Neonicotinoids are pesticides widely used in agriculture (seed coating and insecticide treatments) that have been blamed for dramatically impacting invertebrate populations. They attack the nervous systems of arthropods and are believed to present no risk of bioaccumulation along the food chain, but this remains controversial.
In Switzerland, population sizes of the Eurasian hoopoe (Upupa epops) have peaked in the early 2000s but are again on the decreasing side since a few years. The reasons for this new decline are not known with certainty. Among other factors, neonicotinoids could affect this insectivorous bird in two ways. First, by diminishing the abundance of invertebrates, they may lead to dramatic decreases of insectivorous birds. Second, neonicotinoids may amplify, contrary to dominant views, along the food chain and eventually affect hoopoe. However, this second hypothesis has never been properly tested. I am going to visit the nests of the hoopoe and collect samples from the chicks and the parents. These samples will be analysed in the laboratory for the presence of neonicotinoids.