Aww, lovely to see. Looks like a male, possibly a juvenile as its beak is quite short but without seeing the feet and legs, I can't be sure. The feet and legs of juveniles are a dark, browny orange, rather than the vivid orange of adults. Juveniles have a white tip to the beak also but I can't see that on this one, so could just as easily be an adult.
When you crop or zoom in, images often fall apart as any missed focus, noise grain etc will be highlighted. You get to a point where you start seeing the pixels with extreme crops/zooms.
I think it's a combination here, it's slighly soft to begin with, at the shutter speed used, which is relatively slow, it could be movement of the perch, the camera or even wind moving the perch and bird on it. Also, any breeze would ruffle the feathers and make them appear soft. The light hasn't helped as that will obviously affect shutter speed but the right light will also bring out the detail on the Kingfisher and make things easier all round. We can't control the light in situations like this though, so I would suggest bumping the ISO a little, I'm not familiar with the ISO performance of your camera but 450 is quite low, I'm sure if you expose the image well, you could get up to 1600 at least, quite comfortably, which would increase your shutter speed. Some quick math ( I may be way off), ISO 1600 would have given something around 1000/sec, in that moment, which is getting there. Exposing well and to the right of the histogram will cut down on noise at higher ISOs. Watch the whites though, they are a bit of a nemesis for me with Kingfishers and have tripped me up many a time.
If you want a frame filler though, you will need a longer lens and to get closer to the bird and even then, still be prepared to crop to an extent. Cropping/zooming is fine but it can't compete with getting closer to your subject. I'm guessing your Kingfisher is about 30 ish feet away?
I shoot Kingfishers regularly at 600mm on full frame and a crop sensor camera too. I have them perching about 15 feet from my camera now. Even at this distance, they don't fill the frame. I like them close and especially with the 5D, I find myself cropping by about 30-40%. I really have to nail the focus and exposure, even at that distance. The 5D though gives excellent detail and stands up to cropping well, but I still have to produce a decent file. My crop sensor performs well too, a Canon M5 but I have to be even more careful with the exposure on that, being a crop sensor.
All this said, it's nice sometimes just to literally step back and get an image, like yours above with the Kingfisher in its environment.
Well done on your first one, it's not easy. I wish you luck with future ones but be warned, they are addictive.
_DSC1107 by John, on Flickr
