Nests (apparently exclusively) in caves that are (partly) inundated by rivers (Rowley and Orr 1962). Nest sites are on narrow ledges within these caves. White-naped Swift is a facultative nest builder (Whitacre 1989), with over three fourths of cases consisting of a nest structure, and the remainder were merely shallow depressions on ledges. Nests mostly circular, two thirds of nests contained plant material, most were made of mud. No saliva is used for nest construction (Rowley and Orr 1962). Nest structures are probably absent in case of cave flooding and the subsequent need to quickly rebuild nest. Clutches generally contain two eggs. Eggs are unmarked white and are variable in size (30 x 21 mm to 43 x 28.5 mm).