In the frigid waters off Argentina's southern Valdés Peninsula, the southern right whale is under attack from an odd-sounding predator: the seemingly docile seagull.
Uncovered garbage dumps and waste from fish-processing operations have fueled a spike in the number of kelp gulls in the region's coastal towns (Argentina map).
Experts say the birds, which nest near the prime breeding waters for the endangered whales, are causing a peck of problems.
"The gulls are landing on the whales and pecking through their skin to feed on the blubber, which is an important source of calories," says biologist Marcelo Bertellotti of Argentina's Patagonia University.
"This is causing lesions and impacting whale behavior." The kelp gull is a flexible eater that hunts insects and scavenges through trash heaps.
But it is especially fond of whale blubber, normally dining on dead animals or snatching up blubber dislodged by the whales' trademark somersaults, Bertellotti says.
However, some aggressive gulls go further for a meal.
"Some individuals have developed the capacity to take skin and blubber from live whales," he said.
Mothers and Calves Attacked
Researchers don't know what causes some the birds to get aggressive, but they note that the attacks often create wounds and, in some cases, transmit viruses and bacteria.
Bertellotti and Fundación Vida Silvestre Argentina (FVSA), an organization associated with the World Wildlife Federation, say the kelp gulls' pesky gouges force whales to dive and flee.
That interrupts crucial rest and feeding periods, forcing the animals to expend energy normally used to make fat layers for long migrations or to produce mother's milk.
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