After the beginning of spring, the weather gradually gets warmer, and sparse, green new leaves begin to grow on the branches of bare deciduous tree species. Evergreen tree species and bamboo forests are mixed in the deciduous forest; willow warblers and tree warblers (birds) Passeriformes/a small songbird of the family Sylviidae) began to be active in the trees and began to sing; barn swallows (scientific name: Hirundo rustica) also began to take the mud from ponds and rivers to build nests under the eaves...