Grey petrel

The grey petrel (Procellaria cinerea), also called the gray petrel, brown petrel, pediunker or grey shearwater, is a species of seabird in the Procellariidae, or petrel family. It is pelagic and occurs in the open seas of the Southern Hemisphere, mainly between 32°S and 58°S.

The grey petrel is a large grey, white, and brown petrel. It averages 50 cm (20 in) in length, 115–130 cm (45–51 in) in wingspan and weighs around 1,000 g (35 oz). It has a brownish-grey mantle, back, uppertail coverts, and upperwings. The belly is white and the underwings and under-tail that are ash-grey. It has a yellow-green bill and pink-grey feet.

As a member of the Procellariiformes, it shares that order's identifying features. First, these birds have nasal passages called naricorns that attach to the upper bill. The bills of Procellariiformes are also unique in that they are split into between seven and nine horny plates. The birds produce a stomach oil made up of wax esters and triglycerides that is stored in the proventriculus. This can be sprayed out of their mouths as a defence against predators and as an energy-rich food source for chicks and for the adults during their long flights. Finally, they also have a salt gland that is situated above the nasal passage and helps desalinate their bodies, due to the high amount of ocean water that they imbibe. It excretes a high-salinity solution from the nose.