One male Greenfinch in my Garden in Fulbeck with this disease yesterday.......
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Disease outbreak in FinchesGreenfinch populations in central England dropped by a third within a year of the emergence of a new disease, reports a newly published study. Scientists from the Garden Bird Health initiative (GBHi), including those from the BTO, discovered that trichomonosis, an emerging infectious disease of garden birds led to dramatic declines in greenfinch populations across much of England. The findings of their study are described in a paper published in the journal PLoS ONE today. The study also revealed that chaffinch populations fell by up to 20%. Most birds died in the summer and autumn months, and outbreaks of the disease have continued to occur each year since its emergence in 2005.
Dr Rob Robinson, a Principal Ecologist at the British Trust for Ornithology (BTO) joint lead author, commented “These findings demonstrate that virulent infectious diseases can cause sharp population declines in common wild birds in just a short period of timeâ€. In order to determine the scale of the disease outbreak, the study used data drawn from public observation and a volunteer survey. Further data were collected through post mortem examination of hundreds of birds, which were collected from gardens across the country.
Becki Lawson, a wildlife veterinarian from the Zoological Society of London and joint lead author, said “This citizen science project highlights the valuable role that volunteers can play in helping us learn more about wildlife diseases, even by just watching birds in their gardens for a couple of hours each weekâ€. The GBHi team is now investigating possible factors underlying the emergence of this disease in garden birds and its continued impact on our garden birds.
Trichomonas gallinae, the cause of the disease, is a protozoan parasite (not a virus). Trichomonas gallinae is well known as a cause of disease in pigeons and doves, and birds of prey that feed on them. In 2005, trichomonosis was first recognised as a cause of disease in British finches. The greenfinch (Carduelis chloris) has been most frequently affected; the chaffinch (Fringilla coelebs) is the second most frequently affected species, although a range of garden birds have been found to be susceptible to the parasite
Trichomonas is vulnerable to desiccation and cannot survive for long periods outside the host. Transmission of infection is most likely to be through birds feeding one another with regurgitated food during the breeding season; or through food or drinking water contaminated with saliva.
Trichomonosis outbreaks are most severe and frequent in the period of August to October. Sick birds are obvious, as they have a tendency to stay close to feeders and water sources, and often die there. Lack of birds in the garden without the presence of sick or dead birds does not indicate a disease outbreak, but is most likely caused by the seasonal changes in birds’ behaviour in late summer and autumn.
How can you help?Trichomonosis spreads where the saliva of an infected individual comes into contact with that of non-infected bird. This could occur at garden feeding stations and at bird baths, so it is important to keep these as clean as possible.
If you see a bird in your garden that is fluffed up, lethargic and is perhaps drooling and having difficulty swallowing the BTO recommends that you empty your feeders and bird baths, disinfect them, allow them to air-dry, and then fill them again. Provide only a small amount of food so that old food does not accumulate and provide fresh water on a daily basis. We do not recommend that you stop providing food and water unless you feel confident that naturally occurring alternatives are available near your garden. If you are not sure, then clean up regularly and keep on feeding – many birds could rely on the food and water that you provide and removal of these resources might cause 'your' birds to find less sanitary gardens.
For more advice, request your free Garden Bird Hygiene and Disease leaflet from BTO Garden BirdWatch by emailing
gbw@bto.orgAlso see -
http://www.bto.org/gbw/PDFs/Trichomonas ... _Aug06.pdf
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Andrew Chick Website:
http://www.forktail.co.uk/