In this statement, what does summer symbolize?

Summer in this paragraph is more like a rainbow with a pot of gold at the end. Look at the second sentence: "...at the end of summer like a pot of gold". "Doodle and I went down..." also suggests the downward curve of a rainbow. Birds breaking into song are often drawn in pictures of rainbows, and since the last 4 words are "birds broke into song" the rainbow idea is reinforced.