Badgers use a variety of materials as bedding, depending on the time of year.
Most commonly used is dry grass, leaves, bracken, hay, straw and moss. They use also Bluebells and other green material during the Spring, which as it decays produces heat which can help keep the cubs warm. Garlic leaves are sometimes used which may help remove pests such as fleas, ticks and lice due to the strong smell.
Nesting chambers are filled with bedding materials to keep the badger insulated, off the wet mud and to minimise draughts. During harsh winter, windy weather I’ve seen my local badgers use bedding to temporarily block exposed entrance holes.
Badgers will change their bedding regularly to control flea infestations, badger fleas only jump onto the badgers to feed but mainly live in the bedding.
Badger will regularly ‘air’ their bedding, bring it out in to the open, leaving it out close to an entrance hole during a dry, sunny day to kill off pests, before taking back down in the evening.
A couple of times a year they will completely replace all bedding, normally before winter and before the cubs are born.
Michael Clark, author of ‘Badgers’ noted that in one case bedding stayed underground for 14 months.