Hi Bill, I looked at your images and read the information you provided. I am not that familiar with Cannon cameras but I think yours has a crop factor of 1.6. Shooting at 500mm with a crop factor of 1.6 gives a full frame equivalent of 800mm. Looking at the birds in both originals they are very small, at that distance the feather detail is much too small for the sensor to resolve. In my opinion you need to be closer. When I shoot small birds with my 300mm (FFE 450mm) I am normally within 10 feet of the bird. In the image below I was within 10 feet of this bird. If you see a bird flitting around be patient, stay still and let the bird come to you. Decide where would provide a pleasing background and pre-focus on that limb and wait, let the bird come to it and be ready to get off a couple frames when it lands. It took a lot of images and time for me to learn to get closer, the feather detail has to be large enough for the sensor to resolve it. I shoot everything hand held, for my 300mm I use a minimum shutter speed of 1/400. A good way to determine the minimum shutter speed needed for a lens is to multiply the mm of the lens by the crop factor of the camera/sensor. Without a tripod I can respond quickly when a bird lands or if one flies by. For flying birds I use a minimum shutter speed of 1/1600 or faster if the bird is fast flying like a duck. Not conventional by some standards but I like to travel light and a tripod and large lens is just too heavy to carry for my liking. So I shoot what is within the range of my lens. Do I miss some oppurtunities... sure. Hoping this helps...
Straight out of the camera...