Egg Shell Recipe
I am ashamed to call this a recipe. All cooking should be this easy. You purple martins however, will gobble these egg shells up as if they were feasting at a banquet.
Step one Rinse the eggs off to remove any bits of yolk or white.
Step two Place egg shells on a cookie sheet in a single layer, with the broken part pointing down.
Step three Place in an oven for 10 minutes at no higher than 275 degrees. Longer is OK, but not less.
Step four Remove and let cool then shells can be crumbled up and placed in an old empty coffee can or a tupperware type container and stored at room temp. Just punch a few small holes in the container so that there is some ventilation.
That's it! All done.
As long as the egg shells have been rinsed off well so there are no bits of egg on them, it will not attract any bugs in the house.
How To Offer Egg Shells
Egg shells should be offered on a platform feeder close to your housing but not so close that a predator such as a raccoon could use the feeder to get past any predator guard on your purple martin house. So at least 4 feet is good. Of course there are platform feeders made specifically for the purpose of offering egg shells and nesting materials to purple martins. These feeders keep the purple martins up off the ground and safe from cats and the added height also gives them a greater feeling of safety increasing the chances that they will use it.