I was parked in an area at the Sequoyah National Wildlife Refuge in Oklahoma watching and photographing a Great Blue Heron standing on a submerged log. The Heron was standing very still until it saw movement in the water nearby. It started leaning forward on the log it was on and the log moved. The Heron was having a problem keeping its balance and the more it tried the more the log would move. The log began rolling and the Great Blue Heron couldn't get it under control. I switched my camera over to video mode and was able to get the struggle the bird was having staying on the log. As you can see in the video the Great Blue Heron did a great log roll before giving up.
Great Blue Heron Log Roll - Sequoyah National Wildlife Refuge - Oklahoma