I have questions about figurative languages. What does "Water hears and understands. Ice does not forgive." really mean? What does Kaz mean from comparing people as "pidgeons" and "crows"?

In the book, Kaz describes (including himself) as pidgeons and crows. Does pidgeons mean people with ignorance and cluelessnes of death and rutheless criminals?

For the Water and Ice, does Ice represent cold brutality and water represent healing the wounds?

Water is important for living, used to hydrate you and lubricating your muscle, while ice and coldness makes your muscles tense.