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The Life Cycle of Penguins: Adults: Moulting
Some penguins return to their home colonies to moult while others will take up
residence somewhere quite different. One example is this King penguin who returns
every year to Campbell Island for his moult. Once penguins achieve their adult plumage, they do not change the pattern of it in any way during the moults. The pictures below of African Penguins were taken in successive seasons on Boulders Beach, so the birds must have moulted in between. Nevertheless, we were easily able to recognise the birds from the patterns of spots that had not changed in the slightest in the moults. Moulting is
extremely important to penguins as they need to maintain their feathers in tip top
condition at all times. The feathers come in two layers and serve two
purposes. The bottom layer of downy feathers provides thermal insulation by trapping
a layer of air close to the skin and helps keep the birds warm in the cold waters where
they fish and for the Antarctic species in the cold air where they breed. The top
layer of interlocking waterproof feathers keeps the cold water away from their skin and acts
like a dry diving suit so that they can easily survive in the very cold Antarctic and
sub-Antarctic waters. |
All penguins need to replace
their feathers each year. Adults generally do this after the breeding season.
Once their chicks have moulted into their own juvenile plumage the adults return to sea
for a few days to build up their own fat reserves and then come back ashore to
moult. The moult takes about three weeks and the birds can only stand around and
fast. This must be a particularly miserable time for penguins. Because they
are moulting they lose their waterproof coats and cannot enter the sea so they have to
face the elements and starve until their smart new set of feathers is ready. 
