Let me set up the shot first.
1. The sun was at about 35-45 degrees over my left shoulder.
This is a camera exposure ( metering ) disaster ready to happen. The bird goes from white to black. It would be impossible for me to let the camera set exposure on this shot. The bird is moving and I use center point metering and AF. At this point in my birding I only shoot Manual mode.
First you want the bill to be properly exposed, but the darker colors are better with a longer exposure in most cases.
You must know your camera sensor characteristics. The Canon 7D is a tough camera to shoot.
First I spot metered on the white. Then set it -1 in the graph. DSLR's make this easy. It is mostly a proportional graph. Straight line really. If you see it two tick marks above 0 then compensation can be make with two clicks in opposite direction. With shutter speed, F stop or ISO.
Also make sure your highlight clipping is on in your DSLR for a quick look if needed. I find that a good method if I have the time. Many times the bird is gone before you have time to stop look down and re-adj.
So the bottom line is to get the bill exposed properly and pull your dark areas back in Post processing.
My opinion, and how I shoot & process a shot like this.