Seabirds evolved about 60 million years ago, when Earth’s continents drifted to their present positions and modern oceans formed. They spread over thousands of peaceful islands in the vast sea. And as flying dinosaurs and giant omnivorous marine reptiles went extinct, seabirds also began to fill an ecological niche as ecosystem engineers.
They distribute nutrients, in the form of bird droppings, beneficial to plankton, seagrasses, and coral reefs, thereby feeding populations of fish eaten by seabirds and marine mammals in a growing cycle. into a biocarbon pump. The more powerful the pump, the more carbon dioxide it pushes into the sediment storage on the seafloor.
Seabird populations of almost unimaginable size, capable of surviving through periods of profound climate change and geological upheavals of colliding continents, play a profound role in ocean carbon cycle. But even on the most remote islands, they are quickly overrun by humans, who have settled and industrialized the planet over the past 200 years.
By some estimates, the total global seabird population has declined by as much as 90% during that time, with a decrease of 70 percent only since 1950. Seabirds are the most threatened group of birds and one of the most endangered. International Union for Conservation of Nature. Of the 346 seabird species, 97 are globally threatened and another 35 are listed as threatened. Nearly half of all known or suspected seabird species are experiencing population decline.
Most of the damage is caused by invasive predators—the people themselves and the rats, cats, dogs, and pigs they take with them as they mine island after island. After millions of years of evolution without predators, the birds failed to recognize the new species as a threat. They are particularly vulnerable because they do not breed as prolific as many land birds and spend a long time nurturing their flightless young.
There is also direct human predation on an industrial scale, with the harvesting of seabird eggs for food, their droppings as fertilizer, and the birds themselves for oil — and with seals, sea lions and whales — or as a by-product of commercial fishing boats. On the Farallon Islands near San Francisco, home to the largest nesting colony of seabirds in the United States, seabird populations dropped from 400,000 to 60,000 in just a few decades during the gold rush, when people harvest up to half a million eggs a year.
Today, the Farallon Islands are protected as part of a marine reserve, and seabird nests are recovering, helping to maintain the surrounding marine ecosystem, including great white sharks, the apex predators. sometimes feed on populations of northern fur seals that have returned to the island since they were protected. The rhinoceros auklet, a relative of the puffer fish, has also returned, and more than 20 species are threatened and extinct—birds, reptiles, insects, marine mammals, and even sea turtles—lives on and around islands.
The comeback has begun
And there are hundreds of other seabird restoration projects around the world that show signs of success Dena Spatza scientist with Conservation of the Pacific Rim, a non-profit organization focused on ecosystem repair. Spatz is the lead author of the April 10 article learn inside Proceedings of the National Academy of Sciences that thing aggregate data from 851 restoration projects in 36 countries targeting 138 seabird species over the past 70 years.
New research focuses on active efforts to bring back bird populations, including methods of social attraction, such as the use of decoys, as well as direct transfer of young birds to new locations where there are no animals. invasive predators. In more than 75% of the recoveries, the target species visited the sites and started breeding within two years.