14 DAY TRIAL // You think those naughty little devils called gulls are nothing more than that.
Well, you're wrong! 'Cause they can turn nasty, like Hitchcock's birds.
We associate gulls with uncovered garbage dumps and waste from fish-processing operations, and indeed, these human wastes fueled a boom in gulls populations everywhere. But in the icy cold waters of Austral Seas, their target is big, really big and very alive: the southern right whale. "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."
Kelp gull is a scavenger "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.
This behavior was first observed in 1969. "Some individuals have developed the capacity to take skin and blubber from live whales," he said. The attacks often create wounds and sometimes transmit germs. The gulls attack force whales to dive and flee, interrupting resting and feeding periods. The animals lose energy normally used to fatten for long migrations or milk production. And 80 % of the attacks are aimed at female whales and calves. 25 % of the whales' time is spent fleeing from gulls. "The mothers receive more attacks because they pass more time along the surface when they are with their calves."
"The calves are the most affected because of [their softer skin] during first days of life and because they spend more time at the surface," he added.
The whales are significantly outnumbered by the gulls. The 10,000 southern right whales roam the nursery coast of Argentine, Australia, and South Africa, while kelp gull population reaches 150,000 only in Argentina. The number of aggressive birds has grown with the gull population, due to an increased abundance of human-supplied food sources in coastal areas. "In some places we are seeing a decline or stabilization of gull populations thanks to some changes," said Alejandro Arias, of Fundaci?n Vida Silvestre Argentina, as some communities have covered their landfills.
Tracking devices will let scientists know if whales change distribution due to these attacks, affecting whale watching industry.