Lice are wingless insects and are the most common external parasites of birds. They differ from fleas in being flattened horizontally, i.e. from above and below, so that they can lie close to the skin (see Plate 1/10). They have hooked legs which are more widely placed than those of fleas. There is a vast number of species of avian lice, some of which are named after the bird they parasitize or the area of the body they prefer. Lice live continuously on the host, leaving it only to attack another victim. So-called sucking lice are confined to mammals, all bird lice being of the more mobile chewing or biting types. Over forty species have been found on domestic poultry alone. Many of these and numerous other species also flourish on wild and aviary birds. Lice lay sticky, triangular eggs or nits which adhere to the feathers in clusters in their favorite region of the body and after which they are popularly named -- head, body, fluff, shaft and wing lice. Sometimes other adjectives in their names indicate the primary host, or their shape, e.g., pigeon and narrow lice. Lice are of many shapes and sizes and vary from 1-6 mm. in length. The eggs hatch within a few weeks of being laid, the larvae feed, grow, moult their skin several times, and become adults ready for breeding.

In favorable conditions, as for example when birds huddle together for warmth, lice can multiply and spread so quickly that it is possible for one pair to produce 100,000 descendants in a few months. It can therefore be appreciated how overcrowding can lead to an explosion of the louse population and result in debility of the bird, paving the way for other diseases which may even lead to death. Bird lice feed mainly on the surface layers of the skin, feather vanes and skin debris, but at least one species has been found to bite growing feathers, sucking the blood from the base of young quills or even gnawing at the skin surface until blood is drawn. Lousiness can be more than a mere nuisance; it can cause irritation, restlessness, loss of appetite and sleep. The condition of the plumage deteriorates and becomes ragged, whilst excessive preening may lead to feather-plucking or even cannibalism. Lice in small numbers, however, may be relatively harmless and most healthy birds harbor a few.

Treatment & Control:
In spite of the diversity of species, one form of treatment suffices for all lice. Because of the relatively short life cycle and the fact that lice rarely leave one bird except to go to another in close contact, control is easy. Dusting powders, bathing solutions, and vapours have all been found satisfactory. The older and more poisonous insecticides such as sodium fluoride and nicotine sulphate, have been largely superseded by more modern ones. Solutions in the form of sprays containing pyrethrum, "Alugan", gammexane, and other substances recommended for eradication of fleas etc., are efficient and more persistent than dusting powders and vapours. With the exception of pyrethrum, (the least stable), they need to be used with considerable care, especially on small passerines as some are toxic to some species of birds. A binding agent is usually incorporated in insecticides which retains the insecticidal action in the plumage for some weeks, thereby killing the next generation of larvae as they hatch. Some of the eggs are also dislodged and washed away during spraying of the plumage. The owners of valuable birds are sometimes reluctant to use sprays, lest a chill or pneumonia should follow. The risk, however, is negligible provided the birds are allowed to dry in a warm atmosphere and cooled off slowly afterwards. It is wise to spray the cleaned premises at the same time as the birds, in order to remove the odd parasite which may have left its host. Regular checks of all stock should be carried out to determine when treatment is necessary. Please check with your local vet or pet shop to see what is the newest and safest treatment for any of the above.


E-Mail: berniehansen@sympatico.ca



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Hamilton & District Budgerigar Society Inc.