Bird eggs are sought after as a source of nutrition by humans and other animals. Each of the Bird eggs is large reproductive cell enclosed in a shell made out of calcium salts derived from the skeleton of the female bird, therefore for the females to keep laying strong eggs she needs to feed well.

Bird eggs are laid by the female but are incubated by both the parents in most cases. The eggs are laid in groups and each of them is known as a clutch of eggs. A single bird hatches out of each egg.

The clutch of eggs may have one to as many as 18 eggs laid by a condor and partridge respectively. Larger the bird larger the egg and vice versa therefore the Ostrich lays the largest egg while the vervain humming bird of Jamaica lays the smallest egg. The shapes of the eggs too might vary, this happens due to the process by which they are created.

Most eggs are rounded at one end and slightly stretched and pointed at the other this is due to the process of their creation when they are being forced out of the oviduct. The muscles in the oviduct squeeze and push the egg forward therefore it becomes more rounded at one end while its back remains stretched behind. The Bird eggs of the cliff nesting avians are slightly conical this prevents them from rolling off the cliffs instead they roll in a tight circle. This shape of their eggs has developed via natural selection similarly the eggs of the birds dwelling in nests are spherical.