The harvesting of edible-nest swiftlet nests from the ceiling of Niah's Great Cave is one of the most demanding traditional occupations in Borneo. Licensed collectors ascend bamboo and rattan poles lashed together in long sections — reaching 55–60 metres to the cave ceiling — in near-total darkness, working by headlamp or kerosene lantern, their feet and hands gripping the smooth rattan in positions that require extraordinary core strength and calm. A fall from 60 metres onto the guano floor is invariably fatal; deaths have occurred within living memory.
The poles themselves are engineering achievements. Individual sections of bamboo and rattan are joined with lashing and propped against the cave ceiling at specific nest-cluster sites. Each collector family holds rights to specific sections of the cave ceiling — rights inherited across generations and predating the park's establishment. The poles are erected at the start of each harvest season (typically twice yearly, between nest cycles when the birds have vacated) and dismantled afterward to prevent deterioration from the humid cave atmosphere.
At the ceiling, collectors work in cramped, inclined positions, using a long-handled tool to detach nests from the rock. White nests — made from pure saliva without feathers — fetch the highest price: up to USD 2,500 per kilogram wholesale in 2024. Black nests, made from saliva mixed with the bird's own feathers, are worth perhaps one-tenth as much. Collectors typically take 2–4 hours per session inside the cave and can harvest 3–5 kilograms of nests per trip. The work is seasonal, exhausting, and genuinely dangerous.
Park management at Niah attempts to balance this heritage tradition against conservation goals. The fundamental tension: swiftlet populations inside the cave need undisturbed breeding periods, but harvest concession holders argue their rights predate the national park. The current management plan allows harvest of unoccupied nests twice yearly, prohibits harvest of nests containing eggs or chicks, and requires collectors to register each entry. Compliance is monitored but difficult to enforce in the cave's darkness. The tradition is described in detail at the Traders Cave interpretive display on the boardwalk.