{"id":20795,"date":"2022-09-22T16:42:46","date_gmt":"2022-09-22T14:42:46","guid":{"rendered":"https:\/\/www.discoverwildlife.com\/?p=67960"},"modified":"2022-09-22T17:03:13","modified_gmt":"2022-09-22T15:03:13","slug":"bird-disease-spread-by-garden-bird-feeders","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcwildlife\/rss_feed\/bird-disease-spread-by-garden-bird-feeders\/","title":{"rendered":"Bird disease spread by garden bird feeders"},"content":{"rendered":"

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By Stuart Blackman\n \t\t<\/p>

Published: Thursday, 22 September 2022 at 12:00 am<\/p>

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The past 15 years have seen greenfinches shift from ubiquitous garden visitors to something of a rare sight. New research from the British Trust for Ornithology<\/a> (BTO) bolsters the evidence that the infectious disease behind their spectacular decline is spread by the very bird-feeders that attract them to our gardens.<\/p>\n

What causes Trichomonosis?<\/h2>\n

Trichomonosis is caused by a single-celled parasite that creates lesions in the birds\u2019 throats. These interfere with feeding, leading to death by starvation. It was first detected among UK greenfinches<\/a> in 2005, when the suspicion was that they had been infected by pigeons, the primary hosts of the disease, at garden feeders<\/a>.<\/p>\n

Chaffinches<\/a>, too, are susceptible to lethal infection, although their decline was not evident until about 2014. \u201cThey were our second commonest species; they\u2019re now our fifth,\u201d says the BTO\u2019s Hugh Hanmer. \u201cWe\u2019ve lost about two and a half million pairs between the two species.\u201d<\/p>\n

What does the study show?<\/h2>\n

The BTO\u2019s new study, published in Scientific Reports<\/em><\/a>, draws on data from its Garden BirdWatch<\/a> and breeding bird surveys, as well as nest<\/a> and ringing records. It shows that the finches\u2019 declines coincide with the rise of trichomonosis infections among garden visitors, which in turn reduced adult survival.<\/p>\n

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The UK chaffinch population is collapsing. The BTO is to reconsider guidelines to householders in the light of new research on how trichomonosis is transmitted. \u00a9 Alphotographic\/Getty<\/span><\/figcaption><\/div>\n

The steepest declines occurred in garden<\/a> habitats. The \u201clogical conclusion,\u201d says Hanmer, is that garden feeders are a major source of infection.<\/p>\n

He is concerned that the infection might yet spread to other, rarer species, less able to weather a population crash. \u201cThe hawfinch<\/a> is probably the obvious one,\u201d he says. \u201cAnd there\u2019s evidence that they can catch it.\u201d<\/p>\n

There is little doubt that garden feeding brings benefits to bird and human populations alike. But the study shows there are also costs. \u201cIt\u2019s a trade-off,\u201d says Hanmer. \u201cWe are currently talking about how to give better guidance.\u201d This might, for example, mean advising householders<\/a> to feed birds<\/a> only winter. But it\u2019s not impossible that the cons prove to outweigh the pros.<\/p>\n

\u201cBTO is a science-led organisation, and if that\u2019s what the facts were to tell us, then that is what we would communicate,\u201d says Hanmer. \u201cBut we\u2019re nowhere near that at the moment.\u201d<\/p>\n

More wildlife news<\/h4>\n