The pear-shaped eggs of a common murre (Uria aalge) can sport a blue hue, be speckled or feature brown streaks. Oh, but that egg-inside-an-egg story that made the rounds around the internet?

Zimbabwe‘s weaver birds lay their eggs in communal nests, while the shape of common murre eggs prevents them from rolling down steep slopes. Ostrich eggs are white to reflect the sun‘s heat – but this ...