Here is something I am going to try this year to try and frustrate snake attacks. Place a squirrel baffle about 4 feet up the pole. Then tie or tape a layer of clear plastic with a "skirt" of plastic hanging down all around. Then place a second baffle over the first one to help secure the plastic and provide a hard to climb upper surface. I am hoping the plastic will make it hard for a snake to get up and over the baffles.
A second thing I am going to do is face more of my gourds toward the pole. Last year I had 3 gourds on a three arm perch. I placed one facing the pole. That was the only one of the three used. The gourd had a round hole. The hole was positioned about 10 inches from the round, 1 1/2 inch (outside diameter) pole. I feel that the pair felt safer, and maybe in fact were safer. They had to do a little extra maneuver to enter the hole. Maybe a porch would help there.
My site and my available time lends itself well to my starling and sparrow stalking technique. Made it easy to keep those invaders at bay.