PROLOGUE: CHARLY SMELLS A RAT
Juan Carlos Ruiz Miranda had spent many early mornings chasing furry pests from his garden on Isla Natividad, a windy stretch of sand off Mexico’s Baja California Peninsula. If it wasn’t an invasive ground squirrel, known locally as the juancito, bothering his plants, it was a tiny cactus mouse—Natividad’s only native terrestrial mammal. But one morning before dawn in spring 2019, as he returned home from a shift at the water treatment facility, Charly (as he’s known to Natividad’s 300-odd residents) spotted an unusual body skittering past his mallow bush. Its outline was that of an out-of-place critter, but since he saw barely a shadow, Charly dismissed it.
He next glimpsed the four-legged creature about a month later, in the wee hours of June 14. This time he shone a flashlight into his shrubbery to get a better look. The figure’s long tail, protruding ears, and fuzzy posterior were way too bulky to be those of a cactus mouse. When it darted back through the beam, Charly became certain: His tiny island harbored a big rat.
In most locales, a predawn rat sighting would cause no greater alarm than a shudder, since members of the genus Rattus have set up shop in ecosystems around the globe. But after nearly two decades of working on Natividad, and having grown up on a neighboring island, Charly knew this sensitive ecosystem had evolved without the presence of rats—or any mammalian predators.
He also knew that what Natividad lacks in mammals, it makes up for in birds: auklets, cormorants, pelicans, ospreys, and herons, to name just a few. More importantly, he knew this four-milelong island hosts the planet’s largest colony of Black-vented Shearwaters—gray pelagic birds known for their shoreline flights, raspy cries, and nocturnal tendencies. A whopping 95 percent of the species hatch within a few miles of Charly’s yard, in labyrinthine underground burrows that honeycomb the island’s south end. For ages their hidden nests and crepuscular habits were the only defenses the seabirds required.
Like many Natividad residents, Charly as not just a bird bearing the name of his nation, but one connected to the soul of his island. To Natividad’s humans, this shearwater is bird. Its name adorns a rainbow-hued mural of bird wings on the community center wall—a battle cry to protect the unique winged creatures of Charly’s home. And rats, he knew, might spell disaster for the beloved bird, so Charly ran to raise the alarm.
