Supplementary feeding of wild birds indirectly affects the local abundance of arthropod prey

Orros, M. E. and Fellowes, M. D. E. ORCID: https://orcid.org/0000-0001-5431-8637 (2012) Supplementary feeding of wild birds indirectly affects the local abundance of arthropod prey. Basic and Applied Ecology, 13 (3). pp. 286-293. ISSN 1439-1791 doi: 10.1016/j.baae.2012.03.001

Abstract/Summary

Providing supplementary food for wild birds is a globally popular past-time; almost half of the households in many developed countries participate and billions of US dollars are spent annually. Although the direct influence of this additional resource on bird survivorship and fecundity has been studied, there is little understanding of the wider ecological consequences of this massive perturbation to (what are usually) urban ecosystems. We investigated the possible effects of wild bird feeding on the size and survivorship of colonies of a widespread arthropod prey species of many small passerine birds, the pea aphid [Acyrthosiphon pisum (Harris); Hemiptera: Aphididae], in suburban gardens in a large town in southern England. We found significantly fewer aphids and shorter colony survival times in colonies exposed to avian predation compared to protected controls in gardens with a bird feeder but no such differences between exposed and protected colonies in gardens that did not feed birds. Our work therefore suggests that supplementary feeding of wild birds in gardens may indirectly influence population sizes and survivorship of their arthropod prey and highlights the need for further research into the potential effects on other species.