Robert Penn Warren - Mortal Limit

I saw the hawk ride updraft in the sunset over Wyoming.
It rose from coniferous darkness, past gray jags
Of mercilessness, past whiteness, into the gloaming
Of dream-spectral light above the lazy purity of snow-snags.

There--west--were the Tetons.Snow-peaks would soon be
In dark profile to break constellations.Beyond what height
Hangs now the black speck?Beyond what range will gold eyes see
New ranges rise to mark a last scrawl of light?

Or, having tasted that atmosphere's thinness, does it
Hang motionless in dying vision before
It knows it will accept the mortal limit,
And swing into the great circular downwardness that will restore

The breath of earth?Of rock?Of rot?Of other such
Items, and the darkness of whatever dream we clutch?

Robert Penn Warren

http://www.poemhunter.com/poem/mortal-limit/