The types and sources of bird nests 燕窝的来源及种类

The biggest producers of bird nests are Indonesia, Malaysia, Thailand, Vietnam and China; with China being the country which produces the least. The types of bird nests are actually too many to list down; and its categorizing is also a specialised field. Most categories are based on its quality, cleanliness and appearance. The most basic three types are as follows:
燕窝最大的产区为印度尼西亚、马来西亚、泰国、越南及中国，其中以中国之产量较少。燕窝的种类多不胜数，而其分类亦是一门学问，多是依其质地、清洁程度及外观来分门别类，最基本可分为以下三大类：

官燕 (best translated as Superior Bird Nest) comes from "House swiftlets" (屋燕) or "Cave swiftlets" (洞燕). They are usually made of pure bird saliva, hence there are less debris in them. Its colour is light yellow and after adding water, it will turn soft. It has strong water absorption and can expand up to 7-8 times its original size. It is the highest class of bird nests; and used to be offered to the Emperors of old only.
官燕（产自“屋燕”或“洞燕”）官燕习惯以纯唾液筑成燕巢，所以杂质较少，其色泽微黄，呈丝瓜络样，加水后变软，吸水力强，且能膨胀七八倍，是燕窝中的上品，因过去只用于进贡官府，故称为“官燕”。

毛燕 (best translated as "Feathered Bird Nest") only comes from "Cave swiftlets" (洞燕). This type of swiftlet secrete less saliva, hence it developed a habit of building its nest with its saliva and its feathers. Feathered bird nest has poorer water absorption ability compared with superior bird nest and its colours are also darker. After removing debris and soaking in water, it can be made into products such as "bird nests shred", "bird nests balls" and "bird nests cakes". Because its processing is more complicated, hence its nutritional value and actual value are less than that of superior bird nests.
毛燕（只产自“洞燕”）此类燕子的唾液分泌比较少，所以习惯用羽毛混和唾液筑巢，毛燕的吸水力较官燕弱，且颜色较暗，拣去杂质及泡水后可制成燕丝、燕球及燕饼等产品；因其处理过程较多，所以它的营养价值及价钱亦比官燕为低。

草燕 (best translated as "Grass Bird Nest") comes from "House swiftlets" (屋燕) or "Cave swiftlets" (洞燕). This type of swiftlet has saliva which is naturally and extraordinarily sticky. It is fond of using a combination of weeds and its own saliva to build its nests. Hence this type of bird nests contain a lot of debris; as such its price is also the cheapest among the three types of bird nest. It is mainly used to produce bird nests pieces and shreds. It is more suited to those who are beginning to try taking bird nests or those who eat bird nests long term and so prefer to mix it together with superior bird nests.
草燕（产自“屋燕”或“洞燕”）此类燕子之唾液黏力特强，喜以杂草混和口水筑巢，含大量杂质，所以价钱亦是三类中最便宜，主要制成品为燕碎、燕丝；比较适合刚刚开始试食者或喜欢混合官燕一起食用的长期食用者使用。