Journal Entry
Bingo! Researcher Jim Lovvorn of the University of Wyoming saw two Spectacled Eiders (Somateria fisheri) flying low to the Northeast. I was with Dr. Lovvorn in a Bell Ranger helicopter flying on a Spectacled Eider survey south of St. Lawrence Island in the north Bering Sea on Wednesday, March 19, 2008. We were on our last transect of the night. We followed the birds for about a half-mile, until they dipped down lower to a large open lead. We lost them in the background of the open water. Even though we lost track of the two birds, our spirits were high.
Spectacled Eiders south of St. Lawrence Island in the Bering Sea.
Dr. Lovvorn has been conducting surveys in the north Bering Sea throughout our science expedition. Spectacled Eiders in the winter are a mystery to the scientific community. Their fall and winter distributions were unknown until it was discovered in 1995 that they wintered in the Bering Sea between St Matthew and St Lawrence Islands. They have three primary nesting grounds in SW Alaska, the arctic coastal plain of Alaska, and the arctic coastal plain of Russia. Historical data on the Spectacled Eiders is scarce, however, research on the Yukon Delta Wildlife Refuge suggest that the breeding population has declined by 96%. Only 4,000 breeding pairs continue to nest there. On the Alaska arctic plain, approximately 4,000 breeding pairs nest during the spring and summer and on the Russian arctic plain, it is estimated that over 40,000 breeding pairs arrive in the spring. Including non-breeding birds, the Spectacled Eiders world-wide population is about 360,000 birds.
<figure class="standalone-image" style="display:block;"><img src="/files/members/craig-kasemodel/images/03202008009spectacledeiders.jpg" alt="Spectacled Eiders in Flight" title="Spectacled Eiders south of St. Lawrence Island in the Bering Sea." width="640" height="360" /><figcaption class="caption" style="display:block">Spectacled Eiders south of St. Lawrence Island in the Bering Sea.</figcaption>
In 1993, Spectacled Eiders were listed as a threatened species under the US Endangered Species Act. In 2007, the North Pacific Fishery Management Council established the Northern Bering Sea Research Area (NBSRA). The NBSRA closed the area to bottom trawling by the commercial fishery until areas are identified to protect species of concern, such as the Spectacled Eider, and assessments on the effects of bottom trawling.
<figure class="standalone-image" style="display:block;"><img src="/files/members/craig-kasemodel/images/03202008014spectacledeiders.jpg" alt="Spectacled Eiders" title="Spectacled Eiders south of St. Lawrence Island in the Bering Sea." width="640" height="360" /><figcaption class="caption" style="display:block">Spectacled Eiders south of St. Lawrence Island in the Bering Sea.</figcaption>
Spectacled Eiders are large diving sea ducks. Males have a black chest, white back, a green head, and a white patch around their eye that resemble eyeglasses. Their diet consists of aquatic animals gathered from bottom sediments, mainly mollusks and crustaceans, aquatic insects, and some vegetation.
Dr. Lovvorn's research has concentrated on the bioenergetics of the Spectacled Eider and the effects of climate change and warming waters on the Spectacled Eiders in the Bering Sea. He has found that 90% of the Spectacled Eiders diet consists of one species of mollusks, *Nuculana radiata*, a small clam in the benthic environment of the Bering Sea. The Spectacled Eiders seem to select for *Nuculana *in the 18-24 mm size. It is the most abundant size class providing the eiders with the most biomass and energy. The sea ducks are capable of diving up to 70 m to forage.
Dr. Lovvorn's research has shown that they are efficient divers. The energy
costs to the sea ducks while they are diving are lower than if they are swimming on the sea's surface. Swimming takes more energy staying warm on the water than diving when they use the wings and legs to generate heat. Sitting on the ice edge at a lead in the sea ice, requires less energy due to the fact that they are not losing heat to the water relative to the ice.
<figure class="standalone-image" style="display:block;"><img src="/files/members/craig-kasemodel/images/03202008025spectacledeiders.jpg" alt="Spectacled Eiders taking flight from a lead" title="Spectacled Eiders south of St. Lawrence Island in the Bering Sea." width="640" height="360" /><figcaption class="caption" style="display:block">Spectacled Eiders south of St. Lawrence Island in the Bering Sea.</figcaption>
Dr. Lovvorn will utilize eider locations and abundance data to compare it with the benthic and water sampling data. If the waters of the northern Bering Sea are indeed warming, there could be several effects to the Spectacled Eider's long-term viability. There could be increased interspecific competition for their primary food source if warmer water species move into the area. Their primary food source population could decline due to changes in the water chemistry and nutrients released from the algae in the sea ice, resulting in increased intraspecific competition between the eiders for a smaller prey base. Dr. Lovvorn is trying to model the extent and location of habitat of the Spectacled Eider where they can maintain a positive energy balance and maintain a viable population.
Shortly after watching the two eiders disappear into the background of the lead's dark waters, we remained on course of the line transect. We had only a few more miles to cover before the survey was completed. Suddenly, seemingly out of nowhere, thousands of Spectacled Eiders appeared below us and in front of us. Waves of birds took flight and thousands more remained on the edge of the ice at several leads. Dr. Lovvorn found a concentration of birds that he estimated to be over 8,000 birds. I took several minutes of video while the birds where in flight. It was quite a sight to behold with the streaks of light off in the horizon.
<figure class="standalone-image" style="display:block;"><img src="/files/members/craig-kasemodel/images/03202008031spectacledeiders.jpg" alt="Streaks of light on the horizon" title="The Bering Sea near St. Lawrence Island." width="640" height="360" /><figcaption class="caption" style="display:block">The Bering Sea near St. Lawrence Island.</figcaption>
During our next couple of days, while the ship was traveling to the day's scheduled sampling stations, the science expedition has encountered large flocks of the Spectacled Eiders numbering in the thousands. The data gathered by each of the scientist's will be important in the context of the knowing the patch dynamics of the Bering Sea ecosystem. What will be the fate of the Spectacled Eiders in the long run? The Bering Sea Ecosystem Study and the Bering Sea Integrated Ecosystem Research Program will be examining this question among others for the next six years.