Sue Morgan of SongBird Survival warns of dangers such as fur left out for nesting birds by well-meaning pet owners

I was pleased to read Stephen Moss’s account of blue tits starting to sing in his garden as they gear up for nesting season ( Birdwatch: Blue tits are feisty and fascinating but often taken for granted, 11 March ). But while blue tits remain a familiar sight, they, along with many other garden birds, now face a growing number of hidden threats in the very place we imagine them to be safest: our gardens.

Scientific research funded by SongBird Survival has shown how everyday gardening choices can have serious consequences. Around a third of UK gardeners use pesticides, and our studies found that house sparrow numbers, for example, were nearly 40% lower in gardens where the pesticide metaldehyde was used.