Pannage is an English legal term for the practice of turning out domestic pigs in a wood or forest, in order that they may feed on such things as fallen acorns or beechmast. Today Pannage is observed in the New Forest national park of Southern England, where it is also known as "Common of Mast". It is still an important part of the forest ecology. Pigs can eat acorns and beechmast without a problem, whereas to ponies these foods are poisonous. The minimum duration of the Pannage season is 60 days, but the start date varies according to the weather - and when the acorns fall. The Court of Verderers decides when Pannage will start each year. At other times the pigs must be taken in and kept on the owner's land, with the exception that breeding sows (known as "privileged sows") are by custom allowed out, providing that they return to the owner's holding at night and are not a nuisance.