I did not know the answer to that question until I had a fledgling end up in my yard this weekend. It was in the grass and flopping around, not able to fly. At first I thought it was injured but after some quick research on the web realized I had a fledgling on my hands. Some web information said it had probably fallen out of the purple martin house while other info said maybe it tried to fly out because of the high heat or was actually on the "porch" of my martin house and older adults martins tried to make it fly by knocking it off. No matter what the true reason was, I wanted to help it survive.
There's more to being a landlord for Purple Martins than just erecting a house. The first thing to do after getting that house for Christmas is deciding where in the world it should go. The yard is the obvious choice but where? Here's some tips I found when researching purple martin mania: