According to records made by the Western biologist Medway in 1958, nest gatherers in Sarawak made harvests twice yearly in November and February, and they left the third nests for the swiftlets to hatch their eggs and raise their young.
根據西方動物學者密德威在一九五八年的紀錄，採燕人在沙勞越，每年分別在十一月與二月收集兩次，第三巢則留存著好讓燕子孵育幼雛。