Save your eggshells and offer them to the birds. Female birds need calcium—especially during egg-laying season. When cooking, save the empty, rinsed-out egg shells in the refrigerator in a jar or plastic container. After you've accumulated a dozen or so, bake them on a cookie sheet at 350 degrees for half an hour to kill any residual bacteria. When the shells have cooled, crush them into small bits and offer them to the birds on a platform feeder; toss them on a roof; or scatter them on a deck railing or sidewalk.