How do chewing lice obtain food from birds and mammals?

Chewing lice, which belong to the order Phthiraptera, obtain food from their hosts through specialized feeding habits depending on whether they infest birds or mammals.1

Feeding on Birds

Avian chewing lice primarily consume feathers, though their diet can also include blood and tissue fluids. They obtain these fluids by gnawing on the host's skin or by feeding on the central pulp of developing feathers. Notably, species that consume feathers are capable of digesting keratin.2

Feeding on Mammals

Chewing lice that parasitize mammals generally feed on skin debris, secretions, and fur. While they are not bloodsuckers like sucking lice, they may occasionally consume blood and tissue fluids.12

These insects possess chewing mouthparts and use their shortened front legs to transport food to their mouths. Although they do not feed directly on the host's blood as their primary source of nutrition, their feeding activities can cause significant discomfort, including itching and loss of appetite in the infested animal.1