plumess

Plumess is a term that refers to the soft, downy feathers found on young birds or as an underlayer on adult birds. These feathers are distinct from the larger, more structured contour feathers that form the bird's outer plumage. Plumess is characterized by its fluffy texture and lack of a rigid vane, consisting instead of a central quill with loosely attached barbs. This structure traps air effectively, providing significant insulation against cold temperatures.

The primary function of plumess is thermoregulation. For newly hatched chicks, it is essential for survival as they are unable to regulate their own body temperature effectively. Parental care often involves brooding, where adult birds cover their young with their plumess to keep them warm. As birds mature, plumess continues to play a role in insulation, particularly in colder climates, by forming a layer beneath the outer feathers.

The appearance and density of plumess can vary between species. Some birds, like ducks and geese, are known for their particularly thick and soft down, which has been historically harvested for use in bedding and clothing. The development of plumess is usually a temporary phase, with young birds gradually replacing it with their adult plumage as they grow. However, the insulating underlayer of plumess often persists throughout an adult bird's life.