Antarctic birds: Giant Petrels

With the penguins and the ‘gull-like’ birds out of the way, it’s time for my favourite group of birds (not only on Antarctica but overall, I would say): the Tubenoses. A large, diverse group of birds that are highly adapted to life at sea, which is also the place where they are most at home. They only come to land to breed and will probably give up doing so as soon as they figure out a way to incubate and raise their young on the wings as they look very clumsy and vulnerable on land. It’s also a group where many species are threatened, some even close to extinction. As many of these birds call the Southern Ocean their home for at least part of the year, there is a big range of species we can see on a trip to Antarctica, either in the crossing of the Drake Passage or other sea passage in the Southern Ocean, or breeding either on Antarctica or on any of the subantarctic islands. So, without further ado, let’s start with the first two species, both Giant Petrels.

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Southern Giant Petrel – not the big ‘tube’ on the bill, the end of their salt gland.

The bill of the Giant Petrels is interesting for two reasons. First of all, it clearly shows the tube that gives the family its name. This is the end of the salt gland, which the use to excrete the excess salt they get from their marine lifestyle. Secondly, it shows the best characteristic to separate the Northern from the Southern Giant Petrel. The main difference between the two is the tip of the bill. It’s pale green in Southern Giant Petrels and dark red in Northern Giant Petrels. Their plumage is highly variable, ranging from dark brown to almost entirely white, but this goes for both species. Only the nearly complete white morph (with only a few dark feathers) is exclusive for the Southern Giant Petrel.

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Southern (top) and Northern Giant Petrel in flight. The difference in plumage colour is not distinctive (could easily have been reversed), note the different bill tips.
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A white morph like this is exclusive to Southern Giant Petrels (also note the bill tip again)

Both Giant Petrels are very opportunistic feeders, in summer they are often seen near penguin colonies trying to steal an egg or chick or scavenge on carcasses of penguins and seals. At sea, they are often seen behind fishing ships, feeding on discards or on other things that float on the surface.

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A Southern Giant Petrel trying to catch a Gentoo Penguin chick
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A Northern Giant Petrel scavenging on an Antarctic Fur Seal pup

They usually breed in very loose colonies and make a nest on the ground. Where they are generally not shy at all, during the breeding season this changes. They suddenly become shy and vulnerable on the ground, and it’s advisable to stay at a reasonable distance from their nest. They lay one egg, like all tubenoses, which is incubated for nearly two months by both parents. Both parents take care of the chick for another three to four months before it fledges.

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A Northern Giant Petrel with chick near a King Penguin colony

When given a good look, both species are easily identifiable, even at sea. They are impressive birds with a wingspan of up to 2 meters that seem to fly effortlessly through the sky.

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Somehow they have a bit a prehistoric look over them – Northern Giant Petrel

 

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