Vital Statistics
- Classification: Family Spheniscidae (penguins)
- Distribution: New Zealand and southern Australia (between Coffs
Harbour, New South Wales and Perth, Western Australia)
- Identification: Blue-grey back and head and creamy white front
and neck
- Average weight: 1.1kg, Males are on average 150g heavier than
females
- Average lifespan: 6.5 years
- Oldest recorded: 22 years
Diet
Little Penguins have a diverse diet and different colonies have
different preferences, depending on what is available locally. The
major prey species for Phillip Island penguins are pilchards (Sardinops
neopilchardus) and anchovies (Engraulis australis).
Prior to the pilchard population crash in 1995 large schools of
pilchards arrived in PPB around April/May, and large numbers of
adult Phillip Island penguins are also known to enter the Bay at
that time. It is thought St Kilda Penguins
have a similar diet to their Phillip Island cousins. However, a
2004 study by Phillip Island penguin researchers found anchovy to
be 95% of the St Kilda penguin diet. St Kilda is in close proximity
to the Yarra River estuary which is regarded as Victoria’s
major spawning area for anchovies.
Adult anchovies never grow too large for a penguin to swallow.
As a result, provided anchovy stocks remain healthy, the St Kilda
penguins would generally have a source of food locally available
all year round.
Radio-Tracking Study
In addition to the Penguin Study Group's ongoing twice-monthly
study, a radio-tracking study was conducted in 1993-94 by Mark Collins,
a scientist based at the Phillip Island Penguin Reserve. The aim
of the study was to track where and how far Victorian Little Penguins
travel in their search for food.
The study tracked the penguins' movements by using tiny radio-transmitters
attached to their backs. It was conducted through four seasons,
winter (June), when birds were feeding, September (when penguins
were incubating eggs), November (when penguins were feeding chicks),
and January (to track the fledging chicks' movements).
The data collected has permitted study and comparison of the foraging
and feeding habits of Little Penguins from both the St Kilda and
Phillip Island colonies.
Figure 1 Phillip Island penguins travel long distances to forage
(up to 100 km), whereas St Kilda penguins tend not to venture more
than 20 km because of a good local food supply. This map shows the
foraging movements of penguins from St Kilda and Phillip Island
in June and July 1993 as determined by radio tracking.
From the article entitled 'Urban Penguins' by Mike Cullen, Neil
Blake and Mark Bickham, which appeared in Nature Australia magazine
Winter 1996 Vol 25 No 5. Reproduced with permission from Nature
Australia magazine.
Subscriptions to Nature Australia are available through the Australian
Museum or call 1800 028 558 (free call within Australia). |
 |
Breeding
The Little Penguin matures at 2 or 3 years. It was always thought
that penguins mated for life, however studies of the St Kilda penguins
indicate otherwise. Our current understanding is that St Kilda's
penguins may change partners each year or even within a season.
Others stay with the same partner at the same nest from year to
year.
In the St Kilda colony egg-laying has been recorded from as early
as May through to December. Brood numbers peak in November, which
is the height of the breeding season. Early breeding may be precipitated
by exceptional abundance of anchovies and also by sea surface temperature.
Due to the fact that anchovy (penguin prey) can be taken all year
round it is not exceptional for St Kilda penguins to raise more
than one brood per season. The female lays two eggs and shares the
task of incubation with the male.
Penguin chicks hatch covered in a fine downy coat. After two weeks
the fine down is supplemented by a thicker, warmer down coat. At
about six weeks the penguin chicks start to grow adult (blue) feathers.
By the time they reach ten weeks old the penguin chicks have a complete
coat of adult feathers, which enables them to "fledge"
- go to sea and live independent of their parents.
St Kilda fledging chicks are heavier than their Phillip Island
cousins, which improves their chances of survival to breeding age.
Little Penguin chicks grow at an extraordinary rate at one month
old they have reached adult weight. To sustain this growth, both
parents have to return with food almost daily.
Biology
The Little or Fairy Penguin (Eudyptula minor) is the smallest member
of the Spheniscidae (penguin) family. It is a warm-blooded aquatic
animal.
It literally 'flies' under water thanks to its short wings modifying
into paddles and short legs at the rear of its body and is capable
of staying at sea for a month or more at a time. It will range over
many hundreds of kilometres to find sufficient food to trigger the
right body condition for breeding.
Penguins become sexually mature at 2 or 3 years of age and they
come ashore primarily to breed and moult. Little Penguins dig burrows
on islands or at the bases of cliffs, where they are safe from land-based
predators (like foxes). The St Kilda penguins find their shelter
between the rocks instead of digging burrows.
They come ashore at night and when staying on land during the day
remain hidden. Once they find a place to breed, they will usually
return there for life, although the ‘new’ colony of
St Kilda proves this is not always the case.
In the months just prior to the moult a penguin increases to one
and a half times its normal weight. This is so it has plenty of
reserves to survive the moulting season, when it is unable to leave
the shore, swim or feed. They are restricted to sitting ashore in
their nests and waiting for their new feathers to grow.
Differences Between St Kilda and Phillip Island Penguins
St Kilda Penguins
- Longer breeding season (May-December)
- Double the hatching rate
- Heavier chicks (heaviest recorded 1.3kg)
- Travel shorter distances for food maximum 10-20 km per day)
- Longer life span
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