In 1980, a San Diego newspaper published a eulogy, of sorts, for the wildlife of Mexico’s westernmost possession—Guadalupe, a big volcanic island 150 miles off the coast of Baja California.
“Death of an Island,” read the headline. “Eaten away by goats.”
Once known as Isla de los Pájaros (or “island of the birds”), remote and rugged Guadalupe was home to more endemic bird species than any other island off the Pacific Coast of North America. That came to an end when sealers and whalers arrived in the early 1800s. They brought goats, which leveled the pine and cypress forest, and cats, which killed thousands of birds. Five of eight endemic land birds went extinct. The Guadalupe Storm-Petrel disappeared.
But in the few decades since that grim newspaper article was written, something marvelous has happened on Guadalupe. The goats are gone; the vegetation is rebounding. A colony of Laysan Albatrosses has materialized out of nowhere. Here, and on other once-devastated islands throughout the ocean waters off northwest Mexico, populations of auklets, murrelets, storm-petrels, gulls, terns, boobies, pelicans, and cormorants have been reappearing as if by magic.
Magic … and a lot of hard work. Over the past two and a half decades, Mexican biologists have pulled off a massive effort to reverse centuries of damage and restore these seabird nesting islands. Their success is a gleam of hope, in a world that is losing seabirds fast.
Global Seabird Decline
Many islands around the globe have suffered a biodiversity crisis. More than four-fifths of the world’s bird and mammal extinctions have occurred on islands. The biggest drivers of extinction are invasive mammals: rats, cats, goats, pigs, donkeys, rabbits.
When seafaring humans set foot on an island, they tend to bring other mammals with them—and seabirds suffer. Rats and cats run amok on seabird breeding colonies, eating eggs, young, and even vulnerable nesting adults. Livestock can be just as destructive. When goats chewed away the vegetation on Guadalupe, they caused erosion that affected the storm-petrels nesting in burrows in the forest.
These are pressures that seabirds can’t afford to face. Of the world’s roughly 350 seabird species, about half have declining populations. From penguins in the Antarctic to puffins in the Arctic, seabirds collectively have declined almost 70% since the 1950s, faster than every other comparable group of birds. One consequence of this loss is a broken link in the ecosystem: Seabirds fertilize the plant life on islands with their guano (feces), which is full of marine nutrients from eating fish, squid, and krill.
The seas and shores of Mexico make up one of the most important regions for seabirds in the world. With more than 4,000 islands and islets, Mexico has one-third of the world’s seabird species nesting on its islands or feeding in its waters, and is second only to New Zealand in its diversity of endemic seabirds. But with islands overrun by mammals, Mexico’s seabirds faced a bleak future on their breeding grounds.