Classic nuthatch pose. Well exposed, pleasant BG. To my eye, just on the edge of being oversharpened, as I am starting to see some fine jaggies in the light straight lines of feathers.
Nice feather detail, comp, exposure and perch. Doesn't strike me as oversharpened, but I don't user a jeweller's loupe (or digital zoom equivalent) when looking at images, and may miss things like this.