The Antarctic penguins are advancing their breeding season by up to a month, and this drastic change is concerning scientists.
This is indicated by a new study conducted on different species, which blames climate change and the increase in global temperatures for these changes in the life habits of the fauna.
According to the analysis, dozens of colonies of three different species arrived at their nesting areas up to 24 days earlier than a decade ago.
This is an unprecedented transformation in the reproductive behavior of these birds, sentinels of the Antarctic ecosystem.
The study, published in Journal of Animal Ecology, revealed the phenomenon after analyzing data from 77 video cameras installed in 37 colonies.
In particular, researchers recorded that Adélie, chinstrap, and gentoo penguins significantly modified their arrival patterns at breeding sites, advancing the breeding season.
The average advancement reached two weeks, although some gentoo penguin populations advanced by almost an entire month.
A thermometer reveals the cause of the change in the penguins’ breeding season
The trap cameras deployed since 2011 incorporated thermometers that recorded the temperature in each shot.
This design allowed scientists to establish a direct correlation between the thermal increase and the reproductive advancement.
“Studying the oceans is a very difficult task, and in Antarctica logistically impossible due to the amount of ice,” explained Ignacio Juárez, a researcher at the University of Oxford and the first author of the work.
The data showed that since August, temperatures have risen rapidly each year.
In October and November, crucial months for the penguins’ breeding season, the increase reached 0.41º per year.
In particular, the warming in the colonies was up to four times greater than in the rest of Antarctica, a key element that altered the penguins’ breeding season.
Three species of penguins with the same pattern
The Adélie penguins arrived first, around October 15, advancing their arrival by one day per year.
Then, the chinstrap species appeared around October 20, two weeks earlier than in previous years.
Finally, the gentoo penguins arrived approximately on November 1, with an average advancement of 16 days since the start of monitoring.
“Once you see the penguins in the nest and they no longer move, that’s the day we say the breeding season has started,” detailed Juárez.
In addition to the arrival of the penguins, the researcher noted that all subsequent milestones of the breeding season—laying, hatching, and rearing—also advanced proportionally.
It should be noted that the 37 colonies studied cover practically the entire geographic range of these three species, making the finding a continental-scale phenomenon.
The consequences of the advancement of the penguins’ breeding season are still unknown
Scientists have not yet determined whether this reproductive advancement represents an adaptation or simply a forced response to climate change. The distinction is crucial to understanding the ecological implications of the phenomenon.
Specialists also considered that the accelerated melting interferes with the annual bloom of microalgae, the base of the Antarctic food chain.
This process also affects the krill consumed by penguins and, subsequently, by orcas and leopard seals, which can affect their habits.
“Since penguins are considered an indicator of climate change, the results of this study have implications for species worldwide,” highlighted Fiona Jones, co-author and researcher at Oxford.
The recorded advancement is the largest documented among birds and one of the most extreme among all living beings.
“We need more monitoring to understand if this record advancement in the penguins’ breeding season is affecting their reproductive success,” concluded Jones.
