> Dear PenguinPromises
>
> The penguins have been doing really well since I wrote to you last. The weather
> has been very mixed, with some really hot days, and some cold windy days. The
> temperature reached 26°C (79°F) just a few days ago, which is very hot for southern
> Patagonia.
>
> Thankfully we have not had much rain in the colony, so that has been good news
> for the chicks. Despite being penguins, the chicks do not like getting wet. They
> do not have the waterproof feathers of Promises when they are small. The fluffy
> feathers keep the chicks warm when they are dry, but are like a woolly sweater,
> and do not help in the rain at all.
>
> It is up to Promises to keep the chicks safe and dry during rain when they are
> little, but the chicks are now big enough that rain no longer bothers them. They
> are now big enough to leave the nest and explore their surroundings. I attach
> a photo of your chicks doing just that.
>
> When the chicks are newly hatched, they do not have the ability to create enough
> internal warmth. Just like human babies, they rely on the parents to keep them
> warm.
>
> As the chicks grow, in addition to increasing in size, they also go through a
> number of internal changes, one of which is the growth of special cells that
> convert food into heat. Those special cells are like microscopic heaters distributed
> throughout the body.
>
> All warm-blooded animals develop these cells in order to generate their own body
> heat, which is the definition of being warm-blooded. By comparison, cold-blooded
> animals such as snakes and insects have no internal heating, and rely on the
> surrounding temperature.
>
> The ability to produce their own body heat allows the chicks to now shed their
> fluffy chick feathers and replace them with waterproof feathers. They cannot
> go out to sea until that process is complete. That process has already begun
> and will take at least another month to complete.
>
> Since they hatched, the chicks have been healthy and are growing very quickly.
>
> This year has been an excellent year for the penguins. I attach a photo of the
> colony and you can see that there are large healthy chicks everywhere. Most of
> the penguins you can see are chicks. There are only a few adults around during
> the day.
>
> Up until recently each penguin couple has been taking turns at going to sea to
> catch food for the chicks. One of the couple stays at home in the nest with the
> chicks, to keep them safe, and the other goes to sea to catch fish. Then the
> next day they swap over.
>
> By taking turns, both penguins get one day out at sea to catch food, and one
> day back home in the nest with the chicks. Up until recently that strategy worked
> very well, but now it has changed. The chicks are eating too much, and the parents
> cannot catch enough fish to keep them fed working alternate days.
>
> It has reached the point where one penguin cannot catch enough food to keep the
> chicks fed. So the penguins have been forced to give up working in shifts. Both
> parents are now leaving the colony to catch food each day. With both parents
> now going fishing, they can catch twice as much fish for the chicks.
>
> Of course, leaving the chicks on their own during the day is risky, and is not
> something that Promises would do by choice. However the chicks must get more
> food in order to survive, and there is no other way of getting more food for
> them. Every penguin in the colony has made this change in order to keep their
> growing chicks fed.
>
> The chicks don't like being left on their own either. The parents have always
> been by their side since they hatched. The chicks have never been left alone
> for a single minute up to now, so this is a scary time for them.
>
> Now when the chicks are left alone during the day they mix with other chicks
> in small groups, to play together, and for safety. The chicks feel safer when
> they are together in a group with other chicks. As you can see in the photo,
> there are small groups of chicks throughout the colony.
>
> During the day there are now just a few adult penguins in the colony. At this
> time of year dawn comes early in the morning, at 05.00 hrs, so that is when the
> day starts for Promises. The penguins' food is all out at sea, so there is no
> point wasting time on breakfast when there isn't any.
>
> The penguins just wake up and head straight off to work. They don't need to get
> dressed, or brush their teeth. They are already fully dressed, and birds do not
> have teeth.
>
> It takes about 20 minutes for Promises to walk down to the beach, and then another
> 2 hours to swim out to where the fish live. Some days the penguins find the fish
> quite quickly, and some days it takes a long time to find them.
>
> The problem is that the fish do not stay in the same place. It would be a lot
> easier for Promises if they did. The fish move around to different places each
> day, following blooms of plankton and invertebrates which are what the fish feed
> on.
>
> So every day the penguins have to look for the fish shoals again. Once they find
> the fish, then they have to start catching them.
>
> The penguins begin by taking a deep gulp of air before diving under the water.
> Penguins are birds, so Promises must breathe air like all birds do. The fish
> can stay under the water all the time, but penguins have to come back up to the
> surface every few minutes to take a breath of air.
>
> As a general rule amongst aquatic birds and mammals, the larger an animal is
> the longer it can remain underwater without air. Whales can remain underwater
> for an hour or two, but Magellanic penguins can only last about 3 minutes when
> hunting and burning up energy. So their hunting dives have to be short and precise.
>
> The penguins dive straight down to about 30 or 40 meters (100 to 130 ft) below
> the surface, which is a long way underwater considering that they only have 3
> minutes. That is approximately a ten storey building downwards below the water.
> The penguins then stop for a few seconds to look upwards at the fish above, and
> decide which fish they should try to catch. They only have time for one attempt.
>
> Looking upwards from that depth, Promises can see the fish easily, but the fish
> can't see Promises. The fish are highlighted against the bright sky above, making
> them easy to see, whilst the penguin's black feathers are difficult to see against
> the gloomy depths below. The penguin chooses a fish to catch, and then starts
> swimming upwards as fast as possible to catch it.
>
> Most of the time the fish do not see the penguin coming at all. The penguins
> take them by surprise coming up from below out of the gloom at high speed. The
> head, back, and all of the penguin's upper parts are all black, so the penguins
> cannot be easily seen coming up out of the gloomy ocean depths.
>
> That is why most seabirds are black above and white below when they have their
> wings or flippers outstretched. That combination makes them hard to see from
> above against the dark ocean below, and also hard to see from underneath against
> the light coming from above.
>
> Birds on land have so many different colours/colors, but seabirds are usually
> variations of black and white, and that is why. A universal colour-scheme for
> land birds would not work, because the land can be so many different colours,
> but the deep ocean is always dark.
>
> The penguins come up fast and bite the fish to catch it. The hook on the upper
> tip of the beak pierces the fish and stops the fish from slipping out of the
> beak during the impact. Compared to other penguins, Magellanic penguins go for
> larger fish and attack quickly by surprise. That hook is vital to their success.
>
> If that hook did not pierce the fish, the high-speed attack of the Magellanic
> penguin would likely cause the slippery fish to slip out of the beak during the
> impact. Even a dead fish is difficult to grab with chopsticks underwater at high-speed.
> If the fish did slip out of the beak, the penguin would not have time to turn
> around and dive back down to retrieve it. By now the 3 minutes are up so there
> is only time for one attempt.
>
> I attach a close-up photo of the beak so that you can see the downward pointing
> hook more clearly. The lower bill is slightly shorter to accommodate the hook,
> which is almost invisible with the beak closed. As I mentioned last month, that
> beak also keeps Magellanic penguins safe from predators on land.
>
> Many species of penguin lack this hook, and those species generally catch smaller
> fish and invertebrates, or catch their fish in a different manner.
>
> Having caught the fish securely, the penguin continues up to the surface where
> it then swallows the fish whole, head first. Penguins do not chew their food.
> Penguins are birds, and birds do not have teeth, so they swallow their food whole.
> Playing with their food would also invite the ever present seagulls to steal
> their meal, so the quicker their prize is safely swallowed the better.
>
> Each penguin begins by eating enough fish for itself. That food is quickly digested.
> Once they have eaten enough food for their own needs, the penguins then start
> catching fish to take back home to the chicks.
>
> The fish for the chicks is taken back home to the nest in their stomach too.
> Many birds have what is called a crop, which is a special pouch in the throat
> that birds use for storing food for their chicks. Penguins do not have a crop.
>
> Instead the fish for the chicks is swallowed and passes directly into the stomach,
> but the penguins turn off their digestion so that the fish for the chicks is
> kept in their stomach without being digested. The seawater that is swallowed
> with each fish dilutes any remaining stomach acid and stops digestion until new
> acid is produced after the chicks have been fed.
>
> The penguins can even prepare different recipes for the chicks. When the chicks
> are very small, the adults mash the food up in their stomach prior to feeding
> it to the chicks, so that it is mushy and easy to swallow. Tiny chicks would
> choke on large pieces of fish.
>
> Then as the chicks get bigger Promises can change the recipe, so that the fish
> is not mashed up so much. The chicks slowly learn to eat larger pieces of fish,
> instead of mushy fish.
>
> When the penguins have caught so much fish that their stomachs will not hold
> any more, they head back home to the nest. It takes another two hours to reach
> the colony, and then another 20 minutes walking back to the nest. By now the
> chicks are waiting for Promises with rumbling tummies. They are very hungry because
> they have not had any food since the day before.
>
> After the chicks have eaten all the food they can manage, they usually fall asleep.
> The parents then spend time preening the chicks. If the chicks have not already
> fallen asleep, then having their feathers preened by Promises is sure to send
> them to sleep.
>
> Preening the chicks' plumage is very important. Here in the penguin colony there
> are lots of parasites, such as fleas and ticks. Those parasites suck the chicks'
> blood, and often carry diseases.
>
> In order to keep the chicks healthy, it is important for Promises to spend family
> time with the chicks at the end of each day. The parents run their beaks through
> the chicks' feathers, removing all the fleas and ticks that they can find. If
> the chicks were not preened daily they could become sick from the parasites which
> the chicks can't remove by themselves.
>
> Penguins do not have any hands, so there are areas that penguins cannot reach
> by themselves. They cannot reach their head and neck for example, and that is
> where the parasites collect in large numbers if they are not removed by another
> penguin.
>
> As well as preening the chicks, the couples also preen each other to remove the
> parasites from those areas that they cannot reach themselves. In addition to
> being an important part of keeping clean and healthy, this time together also
> helps the penguins to strengthen their relationship as a couple.
>
> For the next few weeks, the daily routine for Promises will be getting up at
> 5 o'clock in the morning, spending the whole day fishing, coming back home to
> feed the chicks, and finally spending family time with the chicks before bed.
>
> During that time the chicks will shed their fluffy chick feathers, and grow waterproof
> feathers, ready to leave the colony and set off on their own as juveniles. I
> will write to you again in another 5 or 6 weeks with all the details of that.
>
> Kind regards, Mike
>
>
>
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