The fourth shot is by far my favorite. The fifth is a nice composition. All of these shots seem to be in challenging light conditions, and the kingfisher?? isn't sharp. But in that fourth shot, you've captured some intense direct light right on the bird's face, and it is striking. Nice job! Contrast that one to the black bird with the bright background, where the bird has little detail.
A better Beamer flash accessory can help eliminate harsh shadows in some challenging light situations.
http://www.amazon.com/X-Tender-Bette.../dp/B000SLNNG4
Did you have to crop in much?