It looks to me that the heron was in focus. The eye looks pretty sharp to me. It might be just the limit of what this lens can do.
I may be wrong but I think this picture was overprocessed? Also, this picture background is so busy I'm surprised it turns out this well. I too have many like this and I would not keep any of them.
I was messing around with the original in Preview on my mac laptop pro and did change some coloring and tones etc and then I could not get back to the original so it could very well be overprocessed. I struggle with the af settings on the 70D and end up with out of fucous pics more often thn not. Thanks for your input, I appreciate it.