Yes – trichomoniasis has had a very devastating impact on Ireland’s Greenfinch population in a few short years.

The Irish Garden Bird Survey has proven important in documenting their decline since trichomoniasis arrived. In the 1990s and early 2000s. Greenfinches were recorded in around 90% of Irish gardens each winter. Since winter 2008/09 their numbers have fallen considerably and by winters 2016/17 and 2017/18, they were only in 70% of gardens. The average size of flocks also dropped considerably, from peak counts of 7 birds visiting gardens each winter in the late 1990s, to average peak counts of only 3 birds in recent years.

The Irish breeding population of Greenfinches is monitored each summer through the Countryside Bird Survey and Greenfinch are now at around half the levels they were when the survey began in the late 1990s.

The dramatic declines seen in Irish Greenfinches is reflected in similar declines in the UK and Europe, where trichomoniasis has taken hold. Other finch species, most notably Chaffinch and Goldfinch, also suffer from this infection. Chaffinch numbers in the UK took a brief dip when trichomoniasis initially appeared, but they have largely recovered since. Goldfinch numbers have been on the rise for the last two decades in Ireland and further afield, and thankfully trichomoniasis has done little to slow that increase.