South America Update – November 2018

Dear PenguinPromises

The penguins have arrived back home in the colony after their winter
migration. As usual the males arrived about 10 days before the females. The
pairs split up during the winter migration because it is impossible for the
couple to remain together out in the open ocean. The waves make it difficult
to see very far, and the penguins all look much the same at a distance. The
first time one of the penguins chased a fish they would loose contact with
each other, so they don’t even try. They just go their separate ways and
meet up again back at the nest at the end of the winter migration.

Magellanic penguins remain together for life, and the pairs meet up again
back at the nest each October, ready for another season of egg-laying and
chick-rearing. Like any gentleman, the males do not keep the ladies waiting
for such an important date.

After reuniting in mid October, the pair rebuilt the nest using a different
part of ‘their’ bush for the new nest. The old nest lining becomes
contaminated with guano and fleas that lie dormant over the winter, awaiting
the return of their host, so moving the nest a couple of yards / metres is
cleaner and healthier. There are now two eggs in the nest, and I attach a
new photo of your penguin incubating the recently laid eggs.

The eggs are about twice the size of chicken eggs, and they take about seven
weeks to hatch, so your penguin has a lot of work to do between now and
December. The pair take turns incubating the eggs so as to keep the eggs
warm. A tiny baby penguin is growing inside each egg and the eggs have to be
kept warm all the time for the eggs to hatch successfully..

The Straits of Magellan is an important area for penguins and other
wildlife. For that reason the whole of the Straits of Magellan has a ban on
large scale commercial fishing, so the penguins’ food supply is protected
here and the penguins have increased over recent years..

With about 130,000 penguins living here in the colony, it is very noisy. The
penguins bray like donkeys, and Magellanic penguins are often called
‘Jackass penguins’ because of their strange call. It is a nickname shared by
other closely related penguins that have a similar call, such as African
penguins. The braying of the penguins continues day and night. Penguins are
very sociable and like living close together.

Whilst they are incubating the eggs the penguins have no access to food. The
eggs have to be kept warm for about seven weeks, and the penguins cannot go
without food for that long. That is why penguins always breed in pairs,
because it is not possible for one penguin to do all the work alone.

One penguin stays in the nest keeping the eggs warm, whilst the other goes
out to sea to catch fish. They swap over every two or three days, so that
both penguins take turns going out to sea to feed.

Books and TV programs quote all kinds of numbers as to how long the penguins
wait for their partner to return to the nest. The reality is that it changes
between species, and also between colonies, depending on how close fish
stocks are to the colony. What I can say for sure is that two to three days
is the average here for our penguins.

When we began our work here in 2003, one of the first factors that we
studied was how frequently the pairs change over nesting duties. This
information is important in understanding how changes in food availability
can affect nesting failure, which in turn is important for understanding and
protecting the colony as a whole.

To gather this information we used large non-toxic crayons of the type sold
to farmers for marking sheep and cattle. Being non-toxic they do not harm
the penguins, even if swallowed, and they wash off when the penguins go out
to sea. The crayons were mounted on the end of a pole so that we could make
a small mark on the penguin’s chest when the penguin was lying over the
eggs.

We always mark the upper chest area because this is easy to reach without
disturbing the penguin, and also easy to view each day to check whether or
not the penguins have changed over. In addition, the penguins cannot reach
this area to preen, so the coloured mark remains throughout the time that
the penguin is in the nest. By marking one of the pair with a spot of red,
and the other with a spot of blue, we are able to see exactly how many days
pass between the ‘changing of the guard’.

The coloured crayon system is simple but it works very well and does not
disturb the penguins at all, which barely notice being touched by a thin
pole. The results are also backed up by another less scientific observation.
The penguins recently back in the nest are nice and white, but as the days
pass by they gradually become grubbier in colour as a result of the dust
blowing around the colony. After going out to sea they return nice and clean
again.

The average is about 2 to 3 days, but sometimes it is longer. If it gets to
about 6 or 7 days without a partner returning, the penguin on the eggs
abandons the nest. This does not happen very often, but clearly a week is
about as long as Magellanic penguins can go without food at this time of
year. This shows how important it is to protect fish stocks close to penguin
colonies, for example from commercial fishing.

Later in the year, these same penguins will go for three or four weeks
without food when they moult their feathers, but the difference is that they
prepare for that moult by feeding out at sea for almost a month, building up
their body fat reserves in order to prepare for such a long period without
food. At this time of year the penguins have not prepared for a long fast,
and a week is about as long as they can go without food.

November 2018 update

In most cases the ‘lost’ partner does eventually return to the nest, usually
to find the nest empty because the eggs have been stolen by gulls and the
partner has gone to sea. It is not clear whether these ‘lost’ penguins have
bad luck finding fish, or whether they simply loose track of time.
Thankfully it does not happen very often, and seems to occur mainly with
young inexperienced pairs. Whether their partner forgives them the following
year is unclear.

The weather here can be really horrible, with heavy rain and very strong
winds. The day that we took the new photo of your penguin it was very sunny
with no wind at all, but that is not normal for here. We are now in our
spring and the weather is very changeable. Occasional there is no wind and
the sun is really strong due to the lack of ozone this far south, other days
there is snow, but most of the time it is just windy. Patagonia is famous
for its strong wind.

There are lots of seagulls here flying around the colony continually looking
to steal eggs from the nests. Penguins are much larger and stronger than the
seagulls, so the gulls never bother the penguins, but the gulls are sneaky.
As long as the penguins are careful and keep the eggs covered, the gulls
don’t go near the nest, but if a penguin leaves the nest unattended for just
a few minutes, a gull will swoop down and fly off with an egg in its beak.

Although the penguins have to be careful with the eggs, so far the work is
very easy. All they have to do at the moment is lie over the eggs and doze.
The penguins don’t even have to stay awake. Just lying over the eggs is
enough, and when the weather is sunny, most of the penguins have their eyes
closed. The real work begins in December when the eggs hatch and then they
will have hungry chicks to feed. I will write to you again as soon as the
eggs hatch.

Best wishes,  Mike

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