All posts by George Divoky

It Takes a Colony to Raise one Young

Cooper Island, Alaska, Aug. 27, 2009 — What seems like a long,long time ago,black guillemots on Cooper Island had the best of all possible worlds. The summer snow-free period was increasing annually, providing breeding birds with more time to raise their young, and the Arctic pack ice was close enough offshore that there was a readily accessible supply of Arctic cod to feed the nestlings. The only real dark cloud on the horizon was the realization, slow in coming over the past three decades, that the warming planet that had given the guillemots their “salad days” in the 1970s and 1980s could cause increasing melt of the pack ice, making Arctic cod less accessible and causing problems for parent guillemots provisioning their young in August and early September.

Even as the ice kept retreating during the 1990s there were reasons to think the guillemots could cope with the change in prey type and availability since even though this subspecies has specialized on prey associated with Arctic pack ice, the genus to which it belongs, Cepphus, is highly adaptable and lives on a wide variety of near shore prey in temperate and subarctic waters. It appeared that documenting how the Cooper Island guillemot population, with its many color-banded individuals, responded to an ice-free nestling period was going to be a rare chance to watch adaptation and selection in a wild population.

But this past summer suggests that the geographic shift in the guillemots’ prey may not be the deciding factor in the future of the colony, but the shift in two species that were uncommon in the area when the study began: the horned puffin and polar bear. The preliminary results from this summer show that hatching success (the number of eggs that hatched) was reasonably high at about 70 percent — but could have been over 80 percent had eggs not been displaced and broken by horned puffins pushing the eggs out of nest depressions and polar bears breaking the eggs by moving nest sites. Still, with over 180 guillemot chicks in nests in late July and early August, there was a good chance the colony could produce a sizable number of fledglings this year.

However,as August progressed the activities of puffins changed and visits by bears increased so that the number of guillemot chicks rapidly decreased to 100, and then to four chicks on August 16. While a few chicks died from lack of food or natural causes, the vast majority were the victims of puffins prospecting nest cavities and polar bears looking for food, with puffins killing (but not eating) about 80 chicks and polar bears killing (and sometimes eating) about 90. It is telling that the polar bear, an Arctic species forced south because of melting ice, and the horned puffin, a subarctic species moving north because of melting ice, could together cause the major breeding failure guillemots experienced this summer. While either species could have, by itself, greatly deceased breeding success, the combination proved devastating to the Cooper Island colony in 2009. A number of guillemot nests with two nestlings had young lost to both bears and puffins.

When I left the island late on August 17, one young guillemot had just fledged and there were three young still in nest sites, each with about two weeks to go before nest departure. It is likely that polar bear visits increased in frequency and duration after my departure, greatly decreasing the chances the three remaining chicks would successfully fledge.

Based on the frequency and activities of polar bears on Cooper Island in the last three years it appears likely that bears stranded on the beach looking for food will continue to cause major decreases in breeding success in the future. Surprisingly, it appears that non-breeding horned puffins, looking for nesting cavities and competing with guillemots for those cavities, could have an almost comparable impact on breeding success. Since the presence of both bears and puffins is related to the decrease in the ice extent and since there is no indication that the decrease in summer ice extent will reverse itself in the near future, both bear and puffin numbers on Cooper Island will likely increase in future breeding seasons.

Although the marine waters adjacent to Cooper are becoming more amenable to puffins, the establishment of a puffin colony on Cooper in the long-term will be prevented by the presence of polar bears that in recent years have preyed on puffin nestlings.

In the past week colleagues in Barrow and friends in Seattle have asked what the future of the guillemot colony is given this year’s observations. The short-term outlook is that breeding adults, with their high fidelity to nest sites, will continue to return to the colony even though breeding is likely to fail in most years because of bears and puffins. This lack of productivity will mean that, without immigration from other colonies, there will be no birds reaching breeding age and recruiting into the population. With overwinter mortality of breeding birds at approximately 15 percent and if no recruitment occurs, the colony will decrease in size by approximately 15 percent every year. This would mean that in 2025 the colony would be back down to ten pairs of guillemots, the same size it was in 1972 when I found it -– allowing me to exit saying “this is where I came in”.

Of course this assumes that the nest sites the bears destroy every year will be reconstructed to provide a nesting cavity and that some other factor doesn’t come into play. For instance, increasing erosion coupled with increasing storms and wave height may result in nest sites being washed away by late summer and fall storms.

While this assessment sounds gloomy it is also realistic, since the annual trend in summer ice extent leaves little doubt that there will be an ice-free Arctic sometime in this century. The number of polar bears forced to use the edge of the Arctic Basin as summering habitat will increase, and Cooper Island is one of the more logical places for them to aggregate on the Alaskan coast. And horned puffins will likely continue to visit Cooper Island in small numbers, drawn by the increases in subarctic fish in the region and a lack of suitable nesting cavities in the region.

The only way to know what will happen, of course, is to visit Cooper Island. And given this scenario, it is important to recognize the one certain fledge from the colony this year, since it may well be one of the last guillemots to fledge from the island. It survived a puffin visit that resulted in the death of its sibling and two bear visits that repositioned and almost destroyed the nest site where it was raised to fledging by its parents. If it can survive the next three years, it will likely return to Cooper Island for the 2012 breeding season. Even though the outlook for the colony is grim, seeing if that chick – the “Class of 2009” — does return will be enough to make me excited at the start of the field season three years from now.

I’ll have more thoughts on the field season, and the ongoing prospects for the colony, in the weeks to come. It looks to be a busy fall, with presentations as part of International Polar-Palooza, as well as places closer to home, and more analysis of the summer’s data and how it fits into the bigger picture on Cooper Island. Thanks to you who have followed the Cooper Island field season this summer. And special thanks to those who provided donations of moral,logistical and financial support allowing me to work on Cooper Island during this past field season. I plan to continue these posts here and on my website ( in the off season and hope you visit during the coming months.

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Back to Civilization

Cooper Island, Alaska, Aug. 22, 2009 — Last Monday evening near the end of a rainy stormy day, I called Lewis Brower, who would be my transportation to Barrow, to let him know that I hoped to see him on Wednesday when winds were predicted to be close to 10 mph. All day Monday wind speeds had been in the high teens and low 20s and from a direction that meant waves were breaking on both sides of the island. To my surprise Lewis told me he was getting his boat ready and would be on his way from Barrow in about half an hour. The sky, which had been dark gray most of the day, was starting to brighten to the west with blue patches contrasting sharply with the dark clouds. While winds were starting to slightly decrease there were still occasional 25 mph gusts and the weather service did not predict any change to occur until Wednesday.


I did not want to get my hopes up. After five weeks with only a single one-hour of direct contact with humans (when Ocean Watch stopped by for an hour to drop off the inverter), I was anxious to see and talk to most anyone. I was operating under the assumption that Lewis would likely not make it all the way to the island, but knowing that if he did I would have to be ready to leave. I started to dismantle and pack everything that had kept me alive and relatively happy for the previous two months. This meant taking down the wind generator, battery bank, propane stove, VHF radio and tower, computer connection to the satellite phone and antenna and storing and packing food and camping gear. I set to the side those things I would need to get me through the night if Lewis had to turn back. The latter consisting of a sleeping bag, shotgun with shells, a satellite phone, a small primus stove and a small amount of food. If I did not leave I would have to sleep in a corner of the cabin that had gone from my living quarters to a storage shed in less than two hours.

Against all odds at about 9 p.m., I saw Lewis’s boat coming through the waves and with his help the boat was loaded up and cabin boarded up within three hours. We left Cooper just as the sun was setting at 1130 p.m. and arrived in Barrow about two hours later. After almost five weeks alone it was good to see and talk with anyone, but especially good to see Lewis, who combines the skills and knowledge of someone who has lived his entire life in the Arctic with a positive attitude and sense of humor that is maintained in, apparently, most situations.

The following morning I awoke in Barrow to see that it was lucky we used the weather window we did since winds were again high. Just a few yards from my room the Chukchi Sea beach at Barrow was experiencing high surf. A storm a few weeks earlier had covered part of the beach road and this storm had waves crashing over the sand bags and piles of gravel that were reinforcing the beach.

After spending Tuesday morning dealing with the transition from the cold and solitary life I had on Cooper Island, I had lunch at Brower’s Café. The café dates from the late 19th century and is in the oldest framed building in the Arctic. It originally housed the Cape Smythe Whaling and Trading Company. It now has an arch made of two bowhead whale jawbones and two frames of umiaqs, the skin boats still used for spring whaling. While there are now a surprising number of restaurants in Barrow, only Brower’s Café with its history and view of the beach and ocean, provides its patrons with a sense of history and with a view that lets you know you are in the Arctic.

I am now back in Seattle and dealing with end of season logistics, but hope to have a post tomorrow about what happened with the guillemots, puffins and polar bears during my last days on the island. I have heard from a number of people who have asked how the guillemots did and want to pass on the good news that the first of the guillemots fledged on August 16, the offspring of Yellow-Black-Red and White-Gray-Brown. It left wearing the brown color band that will identify it as a member of the Class of 2009.

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Is It a Bird or a Bear?

Cooper Island, Alaska, Aug. 14, 2009 — This summer I find myself looking at images obtained over the past month on Cooper Island and thinking “what is wrong with these pictures?” But I know that the images of polar bears walking around the colony, sleeping on the beach and approaching the campsite, things I could never have imagined before 2002, are the product of habitat degradation rather than any image manipulation.

Because of the frequency and type of bear encounters in August 2008, I was looking for some way to have an alarm that would let me know a bear was approaching the cabin. This spring, when Marc Cornelissen, an Arctic researcher who has worked on Spitsbergen, a Norwegian island, offered to loan me some tripwire alarms I could use around the cabin, I eagerly accepted.

I had met Marc in April 2008 when he was mentoring a select group of European students who had been chosen to be “ambassadors” for the Ben and Jerry’s Climate Change College. Marc was touring Alaska with the students to allow them to see where climate change was most rapidly occurring. (Ben and Jerry’s funded the college in part with proceeds from the sale of a “Baked Alaska” ice cream that had the tagline “If it’s melted it’s ruined”. Unfortunately, this flavor is only available in the U.K. and Europe.) I spent a day with Marc and the students in Barrow, making a presentation to them about my findings on Cooper Island and listening to their questions and concerns about climate change in the Arctic.

Marc’s bear alarms arrived in a surprisingly small shipping container from Holland just as the field season began. The four alarms each consisted of a small plastic box, about the size of a cigarette pack, with carabiner (a clip with a spring) on two sides. One carabiner was attached to a pin inserted in the box, which triggered the alarm when pulled. When deployed, a taut string runs from the alarm’s pin to a post or other vertical structure. Increasing tension on the string pulls the pin and triggers the alarm in the box. The high pitched warbling alarm is surprisingly loud.

I set up the alarms this summer on the door and window sides of the cabin. Having tested each alarm by doing my imitation of how a bear might approach the camp, I did feel more confident when sitting in the cabin, and especially when falling asleep. Unfortunately, the tripwire lines attached to the alarms proved very attractive to the snow bunting adults and young that feed near the cabin. One of the shortcomings for birds on the island is a paucity of places to perch and it turns out that if more than two buntings sit on the string at the same time, they can pull the pin and set off the alarm. The first two times the alarms were triggered were during the day, and I emerged from the cabin with my shotgun at the ready (and adrenalin extremely high) to see a small flock of buntings flying away from the cabin — and from the high pitched alarm. It was good to know that my granola and oatmeal were safe from any seed-eating birds that might be considering a raid on the cabin. While it is true that the number of people killed by Snow Buntings in Alaska is just one less than the number killed by polar bears, to avoid such false alarms I started to deploy the alarms only as I was going to sleep.

Having the alarms was especially comforting last Friday night, since a bear had arrived on the island during a strong north wind that day. After nosing around a bit the bear had quickly gone to sleep behind a large box about quarter-mile from my cabin, so I turned in as well. At 4 a.m. Saturday morning, however, one of the alarms went off. I looked outside expecting to see the bear running from the cabin, but instead found it sniffing and licking the alarm. The bear only ran away when I shouted and made it aware that a human was in the cabin.

Later examination of nest sites and the bear’s tracks showed that it had walked through the colony turning over nests and eating guillemot chicks before approaching the cabin. The only reason I can think for the bear considering the alarm as food is that guillemot chicks do make noises when their nest sites are lifted, and the bear might have thought that the alarm was the world’s most high pitched and loudest guillemot chick.

Two nights later I had quite a different experience, which I was able to capture on the motion sensitive cameras I use for monitoring feeding activity and other nest activity. A bear that was not on the island when I went to sleep approached the cabin at 3:30 a.m. Upon triggering the alarm it turned and ran from the cabin. Here’s some primitive stills from the video — shot in infrared — of the bear-alarm encounter (the edge of my cabin can be seen along the left side).

So both times bears triggered the alarm, the alarms performed their function – which was to alert me to the fact that a bear was within 2 meters of the cabin. And now I know that when I hear an alarm I might look out to see a bear running away from the alarm – or I might see a bear trying to eat the alarm. And I suppose if I hear a high-pitched, warbling bear I will have the relationship to it that Captain Hook had to a crocodile that swallowed the clock.

The alarms were the only really positive part of the two visits by bears this past weekend. While the bears in mid July had little interest in just-hatched guillemots, chicks now apparently have enough fat and mass to be of nutritional interest to the bears. The strength of the bears, and their desire to get to the chicks,is obvious from the damage they did to nests.

Both bears had to swim through rather rough waters to reach the island, and sleep, rather than food, appeared to be their primary interest. One bear spent all day Saturday curled up in the driftwood, during a substantial rain storm. The other made a small depression behind a large box and spent all day Sunday sleeping out of the wind.

So thanks to Marc Cornelissen for allowing me to sleep a bit more soundly in the Cooper Island “Bird House” — and also thanks for his arranging to have the Ben and Jerry’s Climate Change College donate funds to partially fund this summer’s field camp. My next post will be the official “State of the Colony” address, as the first guillemot chicks are reaching the age to leave the nest.


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