Oh, thank you, Mews! Yes, I love that passage, too. Easpecially,

And even as he spied them and came swooping down, he saw them fall, worn out, or choked with fumes and heat, or stricken down by despair at last, hiding their eyes from death.

"Oh, please," I always sob, "not, 'hiding their eyes from death'!"

How brilliant of Tolkien to offer that list of possibilities for what Gwaihir - and the reader - might see as they look down at the heroes, little lone figures in a huge, heaving landscape.