Chemical Contamination in Bird Nests Linked to Pet Treatments
Songbird chicks are being killed by high levels of pesticides found in the pet fur used by their parents to line their nests, according to a new study.
Researchers from the University of Sussex surveyed nests for harmful chemicals commonly found in pet flea treatments and discovered that the chemicals were present in every single nest examined. They are now calling for a government reassessment of the environmental risks associated with pesticides used in flea and tick treatments.
Insecticides are widely applied to cats and dogs as preventive measures against fleas, often recommended by vets even when pets do not show signs of infestation. However, scientists are now advising that animals should only be treated for fleas if they indeed have them.
Previously, it was known that chemicals from these treatments were harming aquatic life following pets’ swims in rivers, but this latest discovery regarding songbird nest contamination adds further urgency to the issue.
Cannelle Tassin de Montaigu, the lead author of the research paper, stated, "No nest was free from insecticides in our study, and this significant presence of harmful chemicals could be having devastating consequences on the UK's bird populations."
The research indicates that veterinary flea and tick drugs are a likely source of contamination. The study was conducted at the end of the breeding season, suggesting that the situation could be worse.
The study, published in Science of the Total Environment, found that the fur used in nests contained chemicals such as fipronil, which is prohibited for agricultural use in the UK and EU, and imidacloprid, banned in the EU since 2018 for plant protection. Despite these bans, both substances are still frequently used in pet flea treatments.
Researchers collected 103 nests of blue and great tits, discovering that 100% contained fipronil, and 89% contained imidacloprid. There was a correlation between a higher incidence of insecticides and a greater number of unhatched eggs or dead chicks.
Recent studies also found that these flea treatments frequently enter rivers, destroying wildlife and leaving pet owners at risk of contamination for at least 28 days after application.
Sue Morgan, chief executive of SongBird Survival, commented, "It is extremely concerning to see the alarming levels of toxic pesticides in bird nests from veterinary drugs. Pet owners need to be aware that while caring for their pets, they might inadvertently harm the ecosystem."
She emphasised the need for immediate action, highlighting that over half of UK songbirds are threatened or in decline, hence the significance of advocating for a more comprehensive environmental risk assessment of veterinary drugs.
