Garden pesticides linked to decline in bird numbers
House sparrows were the most affected by garden pesticides, the study found.
Researchers from the University of Sussex have found a significant link between the use of pesticides by gardeners and declining numbers of garden birds such as house sparrows and robins.
The study, published in Science of the Total Environment, drew on data from the British Trust for Ornithology’s Garden Birdwatch survey. 615 participants provided relevant data, of whom nearly a third used pesticides in their garden.
The results showed that there were generally fewer birds in gardens where pesticides were used. The impact was greater in gardens surrounded by high quality habitats, whereas gardens surrounded by low-quality habitats tended to have lower bird populations regardless of pesticide use.
House sparrows were the most effected, with numbers down 12.1 per cent in gardens where even a small amount of pesticide was used. In gardens where metaldehyde was used, numbers fell by 38.6 per cent.
Other common garden birds were affected by pesticides too. Using glyphosate led to a drop in the number of great tits and robins and mecoprop had a negative impact on the abundance of blackbirds, chaffinches, dunnocks and great tits.
The study was supported by the charity SongBird Survival. The charity’s CEO, Susan Morgan, said: “We’re still trying to understand the factors behind the tragic loss of British songbirds, so we are delighted this new study by Sussex University sheds light on why, and how we can help. Brits love their gardens, and as a nation of bird lovers, we must ‘think biodiversity’ and do our bit: Avoid using toxic chemicals or else we’ll continue to see house sparrows, robins, tits and other small birds continue to disappear, their songs silenced forever.”
However, there was positive news. The study also found that creating bird-friendly habitats increased both the number of birds and the variety of species which visited the garden. With an estimated 22.7 million gardens in the UK, this could have a significant impact.
PhD researcher Cannelle Tassin de Montaigu, who authored the study, said: “It’s encouraging to find that simple measures, such as planting native shrubs and trees and creating a pond, together with avoiding the use of pesticides, really make a measurable difference to the number of birds you will see in your garden.”
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