It is understood that there are 20 species of swallows in the world, and there are about 20 species of swallows, mainly distributed in Southeast Asia, northern and eastern Africa, most parts of Europe and parts of North America. There are also 4 species in China and 3 species in Shouguang, among which domestic swallows and golden waist swallows are more common, and these two species are also the majority in Judian Lake area.