A lot of good advice has been given in the previous posts. However, my experience in shooting birds tells me that the biggest problem you experienced with this shot was the lighting. Strong Winter sunshine, with the sun in its low equinox, is just not conducive to good photography, specially when shooting a fast moving, unpredictable subject such as this Robin.
Also, given the fact that birds, such as Robins are renown for always being on the move, with their continual bobbing, a great deal of thought needs to go into the camera settings before taking the shot.
Let's firstly deal with the light. Strong Winter sunlight will always give a harsh, contrasty image. The camera needs to be set so there is at least -.5 exposure compensation. The shutter speed needs to be 500th sec minimum
. The F-stop has to be set at 5.6 minimum
as a starting point. ISO set at a starting point of 200.
Before you actually start shooting the birds, take some time to take some tester shots to get the exposure right and alter the balance of the settings for each focal length, remembering its changing f-stop, to get a good exposure. I would recommend spot metering and use of the AE lock. Keep increasing the ISO, again remembering that this is the equivalent of one stop from 200 to 400; ISO 360, for example will be the equivalent to 1/2 a stop.
Keep balancing the exposure compensation to get the best exposure possible. Repeat this for faster shutter speeds. If you want to capture birds in flight, specially this size bird, a shutter speed of 2000th sec minimum will be required to freeze the movement of the wings.
Lastly, practice your panning techniques. Personally, I never use a tripod unless I am shooting at extreme range - they are just too cumbersome to capture fast moving songbirds.
One thing to understand is that slightly underexposed images can be recovered during post processing, blown images are lost forever.
Regarding your photo. I cannot for the life of me understand why the log should be blurred when the bird is sharp, as certainly the blurring is down to camera shake. I have taken your photo and done a modification on it regarding cropping. I have given an example of cropping to the Golden Ratio, removing the blurred log and still giving balance to the image.
Hope this helps.