Seagulls can be such assholes. While it’s probably never right to apply our human sense of morality to nature, you can confirm that seagulls were built to irritate if you’ve ever eaten food along a beach. However, a recent study suggests that seagulls have moved on from their reign of annoyance over humans eating by the seaside to whales.
Scientists have discovered that kelp gulls are attacking southern right whales in Península Valdés, Argentina, when they came up to breathe, pecking at them and eating their blubber while they’re still alive. The results, published in the journal PLOS ONE, suggest that these gull attacks have risen dramatically over the last 40 years, estimating the proportion of mothers and calves showing marks of seagull attacks has increased from two percent in the 1970s to 99 percent in 2011.
Biologists at the University of Utah in Salt Lake City used aerial photography, collected from 1974 to 2001, to look for the presence of gull attack lesions on 2,680 living whales (1,527 mothers and 1,153 calves) off the coast of Patagonia. In 1974, around 2 percent of these whales had lesions caused by the birds. Throughout the '80s this rose to 36 percent, and by the 2000s it was 99 percent.
In the publication, the authors wrote, “During an attack, a gull lands on a whale’s back and gouges out skin, either opening a new lesion or enlarging a pre-existing one. During successive attacks, gulls widen and/or dig more deeply into the dermal and subdermal layers of skin, exposing blubber and creating lesions of various sizes and depths. Kelp-Gull attacks usually occur when whales are resting or surfacing to breathe and their backs are fully or partially exposed to the air.”
The lesions caused by gulls could lead to many problems for the whales. Healing the wounds, as well fleeing from the gulls, requires energy. The study also stated that whales that had been attacked appeared to spend less time nursing, resting, and playing compared to the mother-offspring pairs that had been left in peace.
The study also hoped to find out if sea gull harassment might have increased death rates of calves in Península Valdés. From 1993 to 2002, there was an average of 8.2 calf deaths per year. Since then the rate has risen and risen, with an average of 50 deaths annually between 2003 to 2014.
The study couldn’t draw any clear conclusions on the role of the birds, though, as just 56 percent of the calves found dead had lesions from gull attacks.
No one really understands this behavior from these seabirds. However, other studies have also found increasingly aggressive behavior from kelp gulls. A few months ago, a study reported the never-before-seen behavior of kelp gulls attacking baby seals and eating their eyes.
Main image credit: Amy McAndrews/Flickr. (CC BY-NC-ND 2.0)