I finally saw The Hobbit, despite my earlier difficulties. One thing that stood out to me was the use of CGI songbirds, particularly in association with the wizard Radagast the Brown (who, I found out in researching this post, is also the seventh Doctor Who). I thought that I would share some ideas on the identification of these birds, although in all likelihood someone somewhere else has probably done a better job of this already.
The birds that live under Radagast's hat looked like House Sparrows (Passer domesticus). I also seem to remember that they were both males, but I'd have to watch the movie again to be sure.
The bird that alerts Radagast to the location of the Necromancer is very clearly an American Robin (Turdus migratorius). I found it somewhat disconcerting to see such a characteristically North American bird in the setting of pseudo-European Middle Earth.
And the bird identified as a thrush that flies to the lair of Smaug at the end of the movie actually is a thrush, though I couldn't identify the exact species.
Radagast the Brown's talent for communicating with birds was acknowledged in the world of paleontology in 2002, when his name was applied to Paraortygoides radagasti, a fossil bird from the Eocene.