Nice with some snakes... I think it is the first time I have seen a snake being photographed with a 600mm... And even if I like the colors I prefer to see these arboreal vipers in the trees...
wow Awesome Phil, the red strip on the viper looks great. Good job on the DOF and exposure. And you did not clip the tail!
Its easy for me to say now since I was not there, but if you could have taken a step to the right the small OOF leaf would have not have been so close, its not a big problem as is, but the step would have made it better if you would have noticed it in the field.