Baby penguins are now facing yet another challenge to survival: climate change. According to a new report published in the peer-reviewed journal PLOS ONE, altered weather patterns resulting from climate change are causing increased deaths in Magellanic penguin (Spheniscus magellanicus) chicks near Punta Tombo, Argentina.
Between 1983 and 2010, scientists studied 3,496 Magellanic penguin chicks to determine how changing weather is impacting their survival. During two years, rain was the most common cause of death, killing about 50 percent of chicks. Over 26 years, starvation killed the largest number of chicks. Many chicks died in storms and, consequently, fewer chicks fledged (developed waterproof feathers).
According to scientists, the increased frequency and intensity of storms due to climate change has also resulted in more reproductive failure in Magellanic penguins, “a pattern likely to apply to many species breeding in the region.” The study, led by University of Washington biology professor Dee Boersma, concludes that “Climate variability has already lowered reproductive success of Magellanic penguins and is likely undermining the resilience of many other species.”
The area near Punta Tombo on the Argentine coast is home to the world’s largest colony of Magellanic penguins. Scientists note that climate change is killing penguin chicks both directly and indirectly – by depriving them of food as well as causing storms with drenching rainfall and periods of extreme heat.
The chicks are too large for parents to sit over but still too young to have developed waterproof feathers. Downy chicks exposed to heavy rains can die of hypothermia. During periods of extreme heat, the chicks are unable to enter the cooling waters as adults with developed feathers would normally do.
During the 27-year study, rainfall and the number of storms per breeding season – September through February – have increased at the study site. An average of 65 percent of chicks died each year, about 40 percent dying from starvation. “Climate change, a relatively new cause of chick death, killed an average of 7 percent of chicks per year, but there were years when it was the most common cause of death, killing 43 percent of all chicks one year and fully half in another,” scientists said in a press release.
“Starving chicks are more likely to die in a storm,” said Boersma. “Starvation and weather will likely interact increasingly as climate changes.” Once chicks die, parents do not lay additional eggs during that breeding season.
“We’re going to see years where almost no chicks survive if climate change makes storms bigger and more frequent during vulnerable times of the breeding season as climatologists predict,” said Ginger Rebstock, University of Washington research scientist and co-author of the paper.
Also contributing to increasing deaths from climate change is the fact that, over 27 years, penguin parents have arrived to the breeding site later and later in the year, probably because the fish they eat also are arriving later… The later in the year chicks hatch the more likely they’ll still be in their down-covered stage when storms typically pick up in November and December.
This season, heat was a greater threat to chicks’ survival than storms. “Such variability between years is the reason why the number of chicks dying from climate change is not a tidy, ever-increasing figure each year,” a press release by the University of Washington notes. “Over time, however, researchers expect climate change will be an increasingly important cause of death.”
Scientists have long been aware that changing weather patterns and increasingly intense and frequent storms will impact species globally. And while other studies have examined the reproductive effects of single storms and heat waves, Boersma’s and Rebstock’s extensive project is the “first long-term study to show climate change having a major impact on chick survival and reproductive success.”
“There may not be much we can do to mitigate climate change,” Boersma said. “But steps could be taken to make sure the Earth’s largest colony of Magellanic penguins have enough to eat by creating a marine protected reserve, with regulations on fishing, where penguins forage while raising small chicks.”
“Increasing storminess bodes ill not only for Magellanic penguins but for many other species,” the study’s authors conclude.
“A chick standing in a partly flooded burrow manages to keep its down dry.”
Image via: D. Boersma, University of Washington