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British Antarctic Territory – Life Cycle of the Gentoo Penguin

Gentoo penguins are the third largest species of penguin, after the
emperor and king penguin. They reach heights of between 75 – 90cms and
weigh between 5-6.5kgs, males being slightly. They belong to the genus
Pygoscelis, which includes the Adélie and chinstrap penguin. Gentoo are
black and white birds and can be easily distinguished from other
penguins by their bright orange-red bill and the white patches above
their eyes, which usually meet across the crown. They have brown eyes,
yellow-orange feet and the most prominent tail of all penguins. As the
gentoo walks its tail sweeps from side to side, hence the name
Pygoscelis, which means ‘brush-tailed’.

Gentoos are the most northerly of the 4 Antarctic species. They have a
circumpolar distribution, breeding on sub-Antarctic islands and the
Antarctic Peninsula (46-65°S). They have a life expectancy of up to 20
years and the total breeding population is estimated to be 314,000
pairs. Breeding colonies rarely comprise more than a few hundred pairs,
much smaller than other similar penguins. Unlike other species that nest
alongside them they wait until the sea ice has retreated before heading
for the nesting grounds, so are the last to arrive.

Each pair will set about the task of constructing nests from stones,
tussock grass, old feathers and moss. Nests can contain as many as 1,700
individual stones and stone theft is common. If a gentoo has an
opportunity to peck another penguin it will, so nests tend to be spaced
slightly out of reach of each other. Into these nests they lay two
spherical white eggs which are incubated by both the male and female for
up to 39 days. If necessary they are the only penguins that are able to
lay a replacement clutch of 2 eggs. Egg-laying is usually completed by
late October with both parents sharing the incubation duties for the
next 34-36 days.

Hatching is followed by 25-35 days when the chicks are brooded and
guarded by their parents. After this time, the chicks are then large
enough to become mobile and form into crèches. They are fed daily by
both parents until eventually they fledge at 80-100 days.

Gentoo penguins reach sexual maturity at the age of two years, although
most start breeding at 3–4 years. They remain faithful to both their
nesting sites and their breeding partners, with many forming
long-lasting pair bonds.

On land the gentoo walks with a humorous waddle, but once in the water
they are the fastest underwater swimming bird. They can reach speeds of
up to 36km per hour (with an average of 6.5km per hour) and are capable
of diving to depths of 170m in pursuit of prey. They mainly feed on
krill (50%) and fish (30%) with squid and other crustaceans as available
making up the remaining 20%. They tend to prefer feeding inshore near to
the breeding colony during daylight with most achieving depths of up to
50m. At sea they are subject to predation by leopard seals, sea lions
and orcas, whilst skuas prey on eggs and chicks.

Base A Port Lockroy is a designated Historic Site and Monument under the
Antarctic Treaty and is now a museum and the British Antarctic
Territory’s main post office managed by the UK Antarctic Heritage Trust
(UKAHT). It is also known for its gentoo penguins, who return to the
island each year to build their pebble nests, lay their eggs and raise
their chicks during the short Antarctic summer months. It is believed
the gentoos first begun nesting on the island in 1985. There are now an
estimated 3000 gentoo penguins that return to Goudier Island each year
to breed.

The UKAHT, through its team on the ground, ensures that everything
possible is done to minimise any tourism impact on them. Part of Goudier
Island is cordoned off as a 'Penguin Control Colony' where visitors are
not permitted. This allows the UKAHT team to monitor and compare the
population size, distribution and breeding success of the 'control
colony', who have very little contact with humans, with the other
breeding penguins on the island, who are in close proximity both to the
staff and visitors. Monitoring the penguins is carried out three times a
year and the results are forwarded to the British Antarctic Survey.
Evaluation of the statistics (records start in 1996) show that there has
been no discernible impact from tourism on the gentoo penguins at Port

Technical details:

Designer Bee Design

Printer (sheet stamps) BDT International Security Printing Ltd

Printer (reel stamps) Lowe-Martin

Process Lithography

Perforation 14 per 2cms

Stamp size 30.56 x 38mm

Reel stamp size 25.3mm x 20.8mm (self-adhesive).

Sheet Layout 10

Release date Expected mid-November, 2016

Production Co-ordination Creative Direction (Worldwide) Ltd


Egg © UKAHT, Florence Kuyper

Chick © UKAHT, Claire Murphy

Feeding: © UKAHT, Eleanor Land

Adult with chicks: © UKAHT, Helen Annan

Fledgling: © UKAHT, Claire Murphy

Adult: © UKAHT, Helen Annan

FDC: © UKAHT, Claire Murphy

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