Herbivores but not vegans: Deer as nest predators

Deer abundance and occupancy areas are currently increasing worldwide, with unknown consequences for birds. Deer impacts on birds have mainly been assumed to be indirect through mechanisms that negatively influence vegetation complexity and reduce habitat quality. Information on the direct negative impacts on bird breeding success is scattered and rudimentary. Here we documented, through videos filmed with camera traps, non-native deer preying on bird nests. We supported this finding by investigating nest predator behaviour in other areas of the world both in the scientific literature and audio-visual platforms. We suggest that our scientific naturalist records and the collected information might reflect poorly understood deer behaviour, in both native and non-native populations. In areas with a high number of individuals, nest predation by deer could have severe consequences for native birds, causing serious alterations in their breeding biology. Future studies are needed to address questions about the consequences of an increase in deer density on avian populations.