When I had 100 pair purple martin colony. I would cover pole up with 5 foot PVC pipe, Vaseline it up so snakes could climb the metal pole. To add third security measure I added bird netting at top of PVC pipe. PCV pipe works, but it works much better the Vaseline, bird netting, and prevented ants from climbing also. If snake makes it to nest chamber it will clear out all the compartment one by one. IMO I always said Purple Martins are hard to get and twice as hard to keep colony’s going year after year.

Wait until the squirrels find their way into your attic! You don't have problems until they return year after year to have babies and the babies have babies! I will do whatever I have to do to keep my investment safe and rodent free! People that feed birds are contributing to the increase in rodent population.. I will continue to purchase and release snakes in my neighborhood...