They eat scales or bits of feather, resulting in poor feather quality with serious infestation, although feathers may appear normal if just a few lice are present. Because they are species-specific, this means that if you find lice on cockatiels, there should be very little worry that the lice will spread to other species of birds in the store or home. Lice are usually elongated, whereas mites are more round in shape. The most common feather lice found on birds are usually seen attached to the underside of feathers, along the vanes. They don't easily move around on the bird.
Diagnosis is made by observing the lice or their eggs on the underside of wing and tail feathers.
Several doses 7-10 days apart may be necessary to eradicate lice as they hatch out on the feathers. They complete their life-cycle on the bird and are not a problem for other types of animals. It is a good idea to clean and disinfect the cage housing infested birds. Young birds may be infested by their parents in the nest, or the lice may pass from bird to bird by close contact. One other parasitic insect that you may encounter in pet birds is the stick-tight flea.