On Mallorca, Gull Dinner Features Spanish Olives
Yellow-legged gulls play a long-overlooked role in a Mediterranean archipelago: they carry olives far and wide.
by Lauren Leffer
January 24, 2024 | 700 words, about 3 minutes
The Balearic Islands, a Mediterranean archipelago off the coast of Spain, are a famed travel destination. Clubbers and nightlife enthusiasts flock to Ibiza, while Mallorca is more popular with families and newlyweds seeking sun, sand, sea, and history. To tourists and beachgoers, the islands’ screaming, French fry–stealing gulls are pests. But these ubiquitous birds play a surprisingly important ecological role in the picturesque archipelago.
Two decades ago, ecologist Alejandro Martínez Abraín was studying seabird colonies along Spain’s coast near the Balearic Islands when he noticed something odd. On rocky outcrops and in isolated coves, he found greenish-brown olive pits everywhere, scattered under the webbed feet of hordes of yellow-legged gulls. In most locations, the pits had accumulated in limestone crevices without germinating. But at one colony in the Ebro Delta, about 175 kilometers south of Barcelona, olive saplings were sprouting up from sand dunes.
Wild olive trees are common in Spain, where the Phoenicians introduced the plant more than 3,000 years ago from the eastern Mediterranean. The trees are culturally important, too; people have been cultivating domestic olives and tending to groves in the region since at least the Middle Ages.
In the Ebro Delta, the discarded pits were changing the ecosystem from the grasses and scrubby conifers typical of dune systems to a wild olive forest, says Martínez Abraín, who is now an ecologist at the University of A Coruña in Spain. Connecting the dots, he realized that gulls were eating olives elsewhere and regurgitating the pits in small piles around their breeding sites. “It was really ecological engineering, and nobody was paying attention to that,” he says.
Martínez Abraín began collecting the spit-up pits, but the finding took on new meaning after Haruko Ando, an ecologist and expert in seed dispersal at Japan’s National Institute for Environmental Studies, heard about the olive-eating gulls on a recent visit to Spain.
More:
https://hakaimagazine.com/news/on-mallorca-gull-dinner-features-spanish-olives/