The study, published Thursday in the British Ecological Society journal, assessed penguin breeding in artificial nests and in natural nests at eight major colonies across South Africa.

However, the researchers had also hoped their study would establish one artificial nest design that would suit all colonies — but found this wasn’t the case.

“Nature is never simple,” lead researcher Lorien Pichegru, from South Africa’s Nelson Mandela University, said in an interview, explaining that while fiberglass nests worked well in some cases, the devices became too hot and were “cooking” some of the penguin eggs in certain colonies with no shade or vegetation like Bird Island.

On Bird Island, where there are no mammal predators, cement nests “worked the best, being open on both sides allowing for air flow and natural cooling, but would provide poor protection against predators,” she explained.

Wooden boxes were the best performing nests on Robben Island, while ceramic nests had the highest egg and chick survival at Boulders Beach, the study added.

Pichegru noted that the results showed each penguin colony faced different threats due to their varying environments.

“The conclusions were colony specific,” she said. “Every colony manager must now find the right nests for their colony.”

South Africa turned to artificial nests to boost breeding some 30 years ago as numbers of the penguins rapidly declined. Pichegru said that researchers redesigned some of the devices around four years ago — in the hope they would yield better results than ever before.

And why do conservationists use artificial nests in the first place?

Natural African penguin nests were historically created using burrows dug into accumulated bird droppings known as guano, Pichegru said. However, the nests were largely removed by humans in the 1800s and 1900s due to the practice of harvesting guano, which was used for fertilizer.

As a result, the penguins were — and still are — forced to breed in open nests without protection from the sun. During heat waves as they seek to cool down at sea, the penguins leave eggs and chicks unattended, making them vulnerable to predators like kelp gulls.

“There’s so few left and there’s so little guano left there’s not enough for penguins to breed in those natural areas,” Pichegru said, adding that if there was more guano and more natural penguins nests, these would likely boost penguin breeding efforts more than the artificial devices.

The African penguin population has declined by 90 percent in the last 70 years. “They’re really not doing well,” Pichegru said, adding that it is likely that the status of the penguins will soon be downgraded to “critically endangered.”

Researchers estimate that at present, the country has less than 10,000 breeding pairs left.

Even as the study suggests artificial nests help boost populations, researchers caution that far more needs to be done to save the species.

Poor food availability is driving the species’ decline — the penguins feed on sardines and anchovies and, because they cannot fly, are limited to how far they can hunt for food. “Biologically meaningful fishing exclusion zones around their major colonies are urgently needed,” Pichegru said, adding that other factors contributing to a recent decline in rates include oil spills, underwater noise pollution and climate change.

And the spread of a deadly form of avian influenza has torn through many bird populations around the world, including African penguins.

Pichegru said that throughout the study the researchers were “very hopeful” that the results would show the nests, including their redesigns, were working, and that they were doing “absolutely everything” they can to save the black-and-white-bellied birds.

Aside from monitoring the use of artificial nests, Pichegru said that rehabilitation services are key. She is part of a team that has been collecting abandoned chicks and eggs for about 10 years, hand-rearing the birds in rehabilitation centers and releasing them.

Dino Grandoni contributed to this report.