For Hopkins, a Jesuit priest, nature is a creation of God, but in man's control; it is good and knowable. The poem is dedicated "To Christ Our Lord." Look at the specificity and perfect vision of the speaker in "Windhover":
I CAUGHT this morning morning’s minion, king- dom of daylight’s dauphin,
For the more secular Hughes, nature is observable but not as knowable. Observe the speaker, a hawk, in "Hawk Roosting":
eyes closed. / Inaction, no falsyfing dream
So, Hopkins' speaker (a man) keenly observes the bird as the bird itself observes the world: both man and bird are part of nature, God's creation. For Hughes, the speaker (a bird) is less sensate, and it relishes its own creation from a kind of evolutionary perspective:
Now I hold Creation in my foot
Look at the way the Enotes editors comment on the poets natural subjects:
[Hopkins] thought that all individually beautiful things had within them a principle of growth by which they developed, which he called “instress,” a curve of stress that entered matter and transformed it into an individual creation.
[Hughes'] first volumes of verse contain individual poetic statements on the nature of the created world, focusing on particular animals, plants, people, and seasons. These poems are intended as explorations of identity, of the “thing in itself”—following closely the late Victorian poet Gerard Manley Hopkins, whose emphasis in much of his nature poetry was on the “this-ness” or “selfhood” of each created being.
AND, to conclude:
While Hopkins saw such creation as manifestations of the variety and infiniteness of the Creator, Hughes denied the existence of divinity.