Foraging on human-derived foods by urban bird species

Abstract

Capsule: Providing peanuts on bird feeders was shown to attract more individuals and more species than providing cheese or bread. Aims: To investigate how the provision of different human-derived foods affected visit rates of urban birds at bird feeders. Methods: A fully replicated study design was set up in parkland, offering a binary choice from three food types (peanuts, bread and cheese) on bird tables. Birds were observed by using a scan-sample method. Results: Peanuts attracted more visits, and a greater diversity of bird species, than cheese or bread. This preference was strongest for Blue Tits Cyanistes caeruleus and Great Tits Parus major, whereas European Robins Erithacus rubecula visited all food types equally, and Blackbirds Turdus merula preferred cheese. Bread was the most consumed food type when measured by mass, but this could be linked to varying bite sizes. Conclusion: Our results indicate that birds preferred to visit feeding stations with the most protein- and energy-rich foods, but that some birds still chose the carbohydrate-rich bread. The findings indicate that peanuts, rather than household scraps like bread and cheese, attract the highest number of species and individuals to bird tables. The findings will be of interest to the public and to organizations providing information on bird feeding for recreational purposes.