Alaska's seabirds lost 95% of their breeding population, but after mink were removed from the Naked Islands, guillemots rebounded 3.3 times, and nests surged
Conservation programs often focus on restoring habitat, but sometimes the biggest obstacle is an invasive predator. That was the case on Alaska’s Naked Island Archipelago in Prince William Sound, where pigeon guillemots (
) once formed the region’s largest breeding colony. Between 1979 and 2008, however, the local population crashed by about 95%, a decline linked to the introduction of American mink and compounded by the effects of the 1989 Exxon Valdez oil spill. With so few breeding birds remaining, scientists feared the colony might never recover. Instead, a decade-long restoration effort has revealed how quickly seabird populations can respond when a major predator is removed. A new study found that following targeted mink removal beginning in 2014, guillemot numbers rebounded dramatically, providing one of the clearest recent examples of successful island ecosystem restoration. According to The Journal of Wildlife Management
, shoreline surveys recorded a 3.3-fold increase in guillemot numbers by 2023 compared with the start of the restoration effort.
Removing one invasive predator changed the islands
American mink are not native to Prince William Sound but became established on several islands, where they preyed heavily on eggs, chicks, and adult seabirds nesting in rock crevices close to shore. Beginning in 2014, wildlife managers launched an intensive program to remove mink from guillemot nesting areas throughout the Naked Island Archipelago. Researchers monitored breeding colonies over the following decade and documented rapid improvements. Active nests increased 4.7 times during the first five years after mink removal, while more birds began nesting in crevices that had previously been too dangerous because they were easily accessible to predators. Nestling survival also improved substantially. The researchers believe many of the returning birds immigrated from nearby mink-free islands, quickly recolonizing habitat that had become suitable again. In contrast, guillemot numbers at nearby islands without mink declined slightly during the same period, suggesting the recovery was directly linked to predator removal rather than broader regional population growth. According to the study, the speed of recolonization demonstrates how rapidly seabird populations can respond once invasive predators are eliminated.
) once formed the region’s largest breeding colony. Between 1979 and 2008, however, the local population crashed by about 95%, a decline linked to the introduction of American mink and compounded by the effects of the 1989 Exxon Valdez oil spill. With so few breeding birds remaining, scientists feared the colony might never recover. Instead, a decade-long restoration effort has revealed how quickly seabird populations can respond when a major predator is removed. A new study found that following targeted mink removal beginning in 2014, guillemot numbers rebounded dramatically, providing one of the clearest recent examples of successful island ecosystem restoration. According to The Journal of Wildlife Management
American mink are not native to Prince William Sound but became established on several islands, where they preyed heavily on eggs, chicks, and adult seabirds nesting in rock crevices close to shore. Beginning in 2014, wildlife managers launched an intensive program to remove mink from guillemot nesting areas throughout the Naked Island Archipelago. Researchers monitored breeding colonies over the following decade and documented rapid improvements. Active nests increased 4.7 times during the first five years after mink removal, while more birds began nesting in crevices that had previously been too dangerous because they were easily accessible to predators. Nestling survival also improved substantially. The researchers believe many of the returning birds immigrated from nearby mink-free islands, quickly recolonizing habitat that had become suitable again. In contrast, guillemot numbers at nearby islands without mink declined slightly during the same period, suggesting the recovery was directly linked to predator removal rather than broader regional population growth. According to the study, the speed of recolonization demonstrates how rapidly seabird populations can respond once invasive predators are eliminated.
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