What Is in Bird Food?

Birdseed

• Be careful when buying commercial birdseed. Mixes are often heavily weighted with filler seeds like red milo that birds don't eat. What birds do love are black-oil sunflower seeds. These are very meaty seeds with thin shells that are easy for cardinals, chickadees, finches, and sparrows to crack. Big, striped sunflower seeds have thick shells that require strong beaks like your pet parrot's, and may be too hard for smaller birds to crack. Thistle seed attracts finches and safflower seed will lure cardinals, but they really prefer black-oil sunflower seeds. Cracked corn and millet make sparrows happy. Quail and doves will also eat cracked corn.

Suet

• Suet is beef kidney fat and will attract insect-eaters like small bushtits, nuthatches, wrens, warblers and bluebirds as well as some woodpeckers. It comes in processed cakes that contain berries and seeds. Suet will go rancid in the heat so replace it often in summer. You can buy plain suet at the butcher's for an economical backyard feeder.

Grit and Calcium

• Birds need calcium for egg-laying and grit to grind food in their gizzards. Cleaned, ground oyster and egg shells are part of a healthy diet for birds. If you add egg shells from the kitchen, boil them to sterilize them and then smash the shells into pieces as small as sunflower seeds. Serve the grit course in a feeder next to the seeds.

Nectar

• Hummingbirds are tiny sugar fiends. They need a constant quick source of energy to fuel their powerful hovering and flight and your hummingbird feeder will be well-attended if you reliably provide fresh nectar. Make sugar-water nectar by adding four parts boiling water to one part sugar. Stir and refrigerate after it cools. Serve the nectar in a feeder hung where the birds can perch or safely hover away from predators. Change it often -- every three to five days at least -- to prevent fermentation that will kill the hummingbirds. Orioles may also be attracted to your hummingbird feeder, although they prefer a slightly less sweet mix.