Eagle effects on seabird productivity: Effects of a natural experiment

Abstract

Altered human presence, which resulted from COVID-19 lockdowns, led to instant and wide-ranging effects on wildlife across the globe. While humans have gradually reappeared in nature after the lockdowns, it has remained unclear how persistent these lockdown effects have been on ecosystems. We have earlier reported an unexpected chain of events linked to the closing of the tourist traffic to an iconic seabird island in the Baltic Sea. When tourists disappeared, the number of white-tailed eagles rose dramatically, which had strong negative effects on breeding common murres. Using data from the first post-lockdown season (2021), when human presence increased, we document a sudden return to pre-lockdown conditions with fewer eagles, lowered disturbance of murres and recovered murre productivity. However, eagle disturbances of murres remained in an isolated part of the island, revealing that the interaction between humans, eagles and seabirds occur at a small geographical scale. This suggests that small-scale mediation of human behavior can be effective in mediating animal behavior and thereby allow for co-existence between seemingly conflicting conservation goals.