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According to ancient medical text, bird nest has sweet taste, neutral characteristic, good for lung and stomach, and is usually used to supplement nutrition. Bird nest is especially good for recovery from debilitation, exhaustion, anorexia, low blood pressure, fever, insomnia, high heart rate, weight loss, icterus, asthma, etc. Moreover, bird nest also enhances the immunity system, eyesight, reduces aging and empowers the mind. The profession of harvesting bird nests from caves in Chàm islands (“Cù Lao Chàm” in Vietnamese) have existed since long ago. In the feudal age, the management and harvest of bird nests in Chàm islands were conducted by villagers of Thanh Châu. The village formed cave guard crews and harvested bird nest for tribute to the imperial court. Due to its special place in the folk culture and national history, the bird nest harvesting profession of Thanh Châu has been recognized as a national intangible cultural heritage by Ministry of Culture, Sports and Tourism. Since 1975, Cù Lao Chàm – Hội An bird nest harvesting, processing and commercialization have been managed by People’s Committee of Hội An city through Hội An Bird Nest Management and Harvest Committee. 

 

Picture 1: Bird nest, packaged and labelled 

  

Cù Lao Chàm – Hội An bird nest has lotus shape, a distinctive smell with no strange smell, and a slightly salty and fatty taste. Depending on the nest condition, colour, impurity level, thickness and weight, they are categorized into three types: “Quan” (the nest root and body is intact; opaque white colour; visible impurity is under 5%; nest thickness 3.0 ± 0.3 mm; weight over 10.5 gram per nest), “Thiên” (the nest root and body is intact; white and slightly opaque colour; visible impurity is under 5%; nest thickness 2.5 ± 0.2 mm; weight 8.5 – 10.5 gram per nest) and “Bài” (nest body is intact; visible impurity is under 10%; nest thickness 2.0 ± 0.3 mm; weight 6.5 – 8.5 gram per nest). Furthermore, Cù Lao Chàm – Hội An bird nest has peculiar characteristics in Protein content (50.07 ± 1.29 %), lipid (1.72 ± 0.11 %), NaCl (1.97 ± 0.14 %), Magnesium (1.457.4 ± 50.9 mg/kg), Calcium (6.918.8 ± 315.1 mg/kg) and Zinc (2.47 ± 0.41 mg/kg). 

  

 

Picture 2: Bird nests by category 

  

The reputation and peculiarity of Cù Lao Chàm – Hội An bird nest are thanks to the natural conditions of the geographical area. It consists mostly of mountains of 70 – 200 m height. The eastern flank of the islands are steep crags (30° – 60°), on which there are gaps and rock shelters for swiftlets. The annual average temperature is 25.6°C, temperature variance between day and night is 5 – 7°C. The annual average humidity is 83%. During the dry season from February to August, it is 75%, and during the rainy season from September to January, it is 85%. The humidity and pleasant temperature are favourable conditions for swiftlets to thrive and make nests. The absence of cold winters provides an ideal environment for the birds and prevent migration. Most of swiftlet caves have Eastward entrance and receive East wind which helps moderating the atmosphere in the caves. Cave humidity is 77 – 90% which makes nest harvesting and preserving nest quality easier. 

      

Picture 3: Typical swiftlet cave entrances 

  

Moreover, the geographical area has a diverse ecosystem. Chàm islands are ones of a few islands in Viet Nam that are able to maintain a high forest coverage at 60-70%. It is a shelter of many animals, including 12 mammal species, 13 bird species, 130 reptile species and 5 caecilian species. The sea of Chàm islands has 124 types of coral, 184 fish species, 23 crustacean species, 116 types of mollusk, and various types of plankton. This is a unique level of biodiversity that no other area in which “Hàng” swiftlets live has. The biodiversity creates an abundant and diverse food source for the swiftlets. 

Aside from the natural factors, the bird nest harvest and processing techniques also ensure the quality of “Cù Lao Chàm – Hội An” bird nest. The harvesting is especially dangerous and requires a certain level of dexterity from the harvesters. At the beginning of the harvest season, the harvest team prepares the boats, equipment and food. They use large bamboo sticks to make scaffoldings in the cave. Next, they have to check the nests and spray water to the cave wall from the bottom to the top of the wall to make the nests softer. Harvesting bird nests are dangerous and requires the harvesters to dangle on the ropes, traverse through the small gaps in the caves. It requires the dexterity and experiences of the harvesters. 

    

Picture 4: Preparing for harvesting 

  

The harvests are conducted in two terms, from mid April to early May (when 2 eggs are laid), and from mid August to early September (when the young birds have left the nest). The nests and eggs must not be broken when harvested. It is done from 9 A.M. to 3 P.M. in 4 – 5 consecutive days. After the harvest is completed, the harvesters must check and remove threats to the swiftlets and their ability to remake their nests. After each day, the nests are transported back to the mainland and kept in specialized storages in room temperature to keep the nests’ moisture. 

   

Picture 5: Harvesting bird nest 

  

After each harvest, some harvesters will stay back to clean the cave and retrieve the equipment. After both harvests, personnel of Hội An Bird Nest Management and Harvest Committee will take turns in guarding the swiftlet caves, even in harsh weathers and holiday to prevent the birds from being stolen, lured away or otherwise sabotaged. 

The processing is conducted after the harvest season. It is done by carefully removing feathers, feces, mud, moss, etc. on the nest using sharp knives or tweezers without cracking, breaking the nest or the root. After processing, purity check and weighing, the nests are sorted by organoleptic characteristics. Processed and sorted products are moved to cold storage and remove moisture until it is 7 – 10%. 

   

Picture 6: Preliminary processing of bird nest 

  

Geographical area: Lao island, Khô Mẹ island, Khô Con island, 

Lá island, Dài island, Mồ island, and Tai island of Tân Hiệp commune, Hội An city, Quảng Nam province./. 

  

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