D3094: The 17-year Brood X bird feast

Brood X periodical cicadas (Magicicada spp.) emerge in the billions every 17 years, and their overabundance has the potential to shift the diet and behavior of common consumers, including birds. Recent studies in the Western Palearctic found that a wide range of passerine birds will eat cicadas, and more in-depth research has been done on several individual species. However, community-wide effects of Magicicada spp. on the relationship between birds and their annual prey in the Eastern US are poorly documented. Our project quantifies the changes in bird feeding behavior and prey choice during the 2021 Brood X emergence in Poolesville, MD across multiple bird species and dietary categories. We performed observational bird predation surveys to quantify the range of species that fed on cicada versus non-cicada prey. The observational data was compared to the established life history traits available through the Cornell Lab of Ornithology. We found that a diversity of bird species across foraging strategies and size classes take advantage of cicada prey. The most commonly observed avian cicada predators were large omnivores, followed by insectivores. Frugivores and grainivores also seemed to forage for cicadas but significantly less than the other diet classes. Both natural and man-made perturbations can drastically alter complex food webs. By studying this periodical and predictable perturbation of cicada emergence, we can gain context for how ecosystems might react to less predictable perturbations in the future.