Category Archives: An indicator of arctic change

Seabirds and Sea Ice

Over most of its range the Black Guillemot is a nearshore seabird, occupying coastal waters during both the breeding and nonbreeding seasons, as do other members of the genus Cepphus. Pelagic or open ocean waters can offer abundant prey resources, but these options are often distant, patchy and unpredictable.

The nearshore typically offers seabirds a smaller but more reliable source prey base consisting of forage fish and benthic fauna from the ocean floor such as crustaceans or mussels.

The Arctic Ocean has extensive sea ice cover in the nearshore for the majority of the year; this presents a number of challenges to a nearshore species. Our work on the Cooper Island Black Guillemots has revealed a number of ways in which the species has met these challenges.

The current view from my cabin window illustrates one of the major problems guillemots face in the Arctic. Sea ice extends from the north beach of the island to the horizon and covers Elson Lagoon to the south. The only water available to the guillemots is a brackish pond in the center of the colony that provides no prey but is deep enough to provide sanctuary if the guillemots need to dive when pursued by an owl or falcon — regular visitors to the island.

While guillemots arrived on the island almost a month ago and egg laying is now complete, until recently the closest predictable open water where guillemots could find prey was approximately 20 miles away, off Point Barrow where winds and currents shift the sea ice creating an area of open water. This opening is called a lead. The Cooper Island guillemots stage there in April and May before coming to the island. (Editor’s note: Leads are important for wildlife, because they allow for access to oxygen in the case of seals and walruses and prey in the case of seabirds; you can read more from the National Snow and Ice Data Center here.)

This distance between the Cooper Island guillemots’ nesting colony and access to their prey resources during egg laying and incubation is in sharp contrast to what guillemots breeding in subarctic or temperate waters find at their breeding colonies. These birds occupy waters directly adjacent to colonies well before egg laying and foraging areas may even be within sight of nests. The birds breeding on Cooper Island (and likely all colonies of Mandt’s Black Guillemot Cepphus grylle mandti, the high Arctic subspecies of Black Guillemot) have responded to this spatial disconnect by having a well-defined periodicity in their daily colony attendance. Every day, the parent not incubating eggs and all nonbreeding individuals vacate the colony from approximately noon until midnight. The birds fly individually or in small groups to open water where they can feed for almost half the day before returning to the colony just as the “midnight sun” is at its lowest point in the sky.

MODIS image from July 9; snow and ice have blue/cyan color, while clouds will be lighter gray/white. Image Credit: David Douglass/USGS

While it seems individual birds could fly offshore to open water to feed anytime during the day, there are a number of possible reasons the observed colony-wide pattern of attendance and abandonment developed. For the half of the day when the guillemots are absent – from approximately noon to midnight – there is no evidence that Cooper Island supports a colony of Black Guillemots. It appears to be just a barren sandbar that happens to inexplicably have 200 scattered black plastic cases along with a small cabin surrounded by a bear fence. Falcons, Snowy Owls, and other predators moving along the barrier islands would have little reason to be attracted to this place.

The timing of the birds’ departure and return may be related to changes in air temperature and its effect on ice formation. On nights when the air temperature is below freezing (as it was last night), I have frequently observed the formation of new ice on the surface of the few spaces of open water in the sea ice directly adjacent to shore. This newly formed ice melts in the morning as air temperatures rise. Nocturnal formation of new ice in the waters adjacent to the pack ice reduces the amount of open water available for guillemots to dive for the prey.

This temporary daily reduction in foraging area could be expected to have been pronounced during the Last Glacial Maximum when air temperatures were lower and the ancestors of the Cooper Island guillemots occupied an Arctic refugium. The current pattern of colony attendance for the Cooper Island colony – foraging during the warmest part of the day and attending the breeding colony at night – could have evolved as a way of maximizing the amount of open water available for guillemots.

The large expanse of shorefast ice north of the island this year is persisting later than expected compared to recent years. While the nearshore ice may now be forcing the Cooper Island guillemots to fly further in search of prey, it could benefit the colony later this summer should ice remain in the nearshore close to the colony. In recent years a lack of sea ice when the guillemots are feeding young resulted in increased nestling mortality as higher sea surface temperatures reduced the availability of Arctic Cod, the guillemots’ preferred prey.

Should this year’s nearshore ice break up slowly over the next month, Arctic Cod could remain in the guillemots’ foraging range and allow increased chick growth and fledging success. The latter is urgently needed for the colony to reduce its current population decline. First eggs will be hatching in about two weeks and our daily weighing of nestlings and prey observations should demonstrate how much this year’s persistent sea ice has affected the guillemots’ nearshore environment.

Work Worth Doing: Reflecting on 44 years in the Field

The Cooper Island Black Guillemot study was recently mentioned in an Associated Press story by Seth Borenstein about researchers who “accidentally” began studying climate change. A number of scientists measuring a biological phenomenon have encountered unanticipated effects from climate change and understood those effects were more important, both biologically and politically, than what originally motivated them to initiate their research. The 44-year Cooper Island study has undergone a number of changes before its current focus on assessing the decadal effects of Arctic warming on seabirds.

When I first landed on Cooper Island in 1975, I had no intention of studying climate change or global warming.

Neither the globe nor the Arctic had warmed in the decades immediately preceding the start of my study. Research at the Cooper Island Black Guillemot colony started as part of a large federal program assessing Alaska’s then largely unknown marine ecosystems in anticipation of leasing offshore waters for oil development. Cooper Island was the furthest north of many seabird colonies in coastal Alaska where biologists documented the extent and basic biology of the state’s seabird resources in the late 1970s. When that program ended in 1981, due to a change of administrations and a less urgent need to move forward with offshore drilling, it had provided sufficient information for the drafting of environmental impact statements.

In 1982, lacking federal funding, and possibly more importantly logistical support, I made the decision to return to Cooper Island to continue the Black Guillemot study. I had developed a real attachment to northern Alaska with its field seasons of 24 hours of daylight and sea ice always visible just offshore. Through annual banding of breeding birds and their nestlings in the late 1970s, I had developed a population of largely known-history and known-age seabirds. I was initially drawn to the study of seabirds having read the works of British ornithologists conducting multi-year studies at a single colony and documenting the life histories of individual birds. Such work is beyond the scope and timeframe of pre-development environmental assessments and of federal agencies, with their frequently shifting agendas.

Only in the third decade of research was there an indication that increasing atmospheric temperatures were affecting the Black Guillemot colony. Earlier snowmelt in the 1990s allowed earlier initiation of breeding. Climate change impacts rapidly increased in the 21st Century as decreasing sea ice and increasing sea surface temperatures reduced the guillemots’ preferred prey and greatly reduced breeding success. The least nuanced sign of Arctic warming, polar bears stranded on the island approaching our field camp, began in 2002 and this will certainly occur again this summer.

While monitoring the effects of climate change will continue to be the focus of the work, the study is now proceeding in ways never anticipated in 1975. Since 2011, we have deployed biologgers on the bands of guillemots to measure diving behavior during breeding and location and activity of birds during the nonbreeding season. That work is being continued and analyzed as part of the Sentinels of Sea Ice (SENSEI) project, which this fall will have our collaborators from France’s National Center for Scientific Research (CNRS) hiring a post-doc to examine our demographic database.

Vicki Friesen of Queen’s University in Kingston, Ontario has a graduate student, Drew Sauve, examining the genetics of individual guillemots and the heritability of the metrics we have obtained on breeding biology.  Drew recently completed a master’s degree on the heritability of timing of egg laying and is beginning a doctoral program utilizing the Cooper Island colony and database. He will be joining me on the island later this month to gather additional genetic material.

As I walked around the colony this past week in this 44th year of the study, determining nest ownership and dates of egg laying, it is extremely satisfying to know the data is part of a data set spanning six generations of guillemots and can provide unparalleled insights into the biology of an Arctic seabird experiencing a rapidly changing environment.

Cooper Island Research Part of SENSEI: Sentinels of the Sea Ice

In 2015 Christophe Barbraud of the Centre d’Etudes Biologiques de Chizé began assisting us with the analysis of the four-decade demographic database we have obtained from the Cooper Island Black Guillemot colony.  Christophe is a highly respected avian demographer whose study species include the Snow Petrel, an ice-obligate Antarctic seabird, as well as a number of other seabirds.  We were fortunate to have him appreciate the potential and uniqueness of our long-term databases and show an interest in our work.

Our collaboration has led to the Cooper Island Black Guillemot study being part of the recently initiated project Sentinels of the Sea Ice (SENSEI) funded by the BNP Paribas Foundation. Their Climate Initiative program funds work that will improve our understanding of climate change, inform and mobilize citizens and, ultimately,  assist in political decisions and solutions.   While our participation in SENSEI will not assist us with the logistics of our field season and maintaining the long-term database, it will greatly facilitate data analysis and outreach efforts.

Comprised of 13 teams of researchers from six countries, the project will assess recent and ongoing responses of ice-associated seabirds and seals to changes in Arctic and Antarctic sea ice. The  “sentinel species”  being studied other than the Black Guillemot are the Thick-billed Murre, Black-legged Kittiwake and Hooded Seal in the Arctic and  Snow Petrel,  Adélie penguin, Weddell Seal and Elephant Seal in the Antarctic.  The project’s official website has background on the study species, researchers and plans – including development of an educational platform in 2018 that will promote the scientific and conservation aspects of the project and is being developed with Luc Jacquet, who directed March of the Penguins.

BNP Paribas webpage devoted to the project  provides background and why they chose to fund SENSEI as part of their effort to address climate change.  The site includes a video (above ) with a great animated cartoon Black Guillemot –  who seems unaware that some might find him less charismatic than the ever-popular penguin.

Last month I visited Christophe and Yan Ropert-Coudert, the project’s other Principal Investigator, at their research center in Chizé, France to discuss the  role of the Cooper Island research in the project and outline strategies for analyzing our 43 years of data.  Will be posting more about this exciting opportunity as our plans develop.