Eier sind wegen ihres hohen Nährwerts eine begehrte Nahrung. Als Reaktion haben sich zahlreiche Strategien zum Schutz des Eis und somit zur Verbesserung der Überlebensfähigkeit der jeweiligen Art entwickelt.
Bird eggs have been valuable foodstuff since prehistory, in both hunting societies and more recent cultures where birds were domesticated. Eggs are a common food and one of the most versatile ingredients used in cooking. They are important in many branches of the modern food industry. The most commonly used bird eggs are those from the chicken. Duck and goose eggs, and smaller eggs such as quail eggs are occasionally used as a gourmet ingredient, as are the largest bird eggs, from ostriches.
