Before this movie came out, I read some people online ridiculing the fact that it had owls as the main characters, as though owls are the least badass creatures one could come up with.
Three things. First, these people clearly haven't read the books based on this movie. We have owls tearing off the faces and slashing open the throats of other owls. We have owls beheading each other and slicing off each others' wings. We have owls getting shoved into fires and and getting their vertebrae severed in two. We have owls getting their hearts torn out of their bodies. Secondly, there's another fictional work (which was also made into an even more infamous movie adaptation) that's probably the epitome of What Do You Mean It's Not For Kids and features rabbits of all things. And these aren't even rabbits that have superpowers or use weapons. Just normal rabbits. Although real rabbits can be quite tough at times, you don't get much more harmless than a rabbit when it comes to public perception.
Mild spoilers ahead.
For the uninitiated, the book series that this movie is based on is essentially about World War II, but with owls. The movie is allegedly based on the first three books, and it deviates from them... quite a lot. However, it does keep the central plot points of each book (being captured and escaping from St. Aegolious, journeying to and settling down at the Great Ga'Hoole Tree, and rescuing Ezylryb, respectively). I was mildly surprised by the fact that I didn't mind the major deviations from the books so much, because I usually do.
One of the strange things about the movie is that the owls are from all over the place, but some of the other wildlife are distinctively Australian. This is not something from the books, which appear to take place in a fantasy land populated not only by owls from all over the world, but also things like bald eagles, polar bears, puffins, flying snakes, and even dire wolves. Somehow, I suspect that the author just threw in whatever species she thought were cool.
On the owls themselves in this film, I thought they were quite well done. They move like real owls, look like real owls, and, although I'm not familiar with bird calls, they reportedly even sound like real owls. Furthermore, no Feather Fingers in this movie at all! The one glaring error I picked up was that the female owls were noticeably smaller than their male counterparts, when it is usually the other way around in real life. (The presence of this inaccuracy is particularly strange, because this is something the books got right.)