Macaroni penguin of the body, and head and neck hunched, and general hunching of head and neck when incubating or standing at the nest. The macaroni penguin's predators consist of birds and aquatic mammals. The leopard seal ("Hydrurga leptonyx"), Antarctic fur seal ("Arctocephalus gazella"), Subantarctic fur seal ("A. tropicalis"), and killer whale ("Orcinus orca") hunt adult macaroni penguins in the water. Macaroni colonies suffer comparatively low rates of predation if undisturbed; predators generally only take eggs and chicks that have been left unattended or abandoned. Skua species, the snowy sheathbill "(Chionis alba"), and kelp gull ("Larus dominicanus") prey on eggs, and skuas
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