I hated to do it but I picked up pole and laid it down and pulled out two huge nests with eggs in both and cleaned it out and set it back up and will continue to monitor and keep clean till I see some PM scouts show up.If you want to attract Purple Martins, you have to get their house cleaned out and keep it clean and unoccupied very early in the spring when the scouts and juvenile males start looking for a place to start their colony. If the house is full of sparrows or starlings or whatever, they won't stay. It is a pain in the ass to do as you probably have to go clean it out every other dang day. We had Martins come and inspect the house many times, but none ever stayed. We gave up on the Martins, but we have Tree swallows that moved into the Martin house 10 or 15 years ago, and they have come every year since. They are nice birds to watch, too, and often live with or near Martin colonies. Nancy and I have sniped dozens of sparrows and starlings off of the hanger that the gourd houses hang on to help out the Tree swallows over the years.
Ron had two pairs of PM fly into his house as soon as he and a neighbor put his up and a day later had 6-7 pairs move in but he’s had them for a few years.
These barn sparrows or wrens move in as soon as I put mine up. I did the same thing last year but they won’t take the hint