Half a million garden birds killed in Britain by disease spread by dirty feeders and infected baths

By Daily Mail Reporter

Dwindling: The numbers of greenfinch in British gardens fell by a third in one year because of the disease trichomonosis

A disease which has wiped out half a million of Britain's best-loved birds is being spread by feeders and baths, it has been revealed.

Gardeners may be unwittingly killing the birds because dirty feeders and infected bird baths help to spread the bacteria Trichomonas gallinae - which makes their throats swell and causes them to starve to death.

Greenfinch populations in central England dropped by a third within a year of the emergence of the disease and the numbers of chaffinches fell by a fifth.

Isolated cases have also been found in sparrowhawks and other garden birds.

Mike Toms, of the British Trust for Ornithology (BTO), said: 'We reckon we have lost about half a million birds in all which is unprecedented.

'Hygiene is the key. It is important people wash their feeders and bird baths every couple of weeks while they are putting food out and temporarily stop feeding birds if there are signs of infection in their garden.

'Trichomonosis is well-known in wood pigeons who have moved into gardens as a major source of food because of changes in farming pratice.

'We believe the pigeons are leaving the parasite on bird tables and baths.'

He added that disease appeared to be mainly effecting finches, possibly because something in their physiology made them more vulnerable to infection.

The disease is caused by a parasite that lives in the upper digestive tract of birds and is spread when they feed each other.

Threat: A chaffinch prepares to wash itself in a bird bath. The disease causes birds' throats to swell and they starve to death as a result

Around 20 million people in Britain regularly leave out food for the birds. They spend £250million a year on specialist seeds.

Mr Toms and colleagues from the Garden Bird Health Initiative (GBHi) - an alliance of conservation groups - published a report in PLoS ONE which revealed most of the birds died in the summer and autumn months.

Outbreaks of the disease - which has also been a traditional killer of doves - have continued to occur every year since its emergence in 2005.

But the researchers revealed it appears to have jumped the species barrier in 2005 and the ability to mutate has made it difficult to assess the impact.

Dr Rob Robinson, principal ecologist at the BTO, said: 'These findings demonstrate that virulent infectious diseases can cause sharp population declines in common wild birds in just a short period of time.'

The study used data drawn from public observation, a volunteer survey and post mortem examinations of hundreds of birds collected from gardens.

Vulnerable: Gardeners are being advised to watch feeders and bird baths every two weeks to prevent the spread of the disease

James Kirkwood, chief executive of the Universities Federation for Animal Welfare and founder of the GBHi, said: 'Health surveillance of British wildlife species is crucial for us to recognise new and emerging disease threats that not only adversely affect the welfare of individual animals but have the potential to impact entire populations.'

Outbreaks are most severe and frequent between August and October. Sick birds are obvious as they tend to stay close to feeders and water sources and often die there.

Members of the public can report cases of the disease at www.rspb.org.uk/advice/helpingbirds/health/sickbirds/greenfinches.asp

source: dailymail