I'm gonna take a guess and say: Heavy Oboe (for Radagasts' absent-mindedness), and plenty of whimsical flute and recorder overtones (Pan-style) for his feathered friends, and let's not forget the deep pizzicato on the cello and violins to back up the over-all silliness of the character.
This will be more comical than the previous Jackson outing. Don't get me wrong, I'm gonna eat it up! Just wish there was a more dire feel to the whole thing. As soon as I saw Gollum without his glowing pale green eyes in a trailer I kind of lost hope that we would see the "Riddles in the Dark" scenes play out in the truly terrifying and dangerous manner in which it was written. Instead we will see "Riddles in the Dork"
Riddles in the Dork? Lol Like the idiotic movie they made about Star Wars way back when? With this short Lord Vader, who had an identity problem? Where they gave them all those dorky names?
__________________
Hey dol! merry dol! ring a dong dillo! Ring a dong! hop along! fal lal the willow! Tom Bom, Jolly Tom, Tom Bombadillo!