Andrew Bird has such a charming singing voice that he could sing the dictionary and it would still sound good. In fact, sometimes his songs feel like he is singing a dictionary. I mean, how many other singers put 'mitosis' and 'osmosis' in a song? Although, if you are going to use 'mitosis' in a song, it does make rhyming sense to use 'osmosis' as well.
For some people, the brainy-ness of Andrew Bird is something they turn their noses up to (or at least, I remember a Paste review of Noble Beast that focused mostly on the book smarty-ness of his lyrics and seemed to miss the fact that the album was great), but I like it. This is mostly because the instrumentation and melodies are so lovely, but I also like how listening to Andrew Bird makes me feel a bit smarter. It is kind of like the audio equivalent of having one of those '1 New Word A Day' calendars, with whistling.
His latest album is his most 'lyrically personal' album, although there are still big words and weighty topics to be had. But most importantly, the songs are all really ace. The melodies are there, the looping violin riffs are there, and the expert whistling is there. It's all there, and it is all great (and you should get it).