The Roamwild PestOff Deer/Starling Proof Cage Accessory stops starlings and deer feeding from your PestOff bird feeder. The cage clips on in seconds and comes off just as fast; its openings are sized so songbirds pass through while starlings, grackles and deer are kept out. $22.99 with free US shipping. Feeder sold separately.
PestOff ports close under the weight of a squirrel or large bird, but a European starling weighs only about 2 to 3.6 oz, close to the port threshold, so starlings can sometimes feed. In the United States the European starling is an introduced species and is not protected under the Migratory Bird Treaty Act. The cage adds a physical barrier that ends the problem. Feeding sunflower hearts instead of mixes with suet or dried mealworms also makes the feeder far less attractive to starlings.
Problem Solved.