What characterizes the music of autumn?

The classic poem "To Autumn" by John Keats celebrates the season of autumn with sensual elegance. Each of the three stanzas has a specific emphasis. The first stanza extols the beauty of autumn mainly through visual imagery. In the second stanza, Keats personifies autumn as a beautiful goddess. It is in the third stanza where Keats delineates the various sounds that characterize the music of autumn.
Keats begins by declaring that, like spring, autumn has its own music. He first writes of a chorus of gnats among the trees along the river bank. Lambs bleat from the hillsides, and crickets sing from the hedges. The red-breast, a type of bird, whistles from the garden-croft, which is a field adjoining a house or farm. Swallows flying in the air twitter, which means that they make a type of chirping sound.