Birds prepare their eggs for the worst, whether the risk comes from predators or just the location of their nests.
Fork-tailed Storm-petrel (Oceanodroma furcata):
This Alaskan bird’s eggs must survive on their own for long stretches in cold weather, while their parents fly long distances scouting for food. Impressively, most of the eggs survive. They have a high tolerance for cold, and can also delay their hatching if the parents are away a lot.
Read about some more incredible eggs over at BBC Earth.
Photo credit: Kevin Schafer/NPL, Sue Flood/NPL (thumbnail)