Summarize:

To protect a feeder that sticks to the window, cut a large circle or heart shape out of newspaper. Tape that inside your window for a pattern. Then, use your finger to draw a Vaseline barrier on the outside of the window. Place the feeder in the center. This method is best used in a cool, shady area. In warm weather the Vaseline will start to run/ drip. For a hanging feeder, cut a hole in the center of a lid to a tub of margarine or other small, lightweight object and string the hanging cord of the feeder through the hole. Make a knot in the cord, if necessary, to hold the lid in place. Smear petroleum jelly on the lid or other object. The ants may get to the lid, but they will not make it to the feeder, and other ants will not make the attempt. Wrap a band of ribbon flypaper on the feeder pole, or place on window or custom mounts. Flypaper has glue on both sides, so ants will not cross the paper. Keep the fly paper away from the feeder so that birds do not make contact. If flypaper comes off in high heat, hold it up with small pieces of duct tape that have no smooth surface exposed for ants to crawl on.
Use petroleum jelly. Make a petroleum jelly barrier for a hanging feeder. Use flypaper.