Wildlife watchers are being urged to look out for ailing birds this winter, with BirdWatch Ireland making the endeavour part of its annual garden survey.
The request is largely in response to the plight of the greenfinch, which researchers believe have undergone a rapid decline due to an avian parasite thought to have previously infected dinosaurs like tyrannosaurids.
The organisation’s citizen science survey encourages volunteers to note the number of bird species visiting their garden over a set period every year. Now in its 31st year, the latest survey runs from December until February 2020.
Sick finch survey
Following concerns about Ireland’s greenfinch population and the species’ run-in with a deadly disease, the wildlife organisation is making bird health a key feature of this year’s survey.
In the 1990s and early 2000s, greenfinches, small perching birds, were a prominent feature in approximately 90 per cent of Irish gardens.
However, species numbers have since plummeted, according to BirdWatch Ireland statistics. In 2018, greenfinch records fell to their lowest ever numbers.
Experts believe a parasitic infection known as trichomonosis has played a major role in the 30 per cent drop-off.
It’s hoped that birdwatchers and other members of the public will now be able to pitch in and help pinpoint the time when the infection is most apparent.
It means gardeners and wildlife advocates should keep their eyes peeled for struggling birds when pottering around outside.
“The rapid decrease in greenfinch numbers over the last 10 years has been extremely worrying, and last winter’s results suggest their decline hasn’t bottomed out yet,” said Brian Burke, coordinator of the BirdWatch Ireland survey.
“Thousands of people all over the country take part in the Irish Garden Bird Survey every winter, so we’re hoping to use the public’s help to get a better handle on where and when this infection is hitting birds over the winter.
“As well as noting down the numbers of different bird species using their gardens each week, we need participants to tell us about any sick birds they see too,” he said.
Signs of trichomonosis
According to the British Trust for Ornithology, trichomonosis has been observed in UK finch species since 2005 after an epidemic swept through parts of Europe. The disease is believed to have reached Ireland later in 2008.
The parasite is not harmful to humans or other mammals. A major problem, however, is that the disease can spread over large distances due to migration where it is then transmitted to other birds, normally via contaminated or regurgitated food.
Signs that a bird might be infected by the Trichomonas gallinae include fluffed up feathers, difficulty swallowing food, food stuck to beaks, and a reluctance to fly away. While the disease has had a particularly negative impact on the greenfinch, the parasite can be found in other birds like the house sparrow, siskin and pigeons.
“Other finch species can be affected, most notably chaffinches and goldfinches, but their populations haven’t been impacted to the same degree,” Burke said. “Chaffinch numbers did dip when the parasite first appeared, but their numbers have recovered.”
Those taking part in the Irish survey can log their findings online or via post or email. As part of the survey, BirdWatch Ireland also would like people to document the size of their gardens, as well as any bird food on offer.
Burke added: “We get a great response to the survey every winter, and this time around people can give added value to their records by letting us know about any sick birds they see.”