You got some nice pictures, very nice series. But once you enlarge and crop then it's obvious where's there's a little blur (which is how it can be if you're getting shots fast and trying to keep still enough, etc.).
Slow down and take your time to think about each picture individually. These are cropped down more than necessary and eliminates the interesting background that gives a frame of reference as to where the bear is and what it's doing.
I can see with each picture how I'd try cropping and for each one I see a different way to crop. There's an interesting pattern of branches that almost looks like a cross, I'd think about which pictures would I want to keep that in? which ones have less interesting background that might be better cropped down more?
I'm a film photographer (as well as digital) so I'm used to getting what I want in camera most of the time. But when I do crop, I often do a 1st crop that's fairly slight, save that, do a 2nd crop, save that, go back and look at them (sometimes come back later and look again) to decide which looks best.
Your pictures are good, don't chop the heck out of them! it's a matter of thinking about the amount of space around the subject, noticing the background, and thinking about the balance of the composition. You have something good here, take your time with it.