Welcome, Marcel. Nice video Marcel! I have never had 13 bluebirds at once!! The most I’ve had is maybe 6, the siblings and parents from the last nesting. You can try a sparrow spooker on your house. It helps most of the time with discouraging house sparrows. Is your acorn nestbox easy to monitor? (an access door to look in on things?)We just switched forums here so it will take awhile for everyone to find this and even then our numbers are a little low here recently. But usually there’s plenty of activity during nesting season. Something else you might want to have on hand is a Van Ert trap. It’s a trap you put inside a nestbox. When you have a HOSP claiming a box you can trap it with this trap. I’m not sure if it would work with your Acorn box. Is the Acorn Box a decorative box? I’m a little worried about it.
Tammy