Scaly mites, Cnemidocoptes pillae, are a microscopic species of mite that cause skin problems (‘scaly face’, ‘scaly leg’ and ‘tassel foot’) by burrowing under the skin in budgerigars, canaries, finches and a variety of other bird species. Cnemidocoptes mutans is a close cousin that causes scaly leg in chickens.
Common signs of disease include scaly, thickened, crusted, flaky skin on bare areas around the face and beak and on the legs. Budgies will typically show scaly face lesions, including beak abnormalities or honeycomb scale on the face and around the eyes. In neglected cases severe beak deformities (e.g. elongated, curved beaks or ‘duck bills’ with overgrowth of both top and bottom beak) can occur if mites burrow into the growing part of the beak. Some budgies will show scaly leg as well as scaly face lesions but scaly leg alone more in canaries, finches and chickens. ‘Tassel foot’ is an advanced form of scaly leg where tassels of deformed keratin scale grow from the sides and bottom of the feet. As well as in canaries, Dr Pat Macwhirter sees this from from time to time in wild European Goldfinches caught from around Melbourne,
How scaly mite is spread
Birds are commonly infected soon after hatching, acquiring the infection from their nest or parents. Older birds can become infected if they come into close contact with infected birds. The mites undergo their full life cycle on the bird, feeding on the outer layers of skin in non-feathered areas such as the beak and legs.
Scaly mite infection can be a reflection of a poor immune system, e.g. often only two or three budgies out of an aviary will show signs of the disease when all will have been exposed to the mites. Sulphur crested cockatoos are rarely affected with scaly mite and birds that are affected often have other underlying disease such as circovirus (beak and feather disease)
Following confirmed diagnosis we typically recommend moxidectin or ivomectin used in accordance with the manufacturer’s recommendations either topically, orally, by injection or in the drinking water along with sparing, topical application of paraffin oil to featherless areas to soften the scale and suffocate the mites. Take care! Birds can be killed by excessive application of oily preparations contaminating the feathers and too vigorous removal of scaly lesions can result in permanent scaring.