Life has never been easy for just-hatched Magellanic penguins, but climate change is making it worse, according to a decades-long study of the largest breeding colony of the birds.

The chicks are already vulnerable to predation and starvation. Now, the study at Punta Tombo, Argentina, found that intense storms and warmer temperatures are increasingly taking a toll. "Rainfall is killing a lot of penguins, and so is heat," said P. Dee Boersma, a University of Washington scientist and lead author of the study. "And those are two new causes."

Climate scientists say more extreme weather, including wetter storms and more prolonged periods of heat and cold, is one result of a climate that is changing because of emissions of greenhouse gases in the atmosphere. While monitoring the penguin colony, Boersma and her colleagues also documented regional temperature changes and increases in the number of days with heavy rains.

The study, published online in PLoS ONE, is one of the first to show a direct effect of climate change on seabirds. Most studies have looked at how warming temperatures affect animals indirectly, by altering predation patterns or food supplies.

The colony at Punta Tombo, in a temperate and relatively dry region about midway along Argentina's coast, is home to about 200,000 breeding pairs of the penguins. For this study, the researchers compiled data on nearly 3,500 chicks that they tracked by checking nests once or twice a day throughout the six-month breeding season, which starts in September.

Typically, nearly two-thirds of hatchlings do not survive to leave the nest. But they found that heavy storms killed birds in 13 of the 28 years of the study. In two years, storms were responsible for most of the deaths. Extreme heat killed more hatchlings as well. "They didn't used to have to contend with this variability in the climate," Boersma said. "And they certainly didn't have to contend with all this rainfall."

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