South America Update – September 2017

Dear PenguinPromises


The penguins have now left Brazil and are on their way home. We expect Promises

to arrive back in the nest sometime during October. After arriving home in the

colony a few days will be spent nest building, and then a couple of weeks later

the egg-laying will begin. As soon as the eggs have been laid we will send you

a photo of Promises in the nest. That will probably be during early November,

but the exact date is up to Promises.


We cannot take photos before the eggs have been laid, because if we tried to

do that some penguins would become upset and move to another location. Older

penguins are well used to having us visit their nest, but young penguins laying

eggs for the first time can become upset at having human visitors. Once the eggs

have been laid the penguins will not leave the nest, so it is safe to take the

photos. Whilst we are waiting for Promises to return, I would like to share with

you the results of last year’s research.


Beginning with our colony in Argentina, during our first season working at Cabo

Virgenes during the summer of 2003/04, breeding success was very low. Only 10%

of all eggs laid resulted in a healthy chick leaving the colony. Since each pair

lays two eggs, that means that the breeding success was 0.2 chicks per nest.

That is to say that 0.2 chicks were raised in each nest, which equals only one

chick for every 5 nests.


That was really bad, and it was clear that we had a lot of work to do at this

new site. Last season the breeding success here reached 1.5 chicks per nest.

An average of one and a half chicks per nest were reared successfully during

the 2016/17 season. Considering that some eggs fail to hatch for a number of

reasons beyond human control, such a high breeding success is not easy to achieve.



If you look at the graph that I have attached for Argentina, you will see that

the graph drops from 100% to about 82% during the egg phase. Immediately after

being laid no eggs have been lost, so the breeding success begins at 100%. As

time goes by some eggs are lost and gradually the breeding success drops. The

graph shows that 82 out of every 100 eggs laid, or 82% of the eggs laid, hatched



After that the graph drops much less. It drops from 82% to 75% during the whole

chick rearing phase, which shows that chick losses were very low, which is a

very good indication that the colony is healthy and that food is in good supply.


It is impossible to control egg losses. They are caused by natural factors that

are beyond control. Most of the eggs that fail to hatch are caused by the egg

never being fertilised to begin with, or because the egg got cold at some point,

either because of bad weather, or because an inexperienced penguin left it uncovered

for too long. Some eggs are stolen by predators too, but that is not so common.

Eggs that are stolen are usually taken from nests already abandoned or left unattended.

The penguins have a viscous bite, and are more than capable of protecting their

eggs from foxes and other potential predators.


Virtually all the chicks that reached two or three weeks of age survived, which

shows that food is in good supply and that the colony is healthy. A breeding

success of one chick per nest is enough to maintain a healthy colony, so one

and a half chicks per nest is fantastic. Such a high breeding success is actually

quite unusual, and the population at Cabo Virgenes has increased by more than

11% since we began working here. It is certainly the most successful penguin

colony in Argentina, and I am not aware of any penguin colony anywhere that has

a higher breeding success.


Our colony in Chile has always been quite a healthy colony, averaging more than

one chick per nest since we began working here in 1998. However during 2009/10

the island suffered a very severe drought that killed off virtually all the vegetation.

With no vegetation to bind the soil, the wind blows the loose sandy soil all

across the island. The penguins here live in burrows, which usually offer good

protection, but the soil blowing along the ground falls into the burrows almost

24 hours a day, like a slow but continuos egg timer.


The penguins do their best to keep the soil out of their burrows, but it is difficult.

The soil falling into the burrow often builds up around the eggs, causing them

to get stuck in a small hollow. Eggs have to be rolled over regularly for the

embryo to develop, and when the egg gets surrounded by soil the penguins are

unable to rotate the egg properly, and it fails to hatch.


Ever since the drought, the penguins have suffered from lower breeding success,

well below one chick per nest. However, very slowly the vegetation has begun

to return, and each year the amount of soil being blown across the island has

reduced. Last year the breeding success finally exceeded the one chick per nest

that is required for a healthy colony.


If you look at the graph for Chile, you will see that the loose soil still takes

it toll on eggs and small chicks, but now much less than in the past. Last season

1.08 chicks per nest survived, which is very good progress, and more than enough

to keep the population stable and healthy.


One of our tasks when visiting our adopted penguins in Chile is to remove loose

soil if it is accumulating in the burrow. But there are more than 60,000 burrows

on the island, so we are only able to do it for our adopted penguins. The breeding

success statistics that I have given you are for the colony as a whole. Our adopted

penguins are visited regularly and receive special protection, so they have a

much higher breeding success. Our adopted penguins are so well protected that

most of them raise two chicks each year.


Finally the situation in the Falkland Islands has not changed much. The colonies

in Argentina and Chile have a good food supply because they are protected by

no-fishing zones imposed by the government to protect the penguins from commercial

fishing. The chicks are therefore well fed, and most chicks that hatch grow to

become fat and healthy. However in the Falklands the government provides no such

protection, and the commercial fishing industry removes most of the fish that

the penguins rely on to feed their chicks.


As a result only 0.19 chicks per nest survive, which is just one chick for every

five nests. The situation is not likely to change until the Falklands government

provides protection in the form of no fishing zones, like Argentina and Chile.

Whereas in Chile we remove loose soil from our adopted penguins, in the Falklands

we feed hungry chicks to ensure that they survive.


I would like to remind you that none of what we do would be possible without

your support, so thank you all for making it possible.


As soon as the penguins return home and lay eggs, I will send you a new photo

of Promises.


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Best wishes, Mike


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