I saw the movie last night (pre-screening). It was quite funny. The humour is not really making fun of birders, really, more just silly situations. This movie is aimed at the mass market, so birders' in-jokes are largely avoided. There is a fair bit of overdone life-lesson sentimentality that is mostly nowhere close to subtle. The birding is really not very realistic at all, but this is a comedy, not a documentary. I did not like how the characters were shown running around and whipping binocs from side to side. And a lot of the birds were digital effects, so you really have to suspend disbelief. While this story has some basis in truth, they have fictionalized a lot of it, so that what you see here in many cases is completely made up for entertainment value. They went to a lot of places to film. mainly in BC and the Yukon, but captions on the screen identified these as various US locations. In one coastal scene that was supposed to be Monterey, CA, I saw a standard Parks Canada brown and yellow sign, so I think that was probably Pacific Rim NP in BC. It was well acted. The supporting cast is quite strong in addition to the main 3. Owen Wilson really has the best part, I thought, which he does very well. Jack Black is less manic overall than the trailers would lead you to expect. Steve Martin has the least to do, and is mostly the straight man.
Overall, funny and not really a tone of mocking birding, but the birding in it is unrealistic. Like the book, it is about obsession and what you sacrifice both in pursuing or not pursuing dreams. 2 1/2 stars. Maybe 3 if I'm generous.