If you are a member of the PMA, you know there is a lot involved. I enjoy experimenting with my little newly formed family of Martins, (if they return this year)but I do not get that involved with the organization. The birds do fascinate me, and I love to learn more and more about them and their habits, but it is a job, recording and documenting all the required stats when you are really into it.
The Purple Martin Association has a catalog that I get each year. In it, they have a new shape of entry hole which can be used on our bird housing.It has a specific shape,and is designed to fit the bone structure of the Martin as they enter the housing, but not the larger birds that may try to enter. It can be placed over the existing opening of older housing.I have not converted the opening to my housing yet.I may decide to do that after awhile,if I see the other birds are giving the Martins a problem.Pop says the Martins are pretty aggressive when it comes to protecting their territory,and I did see a bit of that played out this last summer.
For houses that have the larger compartments, a starling-resistant entrance hole is strongly recommended. These new holes (SREH's) have been tested since the early 1990's and are proving to be an asset in allowing martins a safe nesting place that is not accessible to starlings. (This paragraph was copied from the PMCA information page)
I found this pattern in the PMA catalog regarding the latest shape for the entrance hole.
My birds have not returned as of yet, and there is no certainty that they will,but I am hoping they will.I have put up a few extra houses,and replaced a couple that were in bad repair. I had a small pond dug,close to their housing,although it still needs some work.Hopefully, they will show up soon.If not,I'll keep trying to lure them back once more.I do enjoy watching them.