Another word which I want to notice is the word "poetry" in the first line.

By the poetry of nature the poet means the voices of nature--the musical sounds made by its idle life in woods and fields.

So the word "poetry" here has especially the meaning of song, and corresponds very closely to the Japanese word which signifies either poem or song, but perhaps more especially the latter.

The general meaning of the sonnet is that at no time, either in winter or in summer, is nature silent.

When the birds do not sing, the grasshoppers make music for us; and when the cold has killed or banished all other life, then the house cricket begins with its thin sweet song to make us think of the dead voices of the summer.
There is not much else of note about the grasshopper and the cricket in the works of the great English poets.