I wish you had a slightly better head angle. However, from what you say, these guys may be a little jumpy. It is sharp where it has to be as mentioned. What a lovely bird!
One key thing you didn't mention is what was your shutter speed.
I've mostly used a 1DMkIII for the last two and a half years and will not hesitate to shoot even ISO 3200. However, at that ISO NR is usually a requirement, I think I can get away without it with good exposure (to the right with histogram) technique without any NR usually at ISO 1600, unless I have many many very dark tones.
Here is a sample from my 1DMkIII using ISO 1600 cropped to 100% and I am happy, but I am not as anal as a lot of folks and can accept this. WDYT?
http://amatteroflight.com/gallery2/d...rcent-crop.jpg