Avian pox is caused by a virus and over the last few years we have seen sporadic cases of the disease in British garden birds.
Although many of the sporadic cases have involved birds like Wood Pigeon and Dunnock, we have seen an increasing number of cases during late summer in Great Tits.
Pathology & disease spread:
Affected birds develop warty or tumour-like growths, often on the head (around the eyes or beak), wings or legs. The growths can become very large and may impede the bird by, for example, restricting vision. This can lead to increased risk of predation or of secondary infection. The growths are usually grey, red, pink or yellow in colour.
Transmission appears to be by one of three routes: namely, biting insects (e.g. mosquitoes), bird to bird contact or indirect contact, the latter through contaminated bird feeders or feeding surfaces. The virus is relatively resistant and can persist for long periods outside of the host. Avian poxes do not appear to be infectious to humans or other mammals.
What you can do:
Follow sensible hygiene precautions as a routine measure when feeding garden birds and handling bird feeders and tables. Clean and disinfect feeders and feeding sites regularly. Suitable disinfectants that can be used include a weak solution of domestic bleach (5% sodium hypochlorite) or other specially-designed commercial products. Always rinse feeders thoroughly and air-dry before re-use. Rotate positions of feeders in the garden to prevent the build up of contamination in any one area of ground below the feeders. Empty and air-dry any bird baths on a daily basis.
If you wish to report finding dead garden birds, or signs of disease in garden birds, you can do so through Garden Wildlife Health, our online reporting system.