Studying the walk cycle and animal movement

To create a realistic animation the most important part is accurate movement and tweens. The modeling can be fairly simple with a well done animation as the story is told by the activities the characters do, not the quality of the rendering. With this in mind I have been looking into walk cycles and motions which the human body use for certain activities. I have been using a mirror alot too for my modeling to get an accurate idea of motion in the limbs. I am trying to gather some clips of snakes and birds movements, to study and learn about their form in motion.