'Naked' penguins baffle experts

Feather-loss disorder first seen in African penguins

April 2011: Researchers from the Wildlife Conservation Society, the University of Washington, and other groups are grappling with a wildlife mystery: Why are some penguin chicks losing their feathers?

Feather-loss disorder has also been observed in African penguins, which inhabit the coast and offshore islands of South Africa. Credit: Nola Parsons

The appearance of ‘naked' penguins - afflicted with what is known as feather-loss disorder - in penguin colonies on both sides of the South Atlantic in recent years has scientists puzzled as to what could be causing the condition.

‘Feather-loss disorders are uncommon in most bird species, and we need to conduct further study to determine the cause of the disorder and if this is in fact spreading to other penguin species,' said P. Dee Boersma of the Wildlife Conservation Society, who has conducted studies on Magellanic penguins for more than three decades.

No cause has yet been found
The disorder first emerged in Cape Town, South Africa in 2006, when researchers for the South African Foundation for the Conservation of Coastal Birds (SANCCOB) first observed the disorder in African (or black-footed) penguins at a rehabilitation centre. During that year, approximately 59 per cent of the penguin chicks at the facility lost their feathers, followed by 97 per cent of the chicks at the facility in 2007, and 20 per cent of the chicks in 2008. Chicks with feather-loss disorder, it was discovered, took longer to grow to a size deemed suitable for release into the wild. The chicks eventually began growing new feathers.

On the other side of the South Atlantic, researchers from Wildlife Conservation Society (WCS) observed feather-loss disorder in the chicks of wild Magellanic penguins, which are closely related to African penguins, for the first time in 2007 in four different study sites along Argentina's coastline. Researchers also noted that while feathered chicks sought out shade in the hot midday sun, featherless chicks remained in the sun's glare. Several of the chicks with feather-loss disorder died during the study.

‘The recent emergence of feather-loss disorder in wild bird populations suggests that the disorder is something new,' said Mariana Varese, of WCS. ‘More study of this malady can help identify the root cause, which in turn will help illuminate possible solutions.'

Boersma added: ‘We need to learn how to stop the spread of feather-loss disorder, as penguins already have problems with oil pollution and climate variation. It's important to keep disease from being added to the list of threats they face.'