Tennessee Wood Pecker

I don't know what to tell you, Brian.  I am certainly not a pro by any means, but will make a stab at it. First of all, I like his pose, and the leading line of the limb.  I like that you got the back of him, with a side profile of his head.  You are right, the light is a bit harsh, and I am sure that is affecting the colors.  I am thinking maybe if you desaturate a little, it might help.  I was hoping to look at a larger version, but when I pulled it up, it appears to be the same size, so I can't see how well the detail shows up, etc. I would suggest also that maybe if you can, put your subject a bit off center (rule of thirds I think would work nicely on this shot).  I love woodpeckers, but they are the hardest for me to get a good shot of, because they do just what you said, move around so that his is either in bright sun, or shade.  Maybe, if this is a tree that he frequents, and is where you can return to, you can catch him on a cloudy day, or sweet light in the morning or late afternoon, but cloudy would probably be best to avoid a lot of contrast between sunlight and shadows.  I hope that helps. 

I think Shirley gave you some good advice.  The only thing I would add is that you probably could have benefited from slightly higher iso and a faster shutter speed.  Because you did not post a larger image I cannot judge the detail accurately but from what I see, it looks pretty good.

You should talk to a Canon owner who has the same model as you to find out what is the limit with respect to noise issues on iso for this camera.  I think that will help you in your decision-making process.  While it is easy to handhold the Sigma lens, you will always get a sharper image with a tripod.  You are going to have some issues at 1/250 of a second if you are handholding this lens at 600 mm.  It is also considerably sharper at 550 mm if you are shooting wide open.

The main issue would be the harsh light.  But as we know we can't always tell the birds when to come.  That said, I think this image has potential in postprocessing.

Nice image Brian, sharpness looks good.  To my eye it looks a little bit on the yellow and oversaturated side so perhaps lowering the white balance a little would help.  A small crop from the right and top would move the woodpecker out of the center.  If you have more space on the left you might include it as well.  All that said, I think it's a good effort considering the situation. 

Is this a local name for a red-bellied woodpecker?  I would agree with decreasing the yellow, as, at least in the books I looked at, the face isn't this yellow.  You might crop this so there is more room in front of the bird than behind it.  You might also try decreasing the background highlights and increasing the shadow detail around the bird.  I like the pose with the slight head turn and the angled perch.

I'm still not sure why you're not getting the larger image, Brian.  From what you sent me off-line, it seems as if you should.  At this scale the detail looks pretty good.  The light is pretty intense throughout the image with lots of competing primary colors, but there isn't much you can do in that situation.  I think this would work better cropped to a vertical format and eliminating the in-focus bright leaves entering the middle of the frame on the right.