I like the BG and bird's pose. Perfect HA. Not much you could have done about the perch unless you set it up. In that case it is a bit big for the subject. I'd sharpen a touch more. Nice going. Thanks for sharing. :)
I agree that it could use a tad more USM, I would also suggest more saturaton and tad more contrast, but the image is VERY nice, pose, BG, light, and detail are very very nice.
Congratulations.
Wrens have such great personalities. Love the pose.....first thing I thought of was a "Captain Morgan" advertisement. The perch may be a tad large but I like how it has allowed the bird to pose.