Calcium is crucial for egg production

Eggs of a female Northern Cardinal

Calcium is an essential element in the diet of birds, especially for producing eggs, or more specifically, for shell production. Without enough calcium, eggshells can become defective and the hatchlings never hatch, or young birds may develop deformities of their beaks.

Female birds must change their diets during the nesting season to obtain calcium-rich nutrients. Seeds and insects alone are not enough, as they provide only 10 percent of the calcium needed for egg laying.

Backyard songbirds do not "store" extra calcium in their skeletons. It probably would make them too heavy to fly well or escape predation. Egg production is in stages. Fat and protein are deposited in the egg within the female's body over a four-day period. Eight hours prior to laying the eggs, 60 percent of the calcium is deposited in the shell. So where do female birds get the calcium in that narrow window of time?

Millipedes, worms and woodlice are ground dwellers and are part of bird diets. The insects don't provide all the necessary calcium but the soil in the insects' gut does. Snail shells also provide plenty of calcium. So does sand, dirt and ash. Some birds get calcium from bones of carrion or shed deer antlers. They will even consume shells of spent eggs from their own broods.

Historically, calcium carbonate is harvested from the soil's surface by birds. However, air pollution and the resulting acid rain can dissolve any calcium carbonate on the soil surface.

Calcium suet benefits egg production and young birds' bones

We can help by using egg shells from your kitchen as a supplement for birds. Wash out the empty shell and bake at 250 degrees for a half hour. This will prevent salmonella contamination of the bird feed. Crush the shells between your hands into small pieces. Mix these pieces into the bird seed. This provides a needed nutrient. It also may attract a greater variety of birds to your yard.

Also, you can provide "Calcium Delight," which is available at The Bird House. The product is a no-melt suet dough that comes in standard-sized suet cakes. In addition to calcium, other ingredients include roasted peanuts, corn, rendered beef suet, oats and soy oil—which together provide plenty of fat and protein. The ingredients are especially helpful for fledglings and young birds. They need the calcium to strengthen their bones. The fat and protein help them develop so they are ready for long-distance migration in the fall.

Take these steps and the end result will be more successful broods and greater joy as we watch the antics of young birds.