Île des Pingouins eroded by the sea, steep-sided, 4 km long and 1 km wide. Its surrounding coastal cliffs vary from 50 m to 300 m in height, making it virtually inaccessible by sea and rarely visited. It is free of introduced species, so has a relatively pristine biota compared with the other islands in the archipelago. At least 29 bird species breed on the island, which has been identified by BirdLife International as an Important Bird Area (IBA). It has an exceptionally high density of seabirds, including a million pairs of macaroni penguins, 300 pairs of black-browed albatrosses, four pairs of Salvin's
Bird egg the shell immediately before laying, but this research shows coloration is an integral part of the development of the shell, with the same protein responsible for depositing calcium carbonate, or protoporphyrins when there is a lack of that mineral. In species such as the common guillemot, which nest in large groups, each female's eggs have very different markings, making it easier for females to identify their own eggs on the crowded cliff ledges on which they breed. Bird eggshells are diverse. For example: Tiny pores in a bird eggshell allow the embryo to breathe. The domestic hen's egg has around