Australian BirdLife magazine

The private life of penguins

The private life of penguins | Wednesday, 18 January 2023

  • Estimated reading time 5 min

The private life of penguins

Itinerant penguins from across the Southern Ocean are often spotted on Australia’s southern beaches in late summer and early autumn. John Peter uncovers why these motley, moulting seabirds pay us a visit. 

This story originally ran in our March 2020 issue. To receive our Australian BirdLife magazine, become a member today.

Somewhere in southern Australia over the past few weeks, a beachgoer has unexpectedly stumbled across a lonely figure standing forlornly on the sand, or huddled among some boulders, or sheltering on a ledge a little way up a cliff. That solitary figure is a vagrant penguin.

At this time of year, a penguin could turn up just about anywhere along Australia’s southern coastline. Only one species of penguin, the familiar Little Penguin, nests on our shores, but they’re here all the time. However, various other species—larger penguins with bright-yellow crests: Rockhopper (both Northern and Southern), Royal, Macaroni, Fiordland, Snares and Erect-crested Penguins, each originating from subantarctic islands—have all been recorded as vagrants along Australia’s southern coastline, often arriving in February and lingering till March.

Southern Rockhopper Penguins sometimes make their way to Australian beaches to hole up over the month-long moulting period when they cannot enter the water.
Southern Rockhopper Penguins sometimes make their way to Australian beaches to hole up over the month-long moulting period when they cannot enter the water. Photographed by Andrew Silcocks

These penguins might be seen on beaches anywhere from Western Australia to Victoria and Tasmania. In south-eastern Australia, a penguin on the beach will probably have originated from breeding colonies on subantarctic outcrops such as Macquarie Island or any of New Zealand’s outlying islands, while penguins found along Western Australia’s coast are more likely to have swum from Heard Island or other subantarctic islands thousands of kilometres to the south-west of Australia.

And if they’re here in February or March, they’re usually seeking refuge on a quiet beach to undergo a moult of their feathers.

All birds moult, and for most species it’s no big deal. The loss of a few tatty feathers here and there doesn’t drastically interfere with their lifestyles. They’re still able to fly (at least, most species are) and forage until the old plumage has been replaced. But it’s different for penguins.

Penguins moult their plumage once a year. Their feathers become worn and ragged between moults, losing the special qualities that penguins rely on—warmth and waterproofing.

Because penguins live in cold-water environments, keeping warm is high on their list of priorities. If a penguin went for a swim while moulting, the cold water would leak into the gaps between its missing feathers, flooding the tiny air pockets that occur between the plumage and the bird’s skin. It’s this layer of air that provides insulation, keeping the penguin warm, so when it’s breached by water, the all-important insulating properties are lost, and so are the waterproofing properties. This would cause the bird to quickly become both hypothermic and waterlogged—a life-threatening situation when you live in the Southern Ocean.

Because they can’t swim during the month or so it takes to replace their plumage, it’s essential for penguins to spend this period on dry land. That’s why they sometimes occur on Australia’s seashores at this time of year.

Before they moult, penguins feed voraciously to build up sufficient energy reserves to sustain them through the moulting period, when they’re forced to refrain from foraging for three or four weeks, due to the thermal/waterproofing issues that prevent them taking to the water.

Australia’s common penguin, the Little Penguin, usually retreats to burrows to moult, but most other species of penguins don’t, and haul themselves up onto a shore somewhere to moult in the open air. Most species of penguins moult in the subantarctic. However, recent radio-tracking studies have shown that penguins’ foraging expeditions are remarkably extensive, and some inevitably end up too far away to return to their usual haunts to moult. Instead, they look for the nearest available coast, and so each year a few waddle onto Australian beaches.

When moulting, penguins are generally quiet, as they need to conserve their energy. This strategy is fine on an isolated beach where they can mind their own business, but it’s a different story when they choose a popular stretch of coastline, where they’re confronted by all manner of unfamiliar threats—particularly unleashed dogs and curious onlookers.

People usually think a penguin standing quietly on the beach needs their help. If it’s during winter, a beached penguin is probably sick or exhausted and almost certainly requires assistance. However, in February or March, they’re usually moulting, and just want to be left alone.

A pair of Royal Penguins
A pair of Royal Penguins. Photographed by: Brian Jones

Nevertheless, every year, penguins are taken into the temporary care of zoos or wildlife rehabilitators—the best option if there are (or are likely to be) dogs on the beach, as even mild-mannered pooches readily kill penguins. However, there are instances of ‘helpful’ people returning moulting penguins to the sea—exactly what they were trying to avoid! Even by approaching a penguin you’ll send its stress levels soaring, so if you find a moulting penguin, stay a good distance from it (and, of course, keep Fido away too). If it’s moulting on an isolated beach, safe from canine or human interference, leave it alone, but if there’s any doubt, seek advice from the local Conservation Department or wildlife carer.

This time of year is a key period when penguins are vulnerable. If they can survive their time moulting on Australia’s beaches, by the end of March they’ll have headed back home—to face an entirely different set of challenges…

This story originally ran in our March 2020 issue. To receive our Australian BirdLife magazine, become a member today.