abstracts of oral and poster presentations - Pacific Seabird Group

Twitter and Chick Peers), plus one non-vocal sound (Bill-clapping). Most vocal activity is nocturnal and confined
to staging areas near the colonies. Chicks are raised for 2–3 days in the burrow, fledge, and then must reunite with
their parents at sea for continued care. Vocal recognition probably drives this reunification and has been found in
related alcids. If individual vocal stereotypy could be readily detected, it could be exploited to improve censusing or
population-monitoring efforts. Without visual confirmation, individuals were determined circumstantially (multiple
calls from fixed location). Captive recordings of two chicks were also made and their Peer calls assessed for
individuality. Potential for vocal individuality was found in both the adult and chick calls by all methods (visual
sorting of sound spectrograms/amplitude envelopes, multidimensional scaling, and cluster analyses), but
methodological refinement is necessary for this to be a practical management tool. Chick Peer calls unexpectedly
showed dual voicing (resonance of sound from two parts of the syrinx), a first for the Alcidae, which might be
important for recognition.
THERE IS A SEASON, TERN, TERN, TERN: ARCTIC TERN POPULATION VIABILITY IN THE GULF
OF MAINE
Catherine M. Devlin* 1 (i65v9@unb.ca), Antony W. Diamond 1 , C. Scott Hall 2 , Stephen W. Kress 2 , and Linda
Welch 3 ; 1 University of New Brunswick, Frederickton, NB CANADA; 2 National Audubon Society, Ithaca, NY
USA; 3 U.S. Fish and Wildlife Service
While no population viability model can predict the future accurately, each model can help managers
focus research efforts and management techniques. Arctic Terns in the Gulf of Maine are part of a structured
regional population, with nesting colonies concentrated on a few managed islands. In 1999, we initiated a
banding and resighting study to examine this species. We have used capture-mark-recapture analysis of banded
individuals to develop and examine the first estimates of survival and movement of Arctic Terns banded as
chicks and as adults in North America. Using these data and estimates of fecundity, we examined the viability
of the population. Our analysis indicates that, if current trends in productivity, survival, and movement
continue, the population may experience fluctuations but will remain relatively steady within the region.
However, Peregrine Falcons have increased in number within the region and in the frequency of visits to some
colonies and may play an increasingly important role in the survival of the terns. There has also been wide
variation in the diet of the nesting terns. These factors, in terms of increased predation on terns and potential
food limitations, could play a larger role than before in the future of this species within the region.
THE DEMOGRAPHIC RESPONSE OF BLACK GUILLEMOTS TO A SHIFT IN THE ARCTIC
OSCILLATION
George J. Divoky 1 (fngjd@uaf.edu) and Katie Dugger 2 ; 1 Institute of Arctic Biology, University of Alaska,
Fairbanks, AK USA; 2 Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR USA
The Black Guillemot is a high-arctic seabird that relies heavily on the sympagic food web associated
with pack ice. In the western Arctic, a shift from a cold to a warm phase of the Arctic Oscillation (AO) in 1989
resulted in major decreases in the pack-ice habitat that provides Black Guillemots its primary prey of arctic cod.
A guillemot colony in northern Alaska, studied annually since 1975, has shown the impacts of this shift in a
number of demographic parameters. The breeding population decreased from just over 200 pairs in the late
1980s to 120 pairs in 1997. Breeding success averaged >50% before 1989 but since has decreased to