One-Child Policy

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The erect-crested penguins are an odd and mysterious bunch.

The penguin species lives on remote islands hundreds of miles off the southern coast of New Zealand. It is considered endangered even though scientists haven’t thoroughly studied the species.

“No one knows virtually anything about them,” Lloyd Davis, a biologist and science communicator at New Zealand’s University of Otago, told the New York Times.

In 1998, Davis and his team visited the isolated Antipodes Islands to gather more information about the enigmatic birds.

Recently, they published a study based on those findings that underscore a strange – and ruthless – parenting behavior: Killing potential chicks.

At the time, the researchers monitored the creatures during their mating season, including observing their courtship, as well as egg-laying and incubation behaviors.

They explained that all species of crested penguins lay two eggs in a breeding season, a smaller first egg and a larger second egg. In other bird species, the smaller egg – and the last one to be laid – would usually serve as an “insurance policy” in case the other larger one dies.

But the erect-crested avian didn’t care about insurance: The team observed that all the smaller eggs died, either because they weren’t incubated or they rolled out of the nests or the parents shoved them away.

Even when Davis and his colleagues created protective rings around some nests, the small eggs were still neglected.

The authors aren’t exactly clear why the parent penguins do this, but they suggest that food scarcity forced the birds to adapt and reduce their brood size to one.

Still, Davis hopes that the study will bring more attention to the erect-crested penguins, which face numerous threats from global warming and the exploitation of the oceans by humans.