Guadalupe Storm Petrel - Disappearance

Disappearance

The introduction of cats to the island decimated the population during the late 19th century. By the end of the 1906 breeding season, it was still considered "abundant" though of course the "large numbers" of birds present there and then must have been nearly the entire population of this species. Still, it was noted that

"he mortality among these birds from the depredations of the cats that overrun the island is appalling - wings and feathers lie scattered in every direction around the burrows along the top of the pine ridge."

The last two specimens were supposedly collected between May 2 and May 5, 1911 and the last record of a breeding bird was in 1912. The species has not been seen since. Only old, abandoned burrows and the decayed remains of storm petrels killed by cats were found in the years thereafter. However, the Guadalupe Storm Petrel cannot be distinguished from the sympatric O. leucorhoa in the field, and surveys on Guadalupe invariably took place outside the breeding season of O. macrodactyla, focussing on researching the local Leach's Storm Petrels. Thus, there remained some hope for the present species' survival, or rather, its extinction could not be definitely confirmed.

From June 4 to June 10, 2000, the Guadalupe Storm Petrel's breeding grounds were finally surveyed at the correct time. Had the species survived, not only would recently fledged immature birds have been present, but also all signs of a recently ended breeding season, such as eggshells and freshly used burrows retaining the musky smell of these birds. In the words of the expedition's primary researcher, Exequiel Ezcurra of the San Diego Natural History Museum,

"We searched thoroughly for the Guadalupe Storm Petrel, and failed to find it. Sadly, we are now more ready to admit that the species is indeed extinct. Never, since the 1920s, had so much search effort been devoted to this species. At different times, more than 10 researchers looked for the elusive creature. It simply was not there."

The official classification by the IUCN has not been updated yet. In any case, the precautionary principle would probably require a few years of follow-up surveys, possible now that restoration of Guadalupe's ecosystem is underway.