Infectious disease hits greenfinch population

Greenfinch populations in central England dropped by a third within a year of the emergence of a new disease, a study has revealed.

Scientists from the Garden Bird Health initiative (GBHi) and the British Trust for Ornithology (BTO) discovered that trichomonosis – an infectious disease of garden birds – led to dramatic declines in greenfinch populations across much of England.

The findings were published in the journal PLoS ONE.

The study also revealed that chaffinch populations decreased by as much as 20 per cent.

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Most birds died in the summer and autumn, and outbreaks of the disease have occurred annually since 2005.

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

To determine the scale of the outbreak, the study used data from public observation and a volunteer survey. Further details were drawn through post-mortem examinations of hundreds of birds collected from gardens across the country.

Becki Lawson, a wildlife veterinarian from the Zoological Society of London and joint study 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 week."

The GBHi team is continuine to investigate factors underlying the emergence of the disease and its continued impact.