04/09/2026
Feeding stations providing food and water for wild birds are contributing to the spread of disease-causing parasites among farmland birds, researchers have said, with birds three times more likely to catch a parasite from these resources.
The Trichomonas gallinae parasite is widespread worldwide in birds from the pigeon and dove group, also known as columbids, where it is a conservation threat to some endangered species such the turtle dove.
The parasite also causes a lethal disease in another class of birds known as passerines, which are common in gardens and include well known songbirds like finches, warblers, and sparrows.
One hypothesis has suggested that this parasite might be transmitted at shared food and water resources which are commonly used on farmland to help wild bird populations.
To test this idea, a research team including Keele's Dr Jenny Dunn used DNA sequencing to screen 363 birds in the UK and France, as well as 51 shared food and water resources, at 12 farmland sites over a two-year period. The DNA tests confirmed the presence or absence of the parasite, and identified which strains were present.
The birds sampled included birds who fed at high density shared food resources where supplementary feed stations were set out, as well as from low density, natural sources like seed-providing vegetation.
One strain of the parasite, known as Type A, was more than doubly prevalent in the birds who fed at high density resources compared to lower density, more natural sites, and it was also found nearly three times as often at the high-density feeding sites themselves compared to the natural feed sites. The Type A strain is a more virulent strain that has been linked to mortalities and population declines in UK greenfinch populations.
Dr Jenny Dunn said: "Our findings demonstrate that the Trichomonas gallinae parasite is much more widespread that we were expecting, and suggest that food and water are key to parasite transmission. However, this knowledge also gives us the tools to manage environmental resources such as supplementary food, to reduce parasite transmission between birds and hopefully reduce mortality."
