Barn Swallows in gourds?
Discovered some "forgotten" bird house gourds and researched turning them into birdhouses. Discovered that if we wanted bluebirds to nest the hole had to be exactly 1.5". OK, did that hung them in a maple tree and waited. 3 weeks later I was amazed to see a barnswallow trying to get into the hole, but it wouldn't fit. Going out to the barn I got a half round wood rasp and enlared the hole(s) and the barnswallow is not going in and out. Also observed a "territorial dispute" between two barnswallows and a blue bird over one of the gourds?
I'm confused by this, the barnswallows I'm familiar with nest in barns and make nests of mud, etc. They don't move into ready made nests, or do they? Or perhaps what I'm calling a barnswallow is another swallow?
Anyone else seen this?
Thanks for your time,