Seabird Telemetry 2009
As they did in 2008, Bering Sea Project seabird telemetry crews tracked black-legged kittiwakes and thick-billed murres that were raising young on St. Paul and St. George islands in 2009 to learn more about their foraging patterns offshore.
Another challenging year
The 2009 breeding season was another challenging year for place-based foragers in the southeastern Bering Sea. Another oddly cold summer meant poor nesting success for piscivorous seabirds such as murres and kittiwakes, especially black-legged kittiwakes (left). Many kittiwakes started abandoning their nesting efforts late in June, during the incubation period.
As in 2008, there was almost no overlap in the foraging locations between seabirds nesting on the two Pribilof islands in 2009, regardless of species. Seabirds nesting on St. George Island, both kittiwakes and murres, commuted longer distances to forage than their St. Paul Island counterparts.
Right: GPS foraging tracks of thick-billed murres (above right) and black-legged kittiwakes (below right) nesting at either St. Paul Island or St. George Island during July-August 2009. Note the extremely clear between-island separation in foraging areas for both kittiwakes and murres. Click each image to see a larger version.
St. Paul birds foraged in relatively shallow water over the continental shelf, while St. George birds headed to waters over the steep shelf break and the deep waters beyond to forage. Not surprisingly, diet composition differed between the two islands, both for kittiwakes and murres (left).
What is surprising is the distinctly different foraging ecology of birds nesting on the two islands, which are separated by only 65 kilometers, well within the foraging range of either seabird species.
about the colored lines
Each color-track line represents a tremendous amount of effort and patience in order to recapture birds with GPS loggers that, in many cases, were nearly impossible to recapture.
What’s behind these changes in foraging behavior?
The most obvious difference in foraging behavior between 2008 and 2009 is for black-legged kittiwakes nesting on St. Paul Island.
In 2008, they either foraged very close to St. Paul Island, headed up on the shelf to the north, or went long-distance to the southwest toward and beyond the shelf break. In 2009, their foraging tracks are mostly to the northwest of St. Paul Island, where no kittiwakes were tracked in 2008.
Below right: Track comparisons for 2008 and 2009 combined in single images. Click each image for a larger version.
Why the difference? That area to the northwest of St. Paul was a hotspot for age 1+ walleye pollock in 2009; 1+ pollock were very scarce anywhere near the Pribilof Islands in 2008. Note also that the kittiwakes nesting on St. Paul found the concentrations of 1+ pollock to the northwest, but the kittiwakes nesting on St. George didn't; no St. George kittiwakes used the main foraging area for St. Paul kittiwakes in 2009.
This work integrates results of two projects: Seabird telemetry and At-sea Patch Dynamics.
Learn more about 2008 At-sea Patch Dynamics fieldwork
Kudos to the field crews
The success of the 2009 season was due to the excellent dedication, work, and enthusiasm of the field crews. Each color-track line in the figures above represents a tremendous amount of effort and patience in order to recapture birds with GPS loggers that, in many cases, were nearly impossible to recapture.
Right: The F/V Gold Rush made a port visit to St. Paul, and met up with the on-island bird and mammal crews. (Scott Heppell) See larger image
At St. Paul Island, Rachael Orben (Crew Leader) teamed up with Dan Cushing (Seabird Telemetry Tech), John Warzybok (Refuge Biologist), and Tom Harten (PolarTREC teacher). At St. George Island, Rosana Paredes (Project Leader) teamed up with Robert Massengale (Seabird Telemetry Tech), Brie Drummond (Refuge Biologist), and Dean Kildaw (Seabird Telemetry Tech Extraordinaire).
Tom Harten: teacher at sea
Maryland teacher Tom Harten (right) was on this season's seabird telemetry expedition as part of the PolarTREC program. See Tom's Journal and Photos
PolarTREC was created by ARCUS and funded by NSF to facilitate participation of K-12 teachers in polar research. Teachers work closely with scientists as a pathway to improving science education. This program builds on outstanding scientific and cultural opportunities in the Arctic and Antarctic to link research and education through intriguing topics that will engage students and the public. Find out more about PolarTREC and connect with other teachers who have participated in Bering Sea Project fieldwork.
The BEST-BSIERP Bering Sea Project is a six-year study of the Bering Sea ecosystem,
from the benthos and the atmosphere to human communities, and everything in between.
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