Research has discovered a new killer of baby penguin chicks: climate change. Studies in Punto Tombo on the Atlantic coast of Argentina have shown a recent hike in deaths amongst Magellanic penguin chicks. The cause of this increase is due to fluctuating weather systems and severe storms hitting the nesting grounds. Every year, 200,000 penguin breeding pairs call the area home from February to September.
Baby penguins are already exposed to the dangers of starvation and predation when they are just out of the womb. On average, 65 percent die before they are two months old. Conservation biologist Dee Boersma has been watching the penguins at Punto Tombo for going on 28 years. In the course of her study, she noticed that penguin populations were shrinking. Several penguins were tagged electronically and she saw that they were going further out for food. This lead to her initial belief that the birds were dying off due to scarcer food in the region. The squid that were the penguin’s main diet were staying further out, making the hunt for them that much more difficult. Sea surface temperatures in the area had risen a few degrees, another side effect of climate change, which kept the squid in deeper ocean areas.
Then in 2010, Boersma noticed the real problem. Punto Tombo had been getting significantly wetter in recent time with an unprecedented amount of heavy rain storms. Previously the region had four inches of rain on average during the penguin breeding season. Hypothermia was now the major cause of death amongst baby chicks, outstripping all previous percentages of starvation and predators combined. For animals that live in water, this seems implausible, but penguin chicks only develop their heavy, waterproof coats when they are over 40 days old. Before that, they have a soft, downy plumage, perfect for the cold, dry climate that they have lived in for generations. Their fine feathers trap air and keep them insulated. The wetter climate in the region has changed that. If their down becomes wet, then they lose heat very quickly.
Warmer weather has also been a factor, with extreme heat listed as another penguin killer. In addition, warm weather equals more moisture rising off the Atlantic thus producing wetter storms. The warmer climate is a result of the presence of increasing levels of greenhouse gases in the atmosphere. Boersma notes that the dramatic increase in change has left baby penguins ill-prepared for life ahead of them. Younger Magellanic chicks have a slightly better chance of survival during the storms as they remain hidden under the wings of the parents. Those that were between nine and 23 days old are the least likely to survive.
Boersma states that climate change has resulted in a new environment that baby penguins are not equipped to deal with. New killers like hypothermia and heat have lessened the poor chance that the chicks had to begin with. Boersma published her study in Plos One this month.
By Sara Watson