Most things are already mentioned below but I think the bird itself looks quite good. Nice curious pose and eye contact. The time of day and a close background was your main issues here.
Yes, I agree with he folks above, plus i wish the top left part of the BG was more textured - it just abruptly becomes smooth directly behind the bird's head. Sharp, and a great look at the eye. My favorite sparrow species - always a joy to see!!