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.

We heard that sound again two days ago at Cape Royds, having heard it before in January 2005, when a several square kilometer opening appeared in the fast ice just offshore in a matter of hours. The ice was dissolving, or would we call it melting?, and it was happening so fast that you could see it disappearing without even needing your imagination to be going overtime. It’s kind of like putting an ice cube in a cup of boiling tea water to watch it disappear; only here the water is just a degree above freezing. That’s plenty warm as ice goes. In 2005 the fast ice was thinner, so it went from white ice to blue water; this year it was much thicker, so for a couple of weeks it slowly turned darker shades of gray, as it took on more water. Then, fzzzzzzz.

Otherwise, except for this new patch of open water within the ice, called a polynya (a Russian word; without a doubt the Inuits have a name for this, too), there is still fast ice to the horizon as I have described in various of my previous dispatches.

The Swedish icebreaker Oden going south, very slowly, through the ice a few kilometers out in McMurdo Sound, while a polynya begins to form next to Cape Royds.

The south ‘shore’ of the polynya, the day after it initially formed, showing proximity to the Cape Royds penguin colony (tan area on left side of image). The polynya is to the right, beginning to dissolve the gray ice in the center of the image.

In fact, in the Arctic, Inuit villages — and, for that matter, seabird colonies — are located near to polynyas. And, wouldn’t you know, so are penguin colonies, although at the opposite end of the Earth. This is because polynyas allow these predators much easier access to their food. Normally, McMurdo Sound is one big polynya, and the penguins are here at Royds because of it. As I’ve been making the point in previous dispatches, the Royds penguins have been having a hard time of it this season, because their polynya didn’t form, owing to calm winds which allowed the ice to thicken until not even the strongest winds could blow it away. So, they’ve had a very long walk to get food. That is, up until a few weeks ago, when the few remaining penguins still having chicks were provided a large crack to feed in, just 4-5 km north of the colony. Now they’ve got a full-fledged, mini-polynya and all is right in the World!

Well, just like in 2005, within a day of the polynya forming, a couple of minke whales showed up in it! Where they came from, I’m not sure, but they may have followed the Oden into the ice (35 km from the fast ice edge), and then pealed off when a crack that intersected the icebreaker channel allowed them to get to the Cape Royds polynya. Maybe they heard it fizzing! Or the sounds of joyful penguins!

The minke whales, for several hours, cruised around the polynya feeding all the time. They’d submerge for 6-8 min at a time and likely were like big “Hoovers”, i.e. vacuum cleaners. Between dives, they exhaled (i.e. whale “blows”) 4-5 times, clearly audible in the still air from a kilometer away. Within a couple of hours after the whales’ arrival, the penguins’ diet switched from krill to fish. I’d been monitoring it by watching what passes between adult and chick everyday for the past few weeks. Wow! I knew that the whales could do this to the penguins, but I didn’t realize that the whales were so efficient! Not long after the whales left (they’ve not been seen for about 24 hours now) the penguins’ diet switched back to krill. Therefore, this is pretty good evidence for what we call “interference competition”. The whales certainly eat a lot but also their vacuuming causes the krill to try to escape, of course. And what krill do when being pursued, if they can, is to dive deeper and, it seems, deeper than penguins want to go, especially when there are enough fish to be had at shallower depths, though apparently not in a density that in this case would interest a minke looking for easy pickings. If the whales had vacuumed all the krill, when they left, there would be no food for the penguins. As it was, the krill ventured back up into the light (where the phytoplankton occurs that the krill eat), to then be caught by the penguins again. Both whales and penguins go for the easy meal, i.e. that nearest the surface.

Parent feeding its chick. With binoculars, if you get the right angle, usually it is possible to determine whether krill (pink) or fish (gray) is being fed to the chick.

Well, so, you’d think that maybe whales are an annoyance to Adélie penguins. As it turns out, though, minke whales are life savers! Adélie penguins, if given a choice, would always want to have minke whales around, despite the whales’ appetite and despite the best (?) efforts of the Japanese whalers. You see, minke whales — because, like Adélie penguins, they are pack ice denizens — have evolved a very long and sharp “beak”. When you see the whales in areas were the sea is freezing, it becomes quickly obvious why this is a good thing. The whales use their rostrum to break breathing holes in the new ice.

This ice is thick enough that penguins walk over it. With the whales around, though, the penguins can swim between whale breathing holes much faster than walking. In fact, several years ago, when on an icebreaker at the time of ice freeze-up in the Amundsen Sea, one day there were whales and penguins swimming around, and then the next day, with a dramatic drop in temperature and a freeze, there were whale holes but no whales or penguins. Together, they had escaped north far enough to move away from the area of freezing.

A minke whale pushing up through recently frozen sea ice, the ice around it being 4-5 cm thick.

All but one of these penguins found a hole left by a minke whale; the next whale breathing hole is just behind the lone penguin and this flock of penguins is next going to appear in that hole.

These penguins are not walking on frosted glass. They are walking on ice thick enough to support their weight, but not thick enough that a minke whale could not break a hole.

It is good for Adélie penguins to have as many minke whales around as possible. This one, like the pied piper, is making a “channel” through new ice, soon to be followed by a flock (school?) of penguins, who would much rather swim than walk.

Penguins need whales, especially minke whales, as friends.

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?

MCMURDO STATION, ANTARCTICA– The Hagglund awaited us as we prepared to depart for sea ice training. This was a requirement since our expedition is to be based on the ice that forms over the ocean of McMurdo Sound every austral winter. We had to learn how to identify cracks and do thickness profiles of the ice across them, how to determine if a crack was safe to cross depending on what type of vehicle we were traveling in, and how to make ice anchors to secure things like our tents or equipment to the ice.

The Hagglund that brought us out to the sea ice.

The first introduction was looking at the tide crack just off from McMurdo Station. This forms between the fast ice which is attached to land and doesn’t move and the sea ice which succumbs to the rising and falling of the tides. A tide crack forms everywhere where there is sea ice meeting land. We poked at it with bamboo poles to check for snow thickness and competency to make sure where we were walking was secure.

The tide crack at the transition between the fast ice near McMurdo Station and the sea ice.

We hopped back into the Hagglund and drove north along the flagged Cape Evans Road in search of cracks between plates of sea ice. We drove past the Erebus Glacial Tongue, through the Dellbridge Islands which are actually the high points of a former volcanic mountain that is buried beneath the ice. Soon we came up on the crack we were looking for.

Driving along Cape Evans Road.

We pulled up to some flags marking a crack that crossed the roadway. Now we would learn how to travel safely across the sea ice. Most first-year sea ice is about 2-meters thick (or about 6.5 feet), but the minimum thickness of ice to travel on is 30 inches, so in most cases we would be okay. The gap that forms in a crack is of critical importance to determine whether or not you can ride across it, and the minimum width is dependent on the length of how much of the vehicle is in contact with the surface. A crack is considered safe to cross if it is 1/3 or less of the length of the vehicle treads.

Flags marking a crack crossing the Cape Evans Road.

First thing when approaching a crack is to identify the edges of it by poking a bamboo pole into the snow. The snow should be excavated across the crack down to the ice surface. Then you drill to penetrate through the ice into the underlying water. This is done on either edge of the crack and in the gap. The thickness of the ice is measured through the drilled hole and recorded. The profile of the crack is then complete. The ice around the crack we analyzed was more than 30 inches and the width of the crack was less than 1/3 of the length of the vehicle, so it was determined that it was safe to cross and we carried on.

Profiling a crack in the sea ice – drilling to determine ice thickness.

One of the more important things we learned was how to make a V-thread ice anchor. Being out on the sea ice there is very little snow cover. V-threads are used to secure things to the ice. The wind can be very strong in Antarctica, and anything not secured will surely blow away. V-thread ice anchors are constructed by drilling into the ice either with ice screws, as pictured below, or by using a drill.

Making a V-thread ice anchor.

Two holes are drilled at about 45-degree angles that intersect each other. A piece of strong rope is passed through these, knotted together, and anything that needs to be secured is lashed to the anchor line. The ice is quite strong, and when the wind blows powerfully, the ice anchors will make sure nothing blows away.

Once we were finished with our training we turned and headed back toward McMurdo Station with a steaming Mt. Erebus looming above us amid a picturesque swirling wispy sky.

Mt. Erebus steaming in the distance.

We could see the remains of an iceberg nearby that became locked within the sea ice when it froze during the earlier winter.

Remains of an iceberg frozen in the sea ice.

We passed through the Dellbridge Islands that we came through on our outbound journey.

Tent Island (left) and Inaccessible Island (right) of the Dellbridge Islands.

Yet what was in store was the highlight of the day. We found out that our next destination was an ice cave…

Canada glacier, Antarctica. Glaciers are slow-moving rivers of ice, fed by compacted snow.

Fast ice is a type of sea ice that isn’t really speedy—it’s “stuck fast” to land.

Pancake ice forms when flat chunks of ice are battered into rounds by wave action.

Sea ice breaks up into brash ice, ice chunks less than 6.5 feet (2 m) across.

For those who think ice is all the same: think again. At the poles, ice takes many forms—from shiny “grease ice” on the sea surface to mile-thick ice sheets that cover entire continents.

The many varieties of ice found at the poles arise from the various environments in which they form: on land, at sea, and at the boundary between the two.

On land, snow falls and hardly ever melts. Year after year, snowfall piles up and compacts into ice that flows like a slow-motion river—a glacier. When glaciers are bounded by mountains, they carve deep U-shaped valleys on their way to the sea, valleys that remain long after the glacier has melted away; Yosemite Valley in California is an example.

When glaciers stretch out across flat land or over an entire continent, they’re called ice sheets; both Greenland and Antarctica are almost entirely covered by ice sheets that are miles thick. Within ice sheets, faster-moving zones called ice streams occur over water or smooth ground. Smaller ice sheets that sit on mountaintops are called ice caps.

When ice from glaciers and ice sheets reaches the sea, it can spread across the water as a slab called an ice shelf. Ice shelves can extend for miles—even hundreds of miles—over the ocean. Chunks of ice can break off from an ice shelf, forming floating icebergs.

In Arctic climates, even land that seems ice-free may hide a layer of ice beneath its surface. Permafrost is a layer of soil that remains frozen year round.

Sea ice forms when temperatures dip so low that the ocean itself begins to freeze. Sea ice can be free-floating drift ice, or fast ice that is “stuck fast” to land. When sea ice first begins to form, it appears as fine bits of frazil ice, then thickens into soupy grease ice, and then sometimes forms pancake ice, pieces of drift ice that have been battered into rounds by waves and collisions. When pieces of drift ice get packed together, they become pack ice. An ice floe is a solid chunk of drift ice up to 6 miles (9.7 km) across; if it grows larger than this, it’s called an ice field.