When the chicks were small, it was important for one of the adults to always be around to protect them from predators. Now as they get bigger, the chicks need increasingly large amounts of fish to maintain their growth, and both parents must now go to sea to catch enough fish to satisfy the chicks' increasing appetite.
Despite being only a few weeks old, the chicks are now nearly as big as Ice Ice Baby, and need a lot of food.
With both parents away from the nest for much of the time, the chicks get more adventurous, and begin leaving the nest on their own. This makes it easier for us to take photos, and I now attach a photo of the chicks.
Although the chicks are now nearly as big as Ice Ice Baby, they still have a lot of growing to do. It will be about 4 to 6 weeks before they are ready to go to sea on their own.
First they need to shed out the soft fluffy feathers which you can see in the photo. These fluffy feathers are excellent at keeping the chicks warm when they are dry, but they are useless in the water. These feathers are not waterproof, and would soak up water like a sponge if the chicks went into the water, making it impossible for the chicks to swim.
So over a period of about three weeks the fluffy feathers fall out and are replaced by sleek waterproof feathers. These new feathers are just like those of Ice Ice Baby, except that the markings are different. The chicks will not develop the markings of the adults until they are 5 years old, and this change in markings indicates to other penguins that they are mature enough to take a partner and begin rearing chicks of their own.
The five years it takes to reach maturity are necessary for the chick's body to develop full muscle strength and stamina, and for the chick to become a master at catching fish. Without years of practice to become an expertise fish-catcher, the young penguin would not be able to catch enough fish for its chicks, and any other penguin pairing up with such a young penguin would be unlikely to be successful at raising chicks either. It is for this reason that the juveniles only develop adult plumage when they reach 5 years of age, to prevent other penguins from pairing up with inexperienced penguins.
The other change that the chicks need to undergo before going to sea, is the strengthening of their flipper muscles. The chicks have put down large deposits of fat over the last few weeks, which will be very important in providing the energy reserves they need to stay alive whilst learning to catch their own food.
But up until now the chicks have been confined to their nest with virtually no exercise, and their flippers have never been used, so the flipper muscles are small and weak.
Now that the chicks can wander out of the nest, they begin exercising their flippers, in order to strengthen their muscles. They can often be seen flapping their flippers up and down vigorously, as though they are excited at the prospect of getting into the ocean. The strength and stamina of their flipper muscles will be very important for the speed they will need to catch food when they begin life on their own in a few short weeks.
The chicks are very sociable, and mix with chicks from adjacent nests. Just as children go out to play with their friends, so too penguin chicks seek out other chicks for company, and it is common to find four or six chicks all in the same burrow. The adults do not mind other chicks visiting their burrow (it provides extra protection for their chicks against predators), but they never let other adults enter their burrow.
This season has been very dry, with very little rain, and this has led to differing fortunes for our colonies. Our penguins in Argentina have benefited from the reduction in rain, and chick survival rates have been high there this season.
The low rain fall has not really affected the vegetation there, which comprises mostly of drought-resistant thorn bushes, with deep root systems that seek out moisture during drought. The penguins use these bushes as cover for their nests, since the soil is too sandy to support burrows..
However here on Magdalena Island in Chile there are no bushes. The vegetation is short grass and small flowering plants, with relatively shallow roots, growing over a sandy soil. These have suffered badly from the drought, and most of the vegetation has died off leaving bare soil. The wind turns this loose sandy soil into dust storms, which in some areas are so severe that they bury the entrance of the burrows, with the penguins still inside.
Ice Ice Baby and the other adults are wise enough and strong enough to dig out the soil that comes into the burrow, but the chicks are not. They very often retreat to the back of the burrow, unaware that they are being sealed into their own tomb by the storm. Recently we have had to dig out several burrows to rescue the chicks trapped inside. If it were not for the burrow markers we use to name the penguins, many of the burrows would have completely vanished from sight.
Rain is desperately needed to restore the short grass cover, which in turn is needed to stabilise the soil in order to secure the long-term future of these penguins.
The chicks will begin leaving the colony in a few weeks, and I will write to you again when that exodus begins.