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Antarctic Penguins Face Early Breeding Dilemma as Temperatures Rise, Threatening Two Species with Extinction
WASHINGTON D.C. – A groundbreaking study reveals that rising temperatures in Antarctica are forcing penguin species to begin their breeding cycles significantly earlier, a shift that could spell doom for two beloved “tuxedoed” species by the century’s end.
Over the past decade, from 2012 to 2022, the breeding grounds of these iconic birds have seen a temperature increase of 5.4 degrees Fahrenheit (3 degrees Celsius). This rapid warming has prompted three distinct penguin species to start their reproductive process roughly two weeks earlier than in the preceding decade, according to research published in Tuesday’s Journal of Animal Ecology. This accelerated timeline is creating critical food shortages for young chicks.
“Penguins are altering their breeding times at an unprecedented rate, faster than any other vertebrate,” stated lead author Ignacio Juarez Martinez, a biologist at Oxford University in the United Kingdom. He emphasized the crucial need for breeding to align with periods of abundant resources, particularly food essential for the growth of their young.
To put this into perspective, scientists noted that a similar two-week shift in the life cycle of European great tits took 75 years, while these three penguin species have undergone the same change in just 10 years, explained study co-author Fiona Suttle, also an Oxford biologist.
Researchers meticulously monitored penguin breeding activity from 2011 to 2021 using remote-controlled cameras in dozens of colonies. Their findings indicate the fastest observed shift in the life cycle timing for any backboned animal. The three species in question, all “brush-tailed” for their distinctive dragging tails, include the wide-eyed Adelie, the black-striped chinstrap, and the agile gentoo.
Climate Change Creates Winners and Losers Among Penguin Populations
Suttle highlighted that climate change is creating a stark divide among these three penguin species, with critical implications for their survival due to intensified competition for food during a vital stage of their life cycle.
Adelie and chinstrap penguins, specializing in a diet primarily of krill, are facing increased pressure. In contrast, the gentoo, with its more varied diet, is emerging as a “winner.”
Historically, these species bred at different times, avoiding competition. However, the gentoo’s breeding has advanced more rapidly than the other two, leading to an overlap.
This presents a significant challenge as gentoos, which do not migrate as extensively, are more aggressive in securing food and nesting territories, according to Martinez and Suttle.
Suttle recounted personal observations of returning to colonies in October and November where Adelie nests once thrived, only to find them replaced by gentoo nests. This anecdotal evidence is strongly supported by the collected data.
“Chinstraps are experiencing a global decline,” Martinez warned. “Projections suggest they could face extinction before the end of the century at this current rate. Adelies are struggling significantly in the Antarctic Peninsula and are highly likely to become extinct from that region before the century’s close.”
Early Bird Dining Habits Lead to Ecological Problems
Martinez theorizes that the warming western Antarctic, the second-fastest heating region on Earth after the Arctic North Atlantic, results in less sea ice. This reduction in ice cover facilitates an earlier release of spores in the Antarctic spring, leading to an “incredible bloom of phytoplankton,” which forms the foundation of the marine food web vital for penguins. This phenomenon is occurring progressively earlier each year.
Compounding the issue for chinstraps and Adelies is not only heightened competition from gentoos due to warming and shifts in plankton and krill, but also an earlier start to commercial fishing, further depleting their food supply, Suttle added.
Michelle LaRue, a professor of Antarctic marine science at the University of Canterbury in New Zealand, who was not involved in the Oxford study, commented on the significance of these findings: “This shift in breeding timing is an intriguing indicator of change, and it’s now crucial to continue monitoring these penguin populations to assess if these changes are having detrimental impacts on their numbers.”
Public Affection for Penguins Fuels Scientific Research
With millions of images captured hourly by 77 cameras over a decade, scientists enlisted the public’s help through the Penguin Watch website to tag breeding activity.
“We’ve had over 9 million of our images annotated via Penguin Watch,” Suttle enthused. “A large part of that comes down to people’s immense love for penguins.
They are incredibly cute. They adorn all the Christmas cards.
People often remark, ‘Oh, they look like little waiters in tuxedos.'”
Suttle also highlighted the Adelies’ unique charm. “The Adelies, I think their personality goes along with it as well,” she said, noting “perhaps a kind of cheekiness about them – and this very cartoon-like eye that does look like it’s just been drawn on.”