Ceramic ‘igloos’ could keep African penguins cool and cozy

Ceramic ‘igloos’ could keep African penguins cool and cozy

This article was originally featured on Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

South African scientists discovered that ceramic nest boxes can protect endangered African penguins against climate change.

In the past, seabirds laid eggs in burrows that were dug into layers of centuries-old excrement. But in the 1800s, most of the guano was scraped up by traders and shipped to the United Kingdom as fertilizer. Many penguins have been nesting in open areas, exposing them to heatstroke, as well as their eggs and chicks, to predators and desiccation. Shaun Welman (Nelson Mandela University) is a zoologist who has seen penguins with their eyes closed, their heads down, and their beaks open in the scorching midday heat. He believes this is to protect their eggs.

Penguins can overheat easily on land because they evolved to heat in cold water. Penguins will often leave their nests to cool off in the ocean, but without proper burrows, this leaves eggs unprotected.

” We have now put this entire species at danger of extinction, primarily because of human greed and exploitation,” Welman states.

Since 1900, the African penguin population has fallen to a fraction of its former glory: a mere 48,000 birds, down from as many as three million.

Fortunately, a team consisting of conservationists and researchers working under the African Penguin Nest Project appears to have found a solution. Over the past four years, the team has designed and deployed more than 1,500 handmade ceramic nest boxes in five penguin colonies including Bird Island, located in Algoa Bay, an area that is home to nearly half of the world’s remaining African penguins.

Ceramic ‘igloos’ could keep African penguins cool and cozy
In South Africa, double-walled ceramic nests outperform cement and fiberglass models–as well as natural guano burrows–for keeping African penguins cool. Kevin Graham/African Penguin Nest Project

A new study coauthored by Welman shows that the ceramic design provides the best nests on Bird Island. The artificial nests are cooler than penguins’ guano burrows. Only a few of these still exist.

Welman and Lorien Pichegru (acting director of the Institute for Coastal and Marine Research, NMU) found that older cement nests get too hot. Inside, temperatures at times exceeded 40 degC and occasionally even 50 degC, putting eggs at risk of overheating. Pichegru has also found dangerously high temperatures in fiberglass-made artificial nests.

But, the new ceramic nests were made from two molded shells of gray fabric, soaked in a clay slurry, and fitted together to look almost like an igloo.

The ceramic nests remained around 1 degC lower than a penguin’s resting body temperature of 37.6 degC, while humidity stayed above a comfortable 70 percent. The nests were so effective, Welman says, that “if adults had to abandon nests for whatever reason, the eggs would never be at any risk of overheating.”

Even in milder conditions, the new nests can make a big difference. In a separate experiment, on a sunny 25 degC day, the African Penguin Nest Project team logged temperatures of nearly 51 degC on the ground outside a ceramic nest box and just 23 degC inside.

It was impossible to find a viable artificial nest soon enough, as it seems that African penguins are more sensitive than previously thought. On Bird Island, Welman and Pichegru saw birds panting in an effort to cool down in temperatures as low as 22 degC. Birds nesting in areas that are exposed to climate change will be more at risk.

Christina Hagen, BirdLife South Africa’s spokesperson, said that the results showed that ceramic nests could be a useful conservation tool. She says that it is crucial to find effective conservation solutions given the dire situation of the African penguin population.

The main threat to African penguins comes from overfishing of anchovy, sardines and other seabirds that are their favorite prey. Conservationists and scientists are urging the South African government not to allow commercial fishing in six African penguin breeding colonies. This will ensure that populations recover. Despite the fact that these efforts are not sufficient to protect the land from predators and rising temperatures, they may not be enough. Ceramic nests may be able to give these seabirds a fighting chance.

This article first appeared in Hakai Magazine, and is republished here with permission.

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