SUMMARYTARBURTON, M.K. 1986. Breeding of the White-rumped Swiftlet in Fiji. Emu 86: 214–227.The majority of Fijian White-rumped SwiftletsCollocalia spodiopygius assimilisnest in totally dark caves. Local habitat determines which vegetable materials are cemented into their nests. Colonies examined contained 34 to 7370 nests and eggs were found in these nests only between September and March. The clutch, which was almost invariably two eggs laid three to five days apart, was incubated for 22–24 days. Fifty-eight percent of eggs hatched successfully, and, if the total clutch or brood was lost, it was usually replaced within 14 days. The fledgling success of 92% gave a breeding success of 53% or 1.1 young fledged per breeding pair. Most chick mortality resulted from chicks falling from their nests. There is no sexual dimorphism and both sexes share in incubation and feeding nestlings. New data are compared with those for other Apodidae and Hirundinidae. They show a positive correlation between feeding frequency and the fledging period. Each chick was fed on average only 1.65 times each day, making them one of the least frequently fed of the Apodines. The only ectoparasites observed on the birds or their nests were the tick-like fliesMyophthiria fijiarum.