The unusual deaths of at least three peregrine falcons in just over a year has sparked a pesticide warning from Guernsey's States Vet.
Post-mortem examinations and investigations into the contents of the birds' stomachs found fatal doses of a mixture of banned professional-use pesticides.
A fourth death is being investigated.
Some of the chemicals have been banned in Europe since 2012.
The first deaths were notified to the States Veterinary Officer in April 2019, when two peregrine falcons were found dead next to each other.
A further death was reported in February 2020 at a different location.
The autopsies showed that the birds were previously in good health, but that they all had historic evidence of gunshot damage.
They had all died from overdoses of a mixture of chemicals.
There are also concerns the birds' deaths could damage wildlife tourism.
The peregrine falcon is an apex predator - it is at the top of its food chain. Its existence shows the success of the species below it and is a good indicator of strong biodiversity.
Any allegations of misuse of pesticides will be investigated by States officials and the States Veterinary Officer will investigate any consequential animal welfare concerns.
If anyone has information relating to the misuse of commercial pesticides then these should be referred to the Health and Safety Executive in the first instance on (01481) 234567, or by via email at email@example.com.