What does The sedge is withered from the lake and no birds sing mean?

"The sedge is withered from the lake and no birds sing" is a line from the poem "To Autumn" by John Keats. The speaker is describing the beauty of the autumn season and how it is affecting the landscape around him. The sedge, a type of grass that grows in marshy areas, has withered and died, and the birds have stopped singing. This is a sign that the summer is coming to an end and winter is approaching. The imagery in this line creates a sense of melancholy and loss, but also a sense of peace and acceptance of the changing seasons.