White swallow's nests, i.e. the first bird's nests which were built during the Thai cold season, around February-March. These nests are of the purest quality.

Their premium quality precedes that of the so-called ‘blood’ bird's nests (fig.), which are build in the second and third nesting season, when they are affected by the high humidity of the rainy season, which spurs rust from the caves' walls to infiltrate into the nests, turning them red.