abstracts of oral and poster presentations - Pacific Seabird Group

FORAGING BEHAVIOR OF MARBLED MURRELETS: MEETING REPRODUCTIVE DEMANDS IN A
DYNAMIC OCEAN ENVIRONMENT
M. Zachariah Peery 1 (zpeery@nature.berkeley.edu), Steven R. Beissinger 1 , and Scott H. Newman 2 ;
1 Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA USA;
2 Wildlife Trust, Palisades, NY USA
We used radio-telemetry to investigate how a pursuit-diving seabird, the Marbled Murrelet
(Brachyramphus marmoratus), adjusts the effort it devotes to foraging in response to breeding commitments and
physical oceanographic factors that affect prey availability in central California. Radio-marked murrelets (n =
32) spent more time diving during upwelling events than during relaxation events,; as upwelling events became
longer, murrelets traveled shorter distances to foraging locations. The duration of dive bouts was greater during
rough sea conditions than during moderate and calm conditions, and both the proportion of time spent diving
and the duration of dive bouts declined as the breeding season progressed. Actively nesting birds (1) spent more
time foraging than nonbreeders and breeders that were not nesting; and (2) reduced the distance that they
traveled from nesting to foraging sites. In general, murrelets increased the effort they devoted to diving and
conserved energy by reducing the distance they traveled to foraging sites when reproductive demands were high
or food availability, as indexed by physical oceanographic conditions, was low. In particular, we suggest that
murrelets foraged more during upwelling events due to the advection of prey from nearshore waters and that
murrelets restricted their movements as upwelling events became longer to avoid wasting energy searching for
depleted prey. Although murrelets adjusted their foraging behavior in response to both breeding commitments
and oceanographic conditions, breeding commitments appeared to play a more important role in determining
feeding strategies.
BACKGROUND ON THE 5-YEAR REVIEW AND THE U.S. FISH AND WILDLIFE SERVICE DECISION
Paul Phifer (paul_phifer@r1.fws.gov) and Lee Folliard; US Fish and Wildlife Service, Portland, OR USA
On September 1, 2004, the U.S. Fish and Wildlife Service completed its formal 5-year review of the
Marbled Murrelet, concluding the population of murrelets in California, Oregon, and Washington does not
satisfy the criteria for designation as a Distinct Population Segment (DPS) under the Service’s 1996 DPS Policy.
The Service’s analysis concluded there is no marked separation of physical, physiological, ecological, or
behavioral differences at the U.S. and Canadian border, and no significant evidence of genetic or morphological
discontinuity between populations at the border. The results also show that there are no differences in control,
exploitation, management of habitat, conservation status, or regulatory mechanisms across the international
border that are significant. While the California, Oregon, and Washington population does not qualify as a DPS,
the question of whether the three-state population constitutes a significant portion of the range of the species, or
whether the species as a whole is at risk of extinction, still needs to be addressed before any change in the listing
status occurs. Delisting or reclassifying the murrelet under the Endangered Species Act will require a separate
rulemaking, involving public notice and comment.
LARGE-SCALE MOVEMENTS AND HABITAT USE OF KING EIDERS THROUGHOUT THE
NONBREEDING PERIOD
Laura M. Phillips* (fslmp@uaf.edu) and Abby N. Powell; Alaska Cooperative Fish and Wildlife Research Unit,
University of Alaska, Fairbanks, AK USA
King Eiders molt wing feathers and overwinter in remote areas of the Bering Sea, precluding direct
observation of the birds at this time. To characterize the timing of migration and habitat used by King Eiders
during the non-breeding period, we derived the location data of 60 individuals (27 females and 33 males) from
satellite telemetry and oceanographic information from remotely sensed data. Male King Eiders dispersed from
breeding areas earlier, arrived at molt sites earlier, and remained at molting locations longer than females.
Males that arrived at molting sites earlier molted at higher latitudes. King Eiders that wintered farther south
returned to breeding areas earlier the following summer. Distributions of molting and wintering locations did
not differ by sex, year, or capture location. General linear models suggest that the variables distance to shore,
water depth, and salinity best describe King Eider habitat throughout the non-breeding period. During the