We added a hatch opening in the back. cut a space out big enough for fingers or hand then re fit with what you cutout
.we used little pieces of leather but you could use whatever to make hinges..glue hinges. Ours stayed closed but peice of heavy outside tape would work for both closings. Added small drain holes in bottom. Ours looks grayish weathered guess needs resealing .

 

For wild birds it would probably fit better in "the great outdoors". That's where I post all my wildlife threads.

I've never had anything nest in my birdhouse gourds.

I saw a neat way of setting up the gourds for Carolina Wrens in a magazine article. You cut off the top and hang the gourd so it's on the side. Those wrens prefer a long tunnel-like entrance according to the article.