The Great Extinction: Unraveling the Most Devastating Single-Species Decline in Modern History

During the breeding period, seabirds depend on fish to nourish themselves and their chicks. However, due to the Blob, there were scant fish available. This scarcity resulted in catastrophic consequences; adult birds and their chicks suffered from starvation. Individuals visiting Alaskan beaches discovered dead and ailing birds. Seals, sea lions, and cod were also affected; and 7,000 humpback whales vacated the vicinity.

Almost ten years have elapsed since the emergence of the Blob, allowing initial evaluations of its probable long-term effects. A study on local avian populations has just been released.

The majority of the avian casualties were what Americans refer to as ‘murres’. This ancient Cornish term for the guillemot and razorbill is onomatopoeic, replicating the guttural moaning call that resonates through seabird colonies. Razorbills remain silent, thus the term is now applied solely to the guillemot.

Approximately eight million murres, which account for a quarter of the global population, traditionally nest on cliff edges along the Alaskan coastline. The Blob has severely impacted them. “Murre populations decreased by 52 to 78% at 13 colonies across two expansive marine ecosystems,” the researchers report.

Bird populations can rebound from such tragedies; wildlife demonstrates resilience. For instance, the frigid winter of 1962/3 caused significant disruption to Irish songbirds.

However, species like the robin produce significantly more offspring each spring than the ecosystem can sustain. A female robin can lay up to three clutches of six eggs each during a season — but due to fierce competition for food and predation, only a few chicks reach maturity. Nonetheless, in the aftermath of a major mortality event, the competition for food decreases and predator numbers decline, leading to lower chick mortality rates.

Songbird populations rapidly bounce back after a decline, but guillemots do not reproduce like robins. They possess a very low birth rate. Prospective parents do not begin nesting until they are four years old, and when they do, they only lay a single egg each year. Consequently, their recovery following calamities is much slower compared to that of robins.

In due time, guillemots should rebuild their numbers, but troublingly, the researchers found no signs of recovery after the Blob.

The extinction of four million murres “is the largest recorded wildlife mortality incident in the modern age,” the authors declare. They express concern that “these ecosystems may no longer sustain historical populations of seabird apex predators.”

Global warming is compromising marine ecosystems globally. If even the guillemot, one of the most successful seabird species worldwide, can be threatened by a relatively localized ‘Blob’, what challenges lie ahead for more vulnerable species in an increasingly warming world?