The mystery of penguin deaths: climate change threatens species survival

In July, some 2,000 Magellanic penguins were found on the beaches of Uruguay, dead with empty stomachs and “very emaciated” bodies.

“It’s death in the water,” Carmen Leisagoyen, an employee of Uruguay’s environment ministry, told AFP.

“Ninety percent are young specimens that arrive without fat reserves and with empty stomachs.”

The cause of the mass die-off is still unknown, but scientists fear that extreme climate change is contributing to the rapid population decline of the species.

Magellanic penguins (Spheniscus magellanicus) have been considered “near-threatened” by experts since 2004, and over the past 30 years it has become alarmingly common to find hundreds of these birds dead on the east coast of South America.

In 2010, for example, more than 550 penguins starved to death on the beaches of Brazil.

Two years later, another 745 penguins were found dead on the country’s coast.

Interestingly, the cause of mass deaths is not always the same.

In some years, the main threat can be related to rising temperatures, for example, in 2019 in Argentina, 354 penguins died from extreme heat while nesting.

In other years, the main cause may be hypothermia, storms or starvation.

It all depends on where these penguins are located during their migration.

Magellanic penguins nest in southern Argentina for most of the summer. In winter, however, they move north in search of food and warm water.

It is not uncommon for some young to die during this journey, but recent mortality has gotten out of hand.

This year, experts speculate that a subtropical cyclone off the coast of Uruguay may have weakened an already depleted population. Dead seabirds, turtles and sea lions have also been found in surrounding areas, supporting this theory.

Dead penguins scattered on a beach in Uruguay on July 20, 2023. (Maldonado Authority of Uruguay)

Dead birds on the beaches of Uruguay have tested negative for bird flu, but their stomachs have been empty for days and their feathers are surprisingly devoid of the fat that repels water and insulates the birds from cold temperatures.

The combined factors may have been too much for many young penguins to bear.

“Food shortages due to overexploitation of fisheries in the South Atlantic region and the effects of climate change on ocean currents may be the causes of this sad event,” explains animal welfare organization SOS Rescate de Fauna Marina on Facebook.

“The hypothesis of a storm connection is also being considered. But in fact, the lack of energy is a factor that they could not survive the storm.”

Scientists have known that Magellanic penguins have been experiencing feeding difficulties since the 1990s, but little has been done in these years to ensure the sustainability of anchovies, sardines and other tasty snacks for penguins in this part of the world.

Overfishing is a key factor, but so are changing weather patterns due to climate change, which can alter the distribution of the main prey in the ocean.

In 2009, the number of breeding pairs of Magellanic penguins in Argentina had fallen from 300,000 in the 1990s to just 200,000.

If nothing changes, mass die-offs of this species could become an annual occurrence.

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