Much of the bird food available in the Netherlands is contaminated with pesticides, including seed mixes sold by bird protection organisation Volgelbescherming, according to new research.

The organic bird food bought at C J Wildlife was the only pesticide-free sample found in the test, carried out by the environmental group Pesticide Action Network Netherlands (PAN).

The other samples came from bird food bought at Albert Heijn, Action, Maxi Zoo and garden centres.

Bird food sold by Vogelbescherming, for sale at Pets & CO and Tuinland, was found to contain piperonyl butoxide (PBO) which was also present in all the other samples. PBO is used to strengthen the effect of insecticides but its consumption affects birds’ hormonal function and therefore their fertility.

Vogelbescherming said in a reaction it is “shocked” by the news and wants to speak to PAN about how damaging the pesticide residues are.

Other pesticides found were deltamethrin, which can affect the nervous system, PAN claimed, as well as the banned insecticides pirimiphos-methyl, pyrethrin, and tebucanozole, an anti-fungus chemical.

PAN recommends either buying organic products or making a homemade mix of organic grains and seeds.