One day in June, Isaac and Casey were walking through the forest. Bright spears of sunlight pierced the trees. Birds sang above them and chattered like school children. What is the meaning of the underlined metaphor in the excerpt?

A metaphor is a comparison of unlike things such as sunrays to spears and birds to children.

Explanation:

There are two metaphors in the excerpt.

1) Bright spears of sunlight pierced the trees.

This means that the rays of light were so sharp that they reached every where from in between the trees or the trees were no shelter for the sun rays as they were so many and bright.

2) Birds sang above them and chattered like school children.

This means that the birds were so happy singing that their chirping resounded more than the school children chattering. School children chatter a lot and their voices can be heard everywhere in the school. Similarly the birds singing filled the skies. The author emphasizes by comparing the birds singing with the childrens' voices.