The sparrow's "chirping" means it's a sunny day. When an oriole meows, it's going to rain. The cuckoo's call of "cuckoo, cuckoo" urges farmers to plant seeds in the fields. Seagulls make a loud cry when they are fishing, and fishermen can spot schools of fish according to their cries.

Bird, also known as a bird. Definition: an oviparous vertebrate animal whose body is covered with feathers.

The main characteristics of a bird are: a streamlined (fusiform or pike-shaped) body and a mostly flying life. The body surface is covered with feathers, usually the forelimbs become wings (some species have degenerated wings); well-developed pectoral muscles; a short rectum, a large amount of food is digested quickly, i.e., a well-developed digestive system, which contributes to weight loss and facilitates flight; the heart has two atria and two ventricles, and the number of heart beats is fast. Body temperature is constant. Respiratory organs in addition to the lungs, but also has a number of air sacs to assist in breathing, so that the birds, whether in the inhalation and exhalation, there is oxygen through the lungs, i.e., double respiration.

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