Common birds during winter in the face of urbanization, foraging ecology questioned thanks to an original citizen science scheme (BirdLab)

Abstract

Supplementary feeding of birds during the winter is a widespread phenomenon in temperate countries. While such practice can boost individuals' winter survival, not all species are likely to use bird feeders. We were particularly interested in examining if feeders on private gardens adjacent to areas impacted by agriculture could benefit farmland birds.

Since 2014, the French Museum of Natural History started an ambitious citizen science schemes named BirdLab to observe the bird communities and the intra- and inter-specific interactions on a pair of birdfeeders by asking participants to reproduce the movements (arrival, feeder switch, and leaving) of each bird on two identical birdfeeders (platform or tube), on their smartphone or tablet by drag and drop small characters representing species, for a protocol of exactly 5 minutes. Four seasons after, this with more than 25000 five minutes' samples that observe around 500000 birds of 27 easily recognisable species among the most common species that used the birdfeeders in France.

Thus, after work to verify that the expertise level of contributors does not affect the quality of data provided by this citizen science scheme, we use this big and well-standardised dataset to study winter bird diversity at feeders at the national level of France. In particular, we examine whether the proportions of artificial and agricultural territories, forests and semi-natural environments, wetlands and water areas in the buffer zone of 500 m around the feeders affect the avian diversity multifaceted indicators (as the number of visits, species richness, trophic index, and Shannon's index). As expected, the diversity of species recruited to feeders increases with the presence of natural elements in the gardens such as trees and edges but also it diminishes with urbanisation, and this even for low gradients of urbanisation. Nevertheless, our results point to a clear synergy between agricultural territories and urban areas around the gardens, with diversity increasing in urban areas adjacent to agricultural territories.

Our result supports the hypothesis that private gardens may participate in the conservation of declining farmland species, and with some precautions to limit the risks associated to the local increasing bird densities on feeders (predator attack, epidemic risk), they offer an alternative source of seeds to granivorous species, particularly in farmland intensive landscape which does not provide food for animals during the whole winter.

Furthermore, this innovative application and citizen science encourages reconnection to nature and allows highly standardized data production by novice naturalists. In addition, the data provided will make it possible to question the species interactions in the bird feeder context.