Grasshoppers wings are used for what reason?

It favors wild prairie, hayfields, and pastures over wheat fields and alfalfa fields which may offer its prey too much cover. It requires elevated perches for hunting and a supply of small mammals such as young ground squirrels as prey for its nestlings. The breeding distribution of the Swainson's hawk is tied very closely to the distribution of various small mammals for this reason. In Saskatchewan, for example, the distribution of Richardson's ground squirrel and the Swainson's hawk are precisely the same.