The crop is definitely an improvement. Before, it was a picture of the ground with a squirrel, now it's a picture of a squirrel. You might be able to go even tighter.
Another composition tip. The image would have been even better if you could have gotten lower to the ground. Everyone's looked down at a squirrel. It's much rarer to look at them at eye-level. Of course, he was probably on the move here, so that may have been difficult.