This has likely contributed to an overall decrease in the size of the colony since the late 1980s. Research by Boersma’s group shows that adult females are less likely to return to Punta Tombo to breed, likely because they have more trouble finding enough food in the open ocean outside the breeding season. The colony’s skewed sex ratio has grown over time. That likely reflects the high prevalence of male Magellanic penguins at Punta Tombo - roughly three males to every female - rather than a differential survivability in extreme heat.
If we’re losing large numbers of adults from a single event like this, that’s a major concern.”īased on examination of a subset of corpses, at least 8 out of 10 of the adults that died were males. Adult Magellanic penguins can live more than 30 years, so they typically have many opportunities to successfully raise chicks.
The population viability of long-lived seabirds - like Magellanic penguins - relies on long lifespans. “But what is most concerning about heat-death mortality is that it has the potential to kill a lot of adults. “Any mass die-off like this is a concern,” said Holt. The 2019 heat wave is a particular concern because it led to the loss of a large number of adults in a single event, according to Holt. UW researchers have documented past mass mortality events at Punta Tombo linked to severe rainstorms that killed primarily chicks, including one year where deluges killed 50% of the colony’s recently-hatched offspring. But other sections saw few or no fatalities, indicating that microclimates and access to the ocean, as well as individual health and nutrition, may have influenced survival rates. In the central section of the colony, about 5% of adults perished. Some sections of Punta Tombo, where thousands of Magellanic penguins gather to breed each austral spring and summer, fared worse than others. Dead adults were often found on their stomachs with their feet and flippers extended and mouth open, a common panting and cooling pose for Magellanic penguins. A journey from the colony to the ocean can stretch up to one kilometer and, at its longest, might take an adult Magellanic 40 minutes to complete. They found 27% of adult penguin corpses along paths heading out of the breeding colony to the ocean, where they could get a drink - penguins have glands that can filter salt out of the water. Nearly three-quarters of the penguins that died - 264 - were adults, many of which likely died of dehydration, based on postmortem analyses conducted by the UW researchers. 19 affected adults and chicks differently. In a past season, researchers had previously recorded a shade high of 43 C, or 109.4 F, but that older record was not associated with a mass die-off of penguins, according to Holt. Temperatures at the site during the breeding season typically rise from the 50s F to the low 100s F. 19 heat wave was the highest temperature the researchers have ever recorded at Punta Tombo, where UW teams have been studying Magellanic penguins since 1982 under co-author P. “It’s the first time we’ve recorded a mass mortality event at Punta Tombo connected to extreme temperatures.” “This extreme event fell near the tail end of the breeding season for Magellanic penguins, so it killed a large number of adults, as well as chicks,” said lead author Katie Holt, a UW doctoral student in biology. 4 in the journal Ornithological Applications, the extreme heat wave killed at least 354 penguins, based on a search for bodies by UW researchers in the days following the record high temperature. As the team reports in a paper published Jan. 19, temperatures at the site in Punta Tombo, on Argentina’s southern coast, spiked to 44 C, or 111.2 F, and that was in the shade. In 2019, University of Washington researchers witnessed this in Argentina at one of the world’s largest breeding colonies for Magellanic penguins. On June 28, Seattle reached 108 F - an all-time high - while the village of Lytton in British Columbia recorded Canada’s highest-ever temperature of 121.3 F on June 29, the day before it was destroyed by a heat-triggered wildfire.Ĭlimate change is expected to bring more such extreme heat events globally, with far-reaching consequences not just for humans, but for wildlife and ecosystems. Newswise - In June 2021, an unprecedented heat wave hit the Pacific Northwest and Canada, killing an estimated 1,400 people.
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