the Darvel Bay area at the Madai-Baturong cave complex, near the Tingkayu River, have uncovered stone tools and food remains dating back 20,000 to 30,000 years, marking the earliest known human settlement in northern Borneo. Old burial sites dot the cave as well, though the identities of those interred remain unknown to the villagers who live nearby. The limestone hills that house Madai Cave are part of the Baturong Madai Forest Reserve, a geological formation whose cliffs and hollows have been shaped by water and time into one of Sabah's most significant archaeological landscapes.

The harvesting season comes in two windows: February through April, and July through September. During these months, licensed collectors from the Ida'an community make their ascent using equipment that has changed little across centuries. Rattan ladders, ropes, and bamboo poles are bound together in configurations that look precarious and are. The climbers work by headlamp and instinct, prying nests from crevices high in the cave's vaulted ceiling. It is dangerous work. A fall from the upper reaches would be fatal, and the footholds are slick with moisture and bat guano. The demand comes largely from Chinese communities, peaking around Chinese New Year, when bird's nest soup is considered both a delicacy and a health tonic.

The swiftlets share Madai Cave with large colonies of bats, and their combined droppings have created thick phosphate deposits on the cave floor. These too are harvested, collected for use as fertilizer. The cave is, in effect, a multi-layered resource: archaeological site, nest source, and mineral deposit, all occupying the same dark chamber. The ecosystem is delicate. Overharvesting of nests can collapse swiftlet populations, and the Ida'an's traditional management system, which limits collection to specific seasons and specific families, functions as a form of conservation whether or not it was designed as one.

Madai Cave gained international attention in 2000, when it was featured on the American adventure race program Eco-Challenge. Competitors had to climb the cave's rattan ladders, a task that left seasoned athletes clinging and gasping where Ida'an harvesters move with practiced ease. The broadcast introduced millions of viewers to a practice most had never imagined, and to a cave whose significance runs far deeper than spectacle. For the Ida'an, the cameras came and went. The nests keep growing. The ladders keep going up.