Penguins South America update


>

> Dear PenguinPromises

>

> The chicks have now left the colony and have gone to sea to begin life on their

> own. They are now swimming up the coast of Patagonia towards Brazil. In a few

> weeks time Promises will follow them to Brazil, but first there are things that

> all the adult penguins must do before they can leave.

>

> When young birds leave the nest they are said to have fledged. In reality the

> word refers to birds that can fly, but even though penguins cannot fly, the word

> fledged is still correctly applied to penguins in both common language and scientific

> reports.

>

> Once the chicks have fledged they are then called juveniles. The term juvenile

> refers to what might be considered a penguin version of a human teenager. They

> are now able to live independently from their parents and make their own way

> in the world, but they have still not finished developing to attain their full

> weight and strength.

>

> These juvenile penguins weigh just over 3 kg, which is almost half the weight

> of Promises. The difference in weight is due to the difference in muscle mass

> and bone density which develops over time. Summers are short this far south,

> so to avoid feeding chicks in winter, the chicks are ‘fast tracked’ to reach

> independence, and then they finish their physical development after leaving the

> colony.

>

> Although juveniles are almost the same height as Promises, their body is very

> different. When holding a juvenile penguin it has the feel of a soft toy. Its

> body is mostly fat reserves which are soft and squidgy. These body fat reserves

> are important to provide energy reserves that will keep the juvenile alive during

> the first few weeks as it learns to catch its own food.

>

> By comparison holding an adult penguin, like Promises, it is as firm to the touch

> as a car tyre, due to the strong bones and powerful muscles beneath the feathers.

> It is for this reason that juveniles take 5 years to reach breeding age.

>

> The juveniles have never been swimming before, so for the first few weeks their

> flippers get tired very quickly, and they need to take lots of short breaks when

> swimming. They swim for a few minutes at a time, and then float on the surface

> resting for a while, like the juvenile in the photo. Over the coming weeks and

> months their muscles will get stronger and they will spend less time resting

> and more time swimming.

>

> The juveniles’ weak flipper muscles also affect their speed. The juveniles are

> not yet fast enough to catch fish, so for now they will have to eat slower moving

> creatures like shrimps and krill, which they catch amongst the beds of seaweed.

> That is the same brown seaweed that you see floating near to the coast all over

> the world. It is called kelp. Kelp beds are like underwater forests, full of

> delicious food if you are a juvenile penguin.

>

> The adult penguins eat almost 100% fish, but the juveniles have to be more flexible

> in their diet for the time being. For the next few weeks they will be grateful

> for anything that is slow enough to catch.

>

> Summer is now coming to an end, and it will start getting colder here on land

> before long. However the open ocean is so large that away from the shallows near

> to the beach the seawater does not get much colder in winter. The reason is because

> it is so vast and contains so much water.

>

> If you boil a kettle, after you turn it off the water inside stays warm for some

> time afterwards. That is because the heat has to escape for the water to cool

> down. The larger something is, the longer it takes for that heat to escape. A

> cup of hot water cools down quickly, but a large pot of water takes much longer.

>

> The South Atlantic Ocean stretches from South America to South Africa. It contains

> so much water that it would take years to cool down, and the winter isn’t long

> enough for that. So for animals living in the ocean here, there is not much difference

> in temperature between winter and summer.

>

> The juveniles will not be getting cold in any case, because they are swimming

> towards Brazil, where it is nice and warm all year round, even on land. The juveniles

> will not begin laying eggs themselves until they are 5 years old, so they have

> no need to come ashore to make a nest until then. Penguins love living in the

> ocean, and they only live on land when they must. Penguins only come ashore to

> raise chicks and to moult their feathers.

>

> The juveniles will spend the next 5 years just eating and sleeping out at sea.

> During those 5 years they will build up their muscles and bones for the day when

> they will need to be fast enough to catch lots of fish to feed chicks of their

> own, just like Promises.

>

> So whilst the juveniles are away enjoying themselves, Promises and the other

> adults have some rest and relaxation of their own to take car of. The parents

> have been working from 5 o’clock in the morning until late in the evening to

> keep their chicks fed and healthy. That was such a sacrifice that the parents

> are now exhausted and have lost 20% to 25% of their body weight. It is important

> for Promises to now recover the weight lost during chick-rearing.

>

> So for the next few weeks Promises will go out to sea and remain there just eating

> and resting. Now that the chicks have left the nest there is no need for Promises

> to go back to the nest at night. To make a five to six hour round trip each day

> between the fish and the nest makes no sense now that there are no chicks to

> feed. So the penguins remain where the fish are, and sleep bobbing up and down

> on the waves out at sea.

>

> Building the weight back up is very important for Promises, because in a few

> weeks time the penguins have to change all their feathers, which is called moulting

> or molting, depending on where you live. For penguins, moulting is a big deal

> because they cannot go swimming during the moult. Since the fish live out at

> sea, that means that Promises must go for almost a month without being able to

> eat anything. So you can see why eating plenty of food now is important.

>

> I will write to you again in a few weeks time when Promises has finished the

> mini-vacation out at sea, and is back in the nest again ready to begin the moult.

>

> Kind regards, Mike

>

>

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