What Dead Birds Tell Us About a Warming World

Seabirds are frequently cited as marine ecosystem indicator species. Since 2014, the North Pacific has experienced multiple seabird mass mortality events (MMEs) collectively encompassing several million birds. During this same period of time several types of warming have occurred, including the northeast Pacific marine heatwave, an El Niño event, and the intensification of arctic/sub-arctic warming in the Bering and southern Chukchi Sea. The relationship between warming events and the likelihood, onset timing, duration, spatial extent and magnitude of MMEs can be explored using citizen/community science beached bird data spanning 30 years of monitoring from four programs stretching from central California north to the Bering Strait region, and involving hundreds of coastal residents. These data indicate that sudden, prolonged warming resulted in a demonstrative uptick in seabird mortality, as the system reset to a lower carrying capacity for these upper-trophic predators.