— “hong kong and the united states are the largest importers of nests.  farming of nests is performed in purpose-built structures with recordings of bird calls played on the roof to attract the swiftlets” http://www.insideindonesia.org/current-edition/bird-s-nest-boom http://www.academia.edu/3069371/The_status_and_conservation_of_the_Edible-nest_Swiftlet_Collocalia_fuciphaga_in_the_Andaman_and_Nicobar_Islands