With the Hounds being some distance from him still, he will hold his action but keep his eyes peeled, especially in the other direction for the rest of this little party to show themselves. He will stay as still as possible to avoid drawing attention to himself.
As soon as Gnurl, with Featherwind's help, detects the approaching foes, (I'm thinking that an owl will see and hear them coming pretty far out?) he will ready a spell.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.