It is easy to get started feeding birds, but novice backyard birders often make simple mistakes that can keep birds from enjoying the feeders. While some mistakes only make feeders unattractive, others can endanger the birds. Feeding the birds requires more than just putting out birdseed, and avoiding these top 10 bird feeding mistakes can ensure a healthy, nutritious backyard buffet for a wide range of bird species. Birds “chew” their food in the muscular part of their stomach, the gizzard. To aid in the grinding, birds swallow small, hard materials such as sand, small pebbles, ground eggshells, and ground oyster shells. Grit, therefore, attracts many birds as a food supplement or even by itself. Oyster and egg shells have the added benefit of being a good source of calcium, something birds need during egg laying. If you decide to provide eggshells, be sure to sterilise them first. You can boil them for 10 minutes or heat them in an oven (20 minutes at 250 degrees). Let the eggshells cool; then crush them into pieces about the size of sunflower seeds. Offer the eggshell in a dish or low platform feeder.