@article{Møller2021, 
author = {Anders Pape Møller and Dorota Czeszczewik and Einar Flensted-Jensen and Johannes Erritzøe and Indrikis Krams and Karsten Laursen and Wei Liang and Wiesław Walankiewicz},
title = {Abundance of insects and aerial insectivorous birds in relation to pesticide and fertilizer use},
year = {2021},
journal = {Avian Research},
volume = {12},
number = {1},
pages = {43},
keywords = {Aerial insectivores, Fecundity of insects, Insect abundance, Insectivores, Insects},
url = {https://www.sciopen.com/article/10.1186/s40657-021-00278-1},
doi = {10.1186/s40657-021-00278-1},
abstract = {BackgroundThe abundance of insects has decreased considerably during recent decades, resulting in current abundance showing 70–80% reductions in more than 15 studies across temperate climate zones. Dramatic reductions in the abundance of insects are likely to have consequences for other taxa at higher trophic levels such as predators and parasites. Pesticides, fertilizers and agricultural land use are likely candidates accounting for such reductions in the abundance of insects.MethodsHere we surveyed the abundance of flying insects, and the reduction in the abundance of insects as a consequence of intensive reduction in agricultural practice linked to fertilizer use and pesticide use. Finally we demonstrated consistency in abundance of birds among study sites.ResultsWe demonstrated that the use of fertilizers and pesticides had reduced the abundance of insects, with consequences for the abundance of insectivorous bird species such as Barn Swallows (Hirundo rustica), House Martins (Delichon urbicum) and Swifts (Apus apus). Juvenile Barn Swallows were negatively affected by the reduced abundance of insects and hence the reproductive success of insectivorous bird species. These effects imply that the abundance of insects could be reduced by the availability of insect food.ConclusionsThese effects of intensive agriculture on insect food abundance are likely to have negative impacts on populations of insects and their avian predators. This hypothesis was validated by a reduction in the abundance of insects, linked to an increase in the abundance of fertilizers and a general change in farming practice.}
}