King penguins torn between family and food
Penguins are the cuddly faces of the Southern Hemisphere and among the most recognizable birds known to brave the chilly Southern Ocean. But like so many other charismatic favourites of the animal kingdom — especially those that inhabit the world’s coldest places — they’re starting to suffer the effects of climate change.
The king penguin, an iconic black, white and yellow bird second only in size to the emperor penguin, is among the latest species to feel the heat. King penguins raise their chicks on the sub-Antarctic islands north of Antarctica and dive for fish in the frigid waters at the northern reaches of the Southern Ocean. But their breeding and foraging behaviours may be at risk as ocean temperatures heat up in the Southern Hemisphere.
New research shows that warm sea-surface temperature anomalies in the region can cause shifts in the marine environment where they feed, forcing the birds to travel farther and dive deeper for their food — and causing declines in their populations.
A study published Tuesday in the journal Nature Communications shows that climatic changes — and their resulting effects on marine food webs — can have serious implications for king penguin populations.
King penguins typically forage for food in an area of the Southern Ocean known as the Antarctic polar front, a region where the colder water in the south meets the warmer water to the north and draws an abundance of plankton, krill and fish. In some years, though, if seasurface temperatures in the northern part of the Southern Ocean get too warm, the polar front can be pushed southward. This means king penguins have to travel farther from their island homes to get to the best feeding areas.
The study’s authors, led by Charles Bost of the Chize Centre for Biological Studies at the French National Centre for Scientific Research, tracked the foraging patterns of king penguins living on the Crozet archipelago in the southern Indian Ocean between 1992 and 2010.
The researchers found that in warm years, the Antarctic polar front shifted south, forcing the penguins to travel significantly farther to get to their prime feeding grounds. This is especially problematic for the birds during breeding season, when penguin parents take turns incubating eggs and raising chicks and must travel back and forth between the islands and the polar front much more often to relieve their partners of parenting duties.
Having to travel so much farther on these foraging trips could have damaging effects on the king penguin population. The effects for the king penguin could be even more severe if the polar front continues moving farther south each year. During the breeding season, king penguins can spend about 22 days at sea before coming back to relieve their partner and take care of the chicks. One concern is that the front could move beyond this travel distance.
The study provides an early look at the future of marine animals in the Southern Ocean if sufficient action isn’t taken to halt global warming. And it’s a future that could end up without some of the world’s most recognizable and beloved animals.