Massive death of penguins due to 2019 heat wave, says study

Extreme heat events could have deadly effects on people and wildlife, according to a new study, as revealed by a 2019 heat wave that killed hundreds of penguins in Argentina.

At least 354 penguins were killed by a heat wave when temperatures soared to 111.2 degrees Fahrenheit (44 Celsius) on January 19, 2019, in Punta Tombo, Argentina’s Chubut Province, one of the largest breeding colonies for Magellanic penguins .

“This extreme event occurred near the end of the Magellanic penguin’s breeding season, so it killed a large number of adults, as well as chicks,” said study co-author Katie Holt, a study co-authored in the journal. ornithological applications,

Holt is a doctoral student in biology at the University of Washington, having sent research teams to Punta Tombo since 1982 to study the effects of rising temperatures on penguins. Summer temperatures typically range from less than 50K Fahrenheit to over 100F. In 2018, a team recorded a temperature of 109.4 Fahrenheit in the shadows.

Two dead Magellanic penguins in ‘heat-relief’ pose are seen in Punta Tombo, Argentina.
Katie Holt/University of Washington

“This is the first time we have recorded a mass death rate linked to extreme temperatures in Punta Tombo,” Holt said of the 2019 penguin deaths.

A similar phenomenon in North America has shown that extreme heat can wreak havoc on humans.

On June 28, 2021, temperatures reached 108 Fahrenheit in Seattle, Washington, while the village of Litton in British Columbia, Canada, experienced the nation’s highest temperature of 121.3 Fahrenheit the next day, before the city was devastated by wildfires. Brought on by a heat wave. In this 1,400 people were killed.

The January 2019 incident in Punta Tombo affected penguin adults and chicks differently. According to the necrosis conducted by the researchers, 264 adult penguins – about three-quarters of the total – probably died due to dehydration. Of the dead adult penguins, 27 percent were found on routes leading from the breeding colony to the seashore where they could obtain water. Penguins have glands that filter salt from seawater.

penguin feeds chick
An adult Magellanic penguin feeds on a chick while another adult watches it.
Natasha Gonaris / University of Washington

The journey from breeding colonies to the sea can be as long as 3,280 feet, with an adult Magellanic penguin taking about 40 minutes. Team members found dead adult penguins on their stomachs, with their mouths open and legs and flippers extended in a normal cooling-off posture.

“Any mass deaths like this are a matter of concern,” Holt said. “But what worries most about heat-hom mortality is that it has the potential to kill too many adults.” Because they can live 30 years or more, adult penguins can breed many chicks, she said.

The team found that eight out of 10 deceased adults were males, perhaps a reflection of a 3 to 1 ratio of males to females rather than differences in survival by gender. The team’s research shows that this one-sided ratio has increased over time: adult females returning to Punta Tombo are few, probably because they are not getting enough food before they go ashore to breed. This may be the reason for the decline in penguin colony size since the 1980s.

The remaining 90 were dead penguin chicks. According to the study, they probably did not because of dehydration or lack of food, but because their small bodies and full stomachs did not allow them to adequately regulate their body heat.

Magellanic Penguins, Punta Tombo National Reserve
Magellanic penguins walk along a wire fence in Punta Clara, about 18 km from Punta Tombo National Reserve in Chubut Province, Argentina, on December 5, 2021.
Getty Images/Daniel Feldman/AFP

Different regions of Punta Tombo showed different responses to heat during the spring and summer breeding seasons of the Southern Hemisphere. In the center, about 5 percent of adult penguins died, but in other areas there were little or no deaths. Access to the ocean, response to the microclimate and individual health factors may have influenced their survival. Past mass mortality was mainly due to destructive rain storms, which killed the chicks. One year, the storm killed half of the recently born chicks. But the 2019 heat event, Holt said, causes concern because it affects reproductive adults.

As extreme weather events and rising temperatures are expected to continue globally, the die-off at Punta Tombo allowed the team to record the ways that some species may have adapted to climate change.

“Penguins may have the ability to cope like relocating breeding sites,” Holt said. “But it will take time to test whether those adaptations are effective.

This story was provided to Greeley Tribune zenger news,