Of what I speak is a seabird colony existing where the marine ecosystem has not been subject to wide-scale pollution from agricultural and civic runoff, fish depletion, introductions of alien species, harmful plankton blooms (“red tides”) and lots of other things that currently ravage most marine ecosystems of the “civilized” world. I speak of the Ross Sea, the last ocean on Earth where seabirds are capable of being too successful in their breeding. Hmmmm, yes, you heard me right. That is a statement that should give you pause for contemplation, and refers to a concept foreign to most marine ecologists. And what could I possibly mean by this? How can a colony of seabirds ever be too successful?

If you’ve been following my previous dispatches to Ice Stories for this recent Antarctic summer, one was called “Royds Tranquility” and another was “Beaufort Chaos”. In those I reported on the contrast between the Royds penguin colony (one “city” in this story, 2000 penguin pairs) and the more populous colony at Beaufort Island, the other city (60,000 pairs). The Royds colony was very quiet but at the time miserably failing owing to the 70 km walks that most parents were making to find the ocean and food…and 70 km back. The extent of fast ice was very unusual owing to very calm winds last winter and spring. Other than birds attempting to remain resolute on their nests, no others were present. Deserted eggs were everywhere, as more and more adult penguins giving up and going off to feed, their mates choosing not to return.

At Beaufort Island, where the ocean was at the penguins’ doorstep, just a short skip away, penguins were coming and going in multitudes, and because many nested in suboptimal habitat– being forced to do so because the good spaces had all been taken– some were losing their eggs too. But there were huge numbers of eggs still under other parents, being warmly incubated. In addition, due to a short journey from wintering areas just before nesting, all colonies, Royds included, began the season with their respective breeding populations at maximum, i.e. above normal. “Everybody”, it seems, attempted to nest! [If you’ve not read the earlier dispatches, perhaps do so before proceeding further in this one.]

About 40 km to the east of Beaufort, the colony at Cape Crozier was in a similar state to Beaufort: maximum proportion of a large colony, twice the size of even Beaufort (150,000 pairs), attempting to breed. Well, we could not follow up at Beaufort (couldn’t get there at the end of the season) but did have the opportunity in regard to Crozier. I think the stories for both Beaufort and Crozier were pretty much the same, although, being smaller, likely Beaufort didn’t have quite the problem experienced at Crozier.

At all our penguin colonies, there are the “super breeders” who almost always produce young– despite conditions– and then there are the “other” penguins. Mainly the super breeders have learned, through experience, about the vagaries of factors that penguins need to know about. This involves just 25% of the population, or thereabouts; the remainder of penguins almost always fail unless conditions are really easy. This season, the super breeders came front and center at Royds. Not only did they successfully hatch their eggs (unlike the klutzes) but also raised the maximum of two chicks. Therefore, even though 75% of nests failed, the total average chick production of the colony was 0.6 chicks per nest, which isn’t all that bad, given that in good years, an average 0.9 chicks are produced among all nests in which eggs are laid.

What these super breeders had figured out was that they could feed through narrow cracks in the ice and not walk all the way to the open ocean. Then, the ice opened into a polynya [patch of open water in the ice] off Royds, as I described in the “Minke Friends” dispatch. From then on, foraging was easy and the Royds chicks ballooned to become heavier than even last season, averaging around 3800 grams by the time they were 6-7 weeks old and within a week or so of fledging. That’s BIG for an Adélie penguin chick! As is the usual, the Royds chicks didn’t form crèches [groups of penguin chicks] because almost all the time, at least one parent was present to protect them.

Below are two images of Royds, taken on 17 January 2009, showing all the adults present. The reason that there are an equal number or more chicks than adults is because most chicks had a sibling…so two chicks for every successful nest.

Chicks and adults at Royds.

Penguin adults and chicks at Cape Royds, Antarctica.

So now, what about the other penguin city, the one at Crozier (standing in for Beaufort in this tale)? At Crozier, not only did a maximum number of birds attempt to breed, but almost all successfully hatched their eggs. This was because initially finding food was easy, as long as a parent only had its own mouth to feed. Not long after peak hatching, though, the parents began to make longer and longer foraging trips as they depleted food nearby. Of course these seabirds had help from whales and fish in this consumption, unlike the case for any other place in the World Ocean.

Chicks at first did ok, but once they reached the age of maximum growth rate, around 3 weeks of age, troubles began for Crozier. Eventually, parents’ trips reached three days long and less food was returned as some was digested on the trip back (these penguins hold the food in their stomachs, and then regurgitate it to their chicks — see previous dispatch — and once that cold wad begins to heat up in the parents’ stomach, it begins to digest, a common occurrence when the trip back to the colony is more than a day long). Well, basically the chicks at Crozier, though reaching appropriate size (height) for their age, became way under weight. At week 7 they were more than 1 kilogram (1000 g) lighter than Royds birds, and their feather development was halted. In fact, average weight was lower than we’d ever measured it at Crozier. Many chicks began to die of starvation. There were just way too many of them to be fed with the result that almost all were under-fed. In fact, breeding “success” at Crozier was 1.0 chicks crèched per original nest (it’s usually no better than 0.9). Wow! That’s a lot of chicks when you consider there were 150,000 nests to begin with.

Looking to the immediate future, it would seem that the chances for eventual survival of the Crozier chicks is close to zero, quite in contrast to the fat, vigorous but many fewer chicks at Royds. The Royds chicks should have a great chance for survival.

Below are images from Cape Crozier taken on 20 January. The contrast with Royds is dramatic, as almost no adults are present, even though the chicks are just a few days older than those shown in the images above from Royds. Sad.

Cape Crozier chicks with few adults in sight.

Cape Crozier chicks with few adults in sight.

Here you can see lots of chick carcasses. These chicks, unfortunately, have died of starvation. Also sad.

Crozier chicks and carcasses.

So, this is all pretty amazing, but we had to go through the entire season to see how things played out, and flip-flopped Royds vs Crozier. In the last several seasons (2001-2005), we witnessed somewhat similar events at Crozier, but chalked it up to effects of the big icebergs that were present then. The icebergs occupied a large portion of the Crozier colony’s foraging area.

Those icebergs have been gone now for two seasons. So, we have to consider other ideas to explain what is going on now. Perhaps, it seems, Cape Crozier has grown too large!! This rarely could happen to a seabird colony elsewhere in the world. Mostly this is so, because the population is kept low by pollution, toxic die-offs, invasions of feral animals or other type events; or breeding success is low owing to difficulty in finding food early in the season (over-fishing). In some warmer-water colonies of seabirds, where the environment allows the population to be present year round, a portion of large populations may just hang out in waters nearby and not participate in breeding. That doesn’t seem to be an option for migratory seabirds nor for seabirds that live in extreme environments, in both cases like is the case for Adélie penguins.

Well, ok, it was a very “educational” season for us, as are many. To complete our education, though, we have to be present in 4-5 seasons hence to tally the winners and losers among the penguin cities. That’s because young Adélie penguins spend their first years at sea and don’t visit the colonies.

For this season we are done, and here is what our camp at Cape Royds now will look like through the winter darkness. (See dispatch, “So, You Want to Be a Penguin Researcher?” for a view of the camp all set up.) In a couple of months you’ll need a flashlight to see this, our camp in a small box….well, a slightly large one.

Our camp.

Icebergs are broken off pieces of glaciers and contain snow that fell 10 000’s of years ago. When you move close to one, what you see is several 100 feet tall and yet only 10% of its actual size and you come to understand not only how much ice there is here, but also how long it has been here.

Sea ice to the horizon.

The end of a glacier as it comes off the land. Here you see frozen ocean holding the edge of the glacier ice in place. This wall of ice is 200 feet high with 9 times that much under water. That’s a lot of ice!

This is also part of a land glacier which has moved off the land over the ocean. It is called an ice shelf because although it is still attached to the land portion of the glacier it is floating on water. This shelf is the size of France and a couple thousand feet thick. That’s a lot of ice!!!

Icebergs off the coast of Beaufort Island. What you see is several 100 feet high, and only 10% of its size. These are enormous pieces of glacier that broke off from the ice shelf above, floated around for a while and are now grounded. Much of the year the frozen ocean holds them in place.

There is a lot of ice in Antarctica.

A tranquil scene at Cape Royds: penguins quietly sitting on eggs, dreaming of food, 65 km away. But, tranquility sometimes can be deceptive. Kind of like the Western Movie where one guy says, “Its quiet out there, isn’t it?” And Tex says, “Yes, too quiet!” Then a big shooting battle starts.

The colony has certainly been quiet, with very few birds coming in or going out to sea. In my first dispatch of the season (“The Early Returns”) I detailed the fast ice situation: a continual sheet of ice out to beyond the horizon. Its edge at the open water is about 60 km away now; at the beginning of the season it was at 75 km. Walking about 2-3 km/hour that distance adds 30 hours to a trip, not counting times for resting or checking that there are no leopard seals at any wide cracks along the way. I can recall seeing 3 cracks on trips that we’ve flown out to Beaufort. Penguins can wait at these for hours to make sure nothing nasty lurks in those black waters in the channel between the white ice.

The penguin pairs are well coordinated in their schedules but there is very little cushion for major delays. Adding a day or two to a trip can spell disaster to the bird on the nest who is dreaming of a fish or krill dinner. Well, it’s a disaster for both members of the pair! In fact, this season has been a disaster so far for many. I’ve been keeping track of 38 nests of banded, known-age birds since early Nov. As of today (12 Dec), 55% of nests in which eggs were laid have failed. Each nest started with one or two eggs, plus of course the incubating bird. Such a loss rate means that lots of birds incubating the eggs waited way past comfort…stomach growling…and finally had to leave. Males are prepared to sit for two weeks or a bit more while taking the first turn at incubation. They can lose 30% of their body weight or more awaiting their mate to return.

Here is a penguin that can not wait a minute longer. He has been staunchly taking care of these eggs for 3 weeks, and now it is time to eat. His mate is no where to be seen, but he’s got to go. That’s the way it’s been so far this season, males taking very long first responsibility on the nest while the females search for food in order to be able to sit for weeks when she arrives back.

Sometimes skuas can intimidate penguins to leave. The skuas just sit there staring at the penguin for hours, just out of pecking range. The penguin can’t take it any more. Or, sometimes one skua pesters the penguin by pulling its tail, and then the other grabs the egg when the penguin reaches back to peck the tail-pulling skua.

A few weeks ago there would have been 25 nests in the foreground of this view. Now there are 13 and all are vulnerable to skua staring as there is space free of penguins around every nest. Neighbors are needed to guard one another’s flanks.

A fine meal for a skua, offered by a penguin who had to go in search for its own food.

You can see the result of many birds having given up: broken eggs everywhere. This is quite different from Beaufort (see last dispatch). These nests didn’t roll out of poorly built nests…just look at all the rocks in these nests. These eggs were left by the penguins, and the skuas then arrived to eat them.

Well, so, things are looking kind of bleak at Royds this season, certainly a stark contrast to the ‘happy’ chaos of the Beaufort Island colony and a stark contrast to last season at Royds!!! Many, many 10’s of thousands of chicks will be produced there at Beaufort, in spite of the seeming chaos. What’s with this global climate change? They said it should be getting windier in these parts, and the wind would blow the ice away. I think they also said the weather would be getting more unpredictable and more wildly varying. I guess they got that part right! Kind of sad, though. Gotten rid of your gas guzzler yet?