Down offers first-class thermal properties, & has skillful lofting characteristics. This means that a down traps little pockets of air with efficiency. A little pockets of air provide a thermal barrier. Down has the added property that is may be packed into a super little space.

Once damp or even compressed a thermal properties of the down come far diminished. Around cold situations sleep mats provide a insulation from either the ground for people inside down sleeping bags. In the rain these are necessary to get into the waterproof jacket to stop a down from either experiencing damp.

Birds that provide a feathers can exist as utilized for even more purposes, e.g. to provide meat, or it may be flushed deliberatly sequentially to dislodge a down. As an alternative, a few birds line their nests by having down, & such down may be harvested safely when a young leave a nest.