Songbird chicks are being killed by high levels of pesticides in the pet fur used by their parents to line their nests, a study has found.

Researchers surveying nests for the harmful chemical found in pet flea treatments found that it was present in every single nest. The scientists from the University of Sussex are now calling for the government to urgently reassess the environmental risk of pesticides used in flea and tick treatments and consider restricting their use.

Cats and dogs are widely treated with insecticides to prevent against fleas. Vets often recommend regular flea treatments as a preventive measure, even when dogs and cats do not have the pest. But scientists now recommend animals should not be treated for fleas unless they actually have them.