Chemicals in Pet Flea Treatments Are Leading to Songbird Deaths, Report Finds

In a new study, scientists are raising concerns over the ways that flea treatment chemicals for pets can leach into the environment and harm local wildlife. In light of the study, experts are calling on veterinarians to minimize preventative flea treatments to protect songbirds and insects impacted by the chemicals in these treatments.

Scientists from the University of Sussex published a study revealing that nests lined with fur were exposing blue tit and great tit songbirds to chemicals found in common veterinary drugs. The team tested for 20 total chemicals, of which they found 17 present, across 103 different nests.

The most common chemicals included fipronil, found in 100% of the nests, as well as imidacloprid (found in 89.1% of nests) and permethrin (also found in 89.1% of the samples).

Further, the research also revealed that nests with higher number of insecticides, higher concentrations of insecticides, or higher concentrations of fipronil, imidacloprid or permethrin specifically also had higher numbers of unhatched eggs or dead offspring.

“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,” Cannelle Tassin de Montaigu, lead author of the study and a research and associate fellow at the University of Sussex, said in a statement.

As The Guardian reported, some of the chemicals detected in the study have been banned in the UK and the EU, but not for use in veterinary drugs. Fipronil is banned for agricultural use in the UK and EU, and imidacloprid’s use for plant protection is banned in the EU and could soon be banned in the UK for agricultural use. 

In the meantime, experts, including veterinarians, are calling on reduced usage of veterinary drugs for flea and tick prevention. Neither experts nor the study authors are telling pet owners to forgo flea and tick treatments. As recommended by the British Veterinary Association, pet owners should skip year-round, blanket treatments of these chemicals and only use them as needed. 

“We are a nation of pet lovers and bird lovers, and it is extremely concerning to see the alarming levels of toxic pesticides in bird nests from veterinary drugs,” said Sue Morgan, chief executive of SongBird Survival, a charity that funded the study. “Pet owners will be upset to hear that in trying to do the right thing to support their pets with fleas and ticks, they could be harming our ecosystem, resulting in dead newborn chicks and unhatched eggs. As pet owners, we need to have confidence that we are keeping our pets well, without devastating impacts on our wildlife.” 

According to the Natural Resources Defense Council (NRDC), pet owners can prevent and treat fleas through other methods, such as regularly combing pet fur with a fine-tooth comb, and washing pets with warm water and common soaps that are pet-safe, which together can kill fleas without the added chemicals. The organization also recommended that pet owners regularly clean areas where pets sleep and rest, such as their beds or sofas, and minimize fleas by applying nematodes in yards and gardens.

The researchers and SongBird Survival are also calling on governmental agencies to conduct more risk assessments on how veterinary drugs impact the environment, and establish policies to address those risks.