Thanks Gary, Adi, Peter, Jason, Gary and Rick. I tend to not post these birds for some reason, although I take pictures of them every day I am home. I can't resist. 
Jason, yes, I have the full set of Kenko tubes and use them a lot, especially in my yard where the distance is assured for the day. I didn't use them today. The quality is just as good as the Bigma without the tubes though, and it keeps autofocus. Here are some shots with the 20mm tube behind the Bigma.
And I was going to ask you, which teleconverters are you using for those long distance shots? I have the Sigma 1.4 and 2x TC's, but have found the 2x gives barely acceptable image quality while the 1.4x is fine.