In what season do swallows fly?

Swallow is a general term for 74 species of passeriformes. Small size, narrow wing tip, short beak and concave tail, weak feet and few feathers. Feathers are monochromatic, blue or green, with metallic luster; Most kinds of men and women are very similar. Swallows spend a lot of time catching pests in the air. It is one of the most flexible birds, mainly feeding on insects such as mosquitoes and flies, and is a well-known beneficial bird. Nest in tree holes or cracks, or make holes in sand dikes, or stick mud on walls or protrusions of corridors, roofs, eaves, etc. In urban and rural areas. Each lays 3 ~ 7 eggs.

Spring, the first of the four seasons, refers to the period from beginning of spring to long summer, including solar terms such as beginning of spring, rain, fright, vernal equinox, Qingming and Grain Rain. Spring represents warmth and growth. In spring, the qi of yin and yang begins to change, and everything germinates with the rise of yang. As far as solar terms are concerned, spring in China begins in the beginning of spring (February 2-5) and ends in the long summer (May 5-7). In Europe and America, spring begins at the vernal equinox in China and ends at the summer solstice. In Ireland, February to April is designated as spring.