Jim, I must say you're doing great with the FF shots. Your position is obviously working very nicely for you.
I like the comp a lot here and the famous Nuthatch pose is always enjoyable.
Only thing I can offer is maybe a very slight boost in sat or maybe just a touch more in the mids on a levels adjust. Could even try adding a tiny bit of blacks in the neutrals. Hard to say without playing with it from here.
Jim I think the nuthatch is spot on I love the russet colouration of the feathers, but I would suggest masking it and lowering the brightness of the background just a little (I just made a selection >Curve and pulled the mid point down slightly).
Really classic look on this nuthatch! Looks excellent, but I would increase the sat a bit mostly on the BG or a slight or bring up the midtones a touch.