05-07-2025
Meet 2 Extinct Birds Of Mexico's Most Isolated Island. Hint: One Is A Type Of ‘Elf Owl'
You might be surprised to know that Mexico is home to over 1300 islands. Here are details on its ... More most remote island, as well as two beautiful bird species that have perished from its delicate ecosystem.
Several factors cause some bird species to be more prone to extinction than others. One factor is range: birds limited to an island geography are more likely to go extinct than continental birds. And, the smaller and more remote the island, the greater the risk.
This unfortunate fact has played out in islands all over the world. In Cuba, the Cuban kestrel likely vanished shortly after European colonization began in the 1500s. In Guadalupe Island, the Guadelupe caracara went extinct largely due to extermination efforts by 19th-century settlers who falsely thought the bird was a threat to livestock.
This pattern can also be found in Mexico's most remote island, Socorro Island, which sits approximately 375 miles off the coast of Mexico's western shore. Here's the story of the two extinct bird species of Socorro Island.
Socorro Elf Owl
The Socorro elf owl is an extinct subspecies of elf owl, whose relatives range from the Southwest ... More U.S. to Central America.
The Socorro elf owl (Micrathene whitneyi graysoni) was a tiny, nocturnal bird found in the arid forests of Socorro Island. A subspecies of the mainland elf owl, it was smaller and more furtive – adapted to life in the dense, shrubby habitat of the volcanic island. Sadly, it hasn't been seen since the early 20th century and is now presumed extinct.
The primary driver of its extinction was likely the introduction of feral cats, brought to the island by naval crews and settlers. With no natural predators on Socorro prior to human arrival, the elf owl, along with other native species, had no defenses against the hunting prowess of these invasive predators. Habitat degradation caused by feral sheep also likely played a role in its decline, reducing the availability of nesting sites in tree hollows and shrubland.
Socorro Dove
The Socorro dove is extinct in the wild and was once found only on Mexico's remote Socorro Island.
The Socorro dove (Zenaida graysoni) met a similar fate. Once abundant on the island, this ground-foraging dove – with an earthy red-brown plumage and a quiet, mournful call – disappeared from the wild by 1972.
Like the elf owl, the Socorro dove suffered heavily from cat predation and habitat loss. Fortunately, it was saved from total extinction by a small captive population that had been sent to zoos in the U.S. and Europe decades earlier. Thanks to careful breeding programs, more than 100 individuals now exist in captivity, and reintroduction efforts are underway.
Rebalancing The Delicate Ecosystem Of Socorro Island
Were it not for the introduction of invasive cats and sheep to the island ecosystem, the elf owl and Socorro dove would have likely never perished. To that end, scientists and government officials have been working together to remove the invasive pests from the island. One such effort is described in a 2019 paper by a group of Mexican and American scientists, led by Antonio Ortiz-Alcaraz.
The eradication of feral sheep began with aerial surveys and was carried out in stages between 2009 and 2012. Helicopter sharpshooters removed over 1,200 sheep in just one week of aerial hunting. The remaining animals were tracked using radio-collared 'Judas sheep' (sheep that serve to help locate remaining herds) and dispatched by ground teams. A total of 1,762 sheep were removed.
Socorro Island, part of the Revillagigedo Archipelago, lies 375 miles off Mexico's Pacific coast and ... More harbors the highest level of island endemism in the country.
At the same time, a feral cat eradication program began. Using over 250 baited trap sites and more than 50,000 trap-nights, researchers captured and euthanized over 500 cats by 2016. Trapping was most successful in the dry season, and efforts were aided by remote-trigger telemetry systems and night hunting. With both cats and sheep removed or drastically reduced, the fragile native ecosystem is showing signs of recovery, paving the way for the possible return of the Socorro dove to the wild.
These efforts offer a hopeful model for island ecosystems struggling to absorb the impact of invasive predators and grazers.
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