Put up a Martin house properly and they will find it. They return every year to the same location. I had a Martin house that housed 12 pair plus all the babies and never saw another wasp or yellow jacket. They are cool song birds and bug catching matchines.Where do ya get a colony of Purple Martins?
Here
https://www.purplemartin.org/resear...EgFvOSrme66pIwCDdPicrEgOsbWqeKIsaAioEEALw_wcB