Nice find, well exposed for the contrasty plumage and light you had. Tough setting, not much you could do and I'm sure you manoevred to the best angle. Looks like highly sharpened big crop to my eyes.
You must have been elated to discover and photograph this nesting BNS. I understand you didn't have a shot at him from a lower position and this angle really works fairly well. However, as Daniel mentioned, there are issues. Not sure about the size of your crop but your bird looks quite oversharpened and the light angle wasn't your friend. Good luck photographing them when the chicks are born. They are just beginning to hatch in FL.
Thanks, folks. Guess I'll back-off on the sharpening (I usually get comments that I don't do enough). No, Daniel, there's not much crop here -- just a bit off the edges for composition's sake. Marina, I'm looking forward to the little ones -- I missed them last year. I went out yesterday looking for the avocet chicks (which aren't around yet), but found this young lady instead. I have a few from a low angle, but they don't work at all -- just too many weeds get in the way of the bird.