I built my sunflower feeder support mast from 1 1/2 inch Schedule 40 plastic pipe. I figured the plastic finish would be too slick and hard for squirrel claws to grab.
This guy solved the problem - he simply 'hugged' his way to the top.
I've no idea if he would have 'slid' down the 1/16 inch steel cable to the pan holding sunflower seeds because I think he noticed me taking the picture and fled the scene. Scrambled down the pole barely under control. So funny.