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Bird louse at 4x magnification Biting lice belong to the group of ecto-parasites, which are parasites that live outside the bird. These flightless insects affect the feathered areas of their host and feed on the feathers. There are several different varieties of biting lice that all have their own preference in bird species. All bird lice have nearly the same lifestyle, which is the reason for them being summarized in this chapter.

Due to their size, which is up to three millimetres, bird lice can be seen with the naked eye. They are often dark-coloured, have six legs and an oblong, slim trunk. They are light-shy and crawl into the plumage when facing direct light, for example by gently moving the primary wing feathers apart. The picture on the right side shows how a bird louse looks like when enlarged four times.

Since lice live permanently in the plumage of birds, they reproduce there as well. They stick their eggs in columns onto the barbs. Within one to two weeks, the eggs hatch to produce larvae, which turn into adult lice within five weeks.

How to discover a lice infestation
A strong lice infestation manifestation results in bedraggled and thin plumage since many lice have fed on the feathers. Affected birds suffer from itching and lack of sleep as a result. Due to their light-shyness, adult lice are hard to detect for they quickly hide underneath the feathers if these are blown or spread apart.

The eggs and the larvae are discovered more easily. On the underside of the flight feathers (especially on the wings), a brown discoloration can be seen. The tips of individual feathers are corroded and many have holes in the middle.

If an infestation of lice is suspected, an avian vet should be contacted in order to discuss the treatment. Bird lice are generally treated with contact insecticides (poison). A powder containing pyrethrum is often used. It is, however, not without danger for the bird concerned. The bird will get powdered on the underside of the feathers on the wings since the lice tend to predominately live in that area. Spraying the plumage with Exner Petguard, which is only available in Europe, has proven to be a lot more harmless. This treatment contains lactic acid instead of toxins. It sticks together the respiratory openings of the lice, thus causing their death without harming the bird. In other parts of the world similar treatments might be available in pet shops.

It has to be ensured that none of the available anti-parasite treatments - including Exner Petguard - comes into contact with the eyes or the mucosa of the bird!

Which bird species are predominately affected?
Bird lice rarely affect budgies and most other psittacine bird species. They mainly affect pigeons and other wild birds but can also affect pet birds that are kept in aviaries outside and thus come into contact with wild birds. Since a transfer occurs via body contact that enables the lice to move from one host onto another, infection normally occurs only via this route.

German version of this text: Gaby Schulemann-Maier,
translation of this chapter: Melanie Ebenhoch.

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