We present data on the breeding biology of the largest known colony of Asian House Martin Delichon dasypus, located in the Jiangxi Wuyishan
Nature Reserve at 2,158 m in the Huanggang Mountains, China. Nest surveys conducted in abandoned buildings in a subalpine meadow
during March–August 2007 and 2008 yielded 163 and 132 clutches, from 84 and 82 nests, respectively. Breeding pairs also laid multiple
broods and replacement clutches. Average clutch size was 3.0 and 2.6 eggs for first and second broods respectively. Synchronous hatching
was detected in 79% of clutches. The proportion of eggs hatching was 0.7 and 0.6 for first and second broods respectively, and the proportion
fledging was 0.5 and 0.4 respectively. Nests situated inside buildings were more successful than those situated outside owing to greater
protection from severe weather, which was the major cause of breeding failure. Nest losses caused by severe weather were more pronounced
later in the breeding season.