Food Webs and Feeding Habits on the Revillagigedo Islands, Mexico

Oceanic islands, including the Revillagigedo Islands in Mexico, exhibit unique food webs that differ significantly from continental ecosystems due to lower species diversity and the absence of key mainland components. This study reveals that food web complexity increases with island size, driven by greater habitat diversity on larger islands. While seabirds dominate the smaller islands, larger ones support a broader range of vertebrates, including reptiles, passerine birds, hawks, owls, parrots, and doves. Some species, like the Socorro Red-tailed Hawk, have adapted to specialized diets in the absence of small mammals, consuming primarily lizards and land crabs. Seasonal or permanent shifts in feeding habits are also observed, such as cactus consumption by ravens and owls on Clarión, insectivory among towhees, and plant-based diets for red-tailed hawks. These adaptations may stem from harsh environmental conditions or unique island fauna/flora. Insectivorous birds on Socorro mitigate competition through varied foraging strategies. The study also highlights the impact of introduced species, such as sheep, which were eradicated but could have long-term ecological consequences if other exotics persist.

Brattstrom, B. H. (2015). Food Webs and Feeding Habits on the Revillagigedo Islands, Mexico. Pacific Science, 69(2), 181–195. https://doi.org/10.2984/69.2.4