It is of hot nature.

Because the main nutrient in bird's nest is protein, which has 1 essential amino acid (lysine) and 3 conditionally essential amino acids, bird's nest is often consumed with sea cucumber and ginseng, which enhances the effectiveness of bird's nest. There are 8 essential amino acids and 13 conditionally essential amino acids that the human body needs.

Expanded Information:

Bird's nest is formed when the saliva secreted by the well developed mucous glands in the throat of the swiftlet condenses into a solid in the air. It is the bird's nest constructed by spitting on the insects, seaweeds, and silver fishes that the swiftlet ingests and digests, and is white in color, so it is called White Bird's Nest or Official Bird's Nest. Yellow Bird's Nest: The entire bird's nest or most of the bird's nest is yellow in color, which is a natural phenomenon.

Some of the bird's nests harvested from caves are also unevenly colored in maroon, blood, brown or brownish-yellow, with darker color at the bottom and lighter color in the middle and edges. It should be clarified that this color does not come from the blood in the swallow's mouth.

Baidu Encyclopedia - Bird's Nest