In the title of the poem, "roosting" suggests the hawk is still, not a swooping bird of prey as we may imagine.
This gives a sense of the hawk meditating on his powers of destruction.
The tone is haughty. The hawk is focused and not distracted - "no falsifying dream".
The language creates a sense of arrogance about the hawk- "I hold creation in my foot" , "it is all mine"
There is a sense of control and that the hawk is playing God throughout the poem- "allotment of death"
"I am going to keep things like this" shows the power that the hawk has. It is a statement suggesting that he is king of the animal kingdom and untouchable.