Traders Cave (Gua Dagang) is a small but historically significant cave situated at the base of the Great Niah limestone massif, visible from the boardwalk trail shortly before the main cave entrance. The cave served as a trading and processing station for the bird's nest industry — the point where collectors emerging from the Great Cave with their harvest would weigh, clean, grade, and sell the nests to traders who transported them by river to coastal ports and eventually to Chinese markets.
The cave's wooden floor structures and plank-framed drying racks were still partially intact when researchers first documented the site in the mid-20th century. Grading bird's nests was skilled work: nests were sorted by colour (white being the most valuable, black nests — bound with feathers — fetching far less), cleaned of feathers and debris, and weighed in standardised measures. The scale of the trade was remarkable. Historical records from the late 19th century describe Niah's annual nest harvest at tens of thousands of catties (one catty ≈ 600 grams), representing significant income for the collector communities living at Batu Niah village.
Today Traders Cave retains some of the original wooden structures, though they are fragile and fenced off. A small interpretive panel at the cave explains the nest-harvesting economy. The cave is not large enough to enter — it is viewed from the boardwalk approach — but the location provides useful context for understanding the relationship between the edible-nest swiftlet and the human communities that have depended on it for over a millennium.
The nest-harvesting tradition continues within Niah under licensed concessions held by families whose rights predate the park's creation in 1974. The tension between conservation and heritage rights is one of the defining management challenges at Niah. Park rangers enforce the rule that nests containing eggs or live chicks cannot be taken, but enforcement inside the cave is difficult given the scale of the structure and the darkness of the harvesting sites. The park's archaeological significance and its living cultural heritage make it one of the most complex management environments in Malaysian protected areas.