I installed 1 1/2 inch ports to keep the starlings from getting inside. Also had to tape over the plexiglass openings on the side. I'll be replacing the plexiglass with solid sheets at some point. I've disassembled this bird feeder and it's nicely made. The screws are not stainless, so I will watch them to make sure they don't rust. The starlings can still poke their heads in and eat the mealworms close to the opening, but they cannot reach the middle part, so that is left to bluebirds. I plan to put a small cup in the middle to keep the mealworms away from the openings. Good feeder if you can keep the larger birds out.