There are two types of bird nests – Cave Nests and House Nests. Cave nests are mainly harvested from natural limestone caves, while house nests are harvested from swiftlet farming houses that are designed for the breeding of swiftlets.
Cave Nests can be in white or dull orange red to brownish red color, this red color is result of either the seepage of natural minerals from the limestone cava into the white bird nest or due to oxidation of iron. This makes cave nests have higher mineral content compared to house nests. Besides, due to scarcity of resources and high labor intensity when harvesting, cave nests are usually higher in price. However, due to the uncontrolled environment in natural caves, cave nests contain a lot of impurities. Recent study also shows that nitrate and nitrite level in cave nest is much higher compared to house nest. These factors make cave nests possess food safety concerns.
House Nests are produced under a controlled environment that is ideal for Aerodramus fuciphagus to breed. Clinical study shows that house nest was found to contain higher sialic acid content than EBN from the cave. House nests are only harvested when the young swiftlets have left the nest, ensuring continuous nest production. In other words, harvesting house nests helps prevent ecological problems.
