As though quite unsorry to burst in on the star and the half-mortal boy's awkward fun, the shadow becomes a whole lot more solid as something swoops into the trees, rustling leaves, snapping branches and screeching in a high tone.

There are tawny brown feathers, Tristran distinctly notices (once he's past the fact that he can practically kiss the star right now), and other unmistakable birdlike qualities about this very, very large creature. And if they don't find some place to hide fast, they'll be spotted.

He pulls her towards the trees and forces Yvaine down to the leaf-covered ground quickly, just as the bird swoops through again -- all by instinct, really -- and manages to be ... well, quite on top of her at that point.