Cute pose. Some improvements would be to reduce noise in BG and eliminate the dust spot below the branch near the peeling bark. I would also consider toning down the tree trunks.
I would crop the right border so the tree exits the image at the top right corner. This gives a sweeping line for your eye to follow down the branch to where "Alvin" is sitting.
I would then crop the branch on the bottom to fit the image size. Of themselves the tree and branch are not important to show. But they border the image and add interest.