Image: Researcher holding a Magellanic chick with feather-loss disorder. Credit: Jeffrey Smith, MCS

'Naked' chicks are suddenly appearing in penguin colonies in South Africa and Argentina, leaving scientists perplexed.

The bald penguin chicks have a condition called feather-loss disorder. Although all penguins are born with downy feathers, some chicks inexplicably 'moult' their down before their adult feathers arrive, leaving them temporarily bald.

To try and find out why this is happening, scientists at the Wildlife Conservation Society (WCS) and the University of Washington have joined forces with researchers at the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) at the Centro Nacional Patagà ³nico in Argentina.

Featherless chicks were first seen in African black-footed penguins at a rehabilitation centre in Cape Town in 2006. But when the team of scientists found bald chicks at four Magellanic penguin colonies along Argentina's coastline between 2007 and 2010, they realised that it might be a global problem.

They noticed that the featherless chicks grew more slowly than normal, took longer to get their adult feathers and were smaller in size and weight, probably because they use more energy to keep warm.

They also saw that the bald chicks behaved differently and stayed out longer in the hot midday sun rather than seeking shade as those with feathers did. This could mean that featherless chicks are more vulnerable to the elements and disease.

The scientists' biggest concern is this condition could spread to penguins living in colder regions, which may not survive without the much-needed insulation from their feathers.

''We need to learn how to stop the spread of feather-loss disorder to other species, as penguins already have problems with oil pollution and climate variation'', says Dee Boersma, biology professor at the University of Washington and head of WCS's Penguin Project, in a WCS press release. ''It's important to keep disease from being added to the list of threats they face.''

Their findings are published in the journal Waterbirds. Although they haven't yet pinpointed the cause, they are now looking into thyroid diseases, nutrient imbalances, genetics, and pathogens such as viruses.

Mariana Varese, Acting Director of WCS's Latin America and Caribbean Program, says, "More studies on this malady can help to identify the root cause, which in turn will help illuminate possible solutions.''