abstracts of oral and poster presentations - Pacific Seabird Group

velocity core of the Equatorial Undercurrent (EUC) that flows unimpeded for over a thousand miles before
striking the subsurface of Jarvis. This submarine current surfaces cold, nutrient-rich water to where
zooplankivorious Blue Noddies and other marinelife benefit. Feral cats, as top food chain carnivores, previously
masked the terrestrial expression of this phenomenon. The relatively high numbers of Blue Noddies, one of the
highest densities in the world, and the observation that Jarvis was one of the most productive guano islands
during that period of exploitation, is now apparent as oceanographic processes are better appreciated. Insights
like these help direct future eradication work where local oceanographic conditions are amenable for enhanced
restoration values.
ISLAND RESTORATION AND ENHANCEMENT: SUCCESSES, FAILURES, AND TOOLS FOR THE
21 ST CENTURY
Mark Rauzon 1 and Bradford Keitt 2 ; 1 Marine Endeavours, Oakland, CA; 2 Island Conservation, University of
California, Santa Cruz, CA
[No abstract was received]
COUNTING THE COUNTLESS: ESTIMATING THE SIZE OF AUKLET COLONIES [Poster]
Heather M. Renner 1 (heather_renner@fws.gov) and Martin Renner 2 ; 1 Alaska Maritime National Wildlife
Refuge, Homer, AK USA; 2 Memorial University of Newfoundland, St. Johns, NF CANADA
Least Auklets are likely the most abundant nesting seabird in the North Pacific, but population estimates
have been largely conjectural and highly variable among observers. The difficulty in accurate estimation results
from erratic attendance of birds at colonies and numbers often too large to count accurately. We developed a
new technique for estimating colony size from spatial density and presence/absence data collected in a
randomized grid survey of colony extent and applied the technique at St. George Island, Alaska, in June 2004.
The colony was surveyed systematically for indirect evidence of nesting density, and we translated relative
densities into absolute densities using attendance counts including a known population of color-banded
individuals. Birds present on the surface of the nesting colony were counted on 14 plots on three different days
during the incubation period. We predicted density of birds attending the surface of the colony from counts of
feathers and droppings on sampling plots. Mark-resight data were used to estimate the proportion of birds living
on a plot that were observed during our surveys. We used spatial interpolation to estimate auklet density, and
we present the first population estimate for any auklet colony that is based on repeatable, georeferenced spatial
data.
EFFECTS OF OIL EXPOSURE ON ENERGETICS OF CAPTIVE HARLEQUIN DUCKS
Daniel J. Rizzolo 1 (drizzolo@usgs.gov) and Daniel Esler 2 ; 1 Alaska Science Center, US Geological Survey,
Anchorage, AK USA; 2 Centre for Wildlife Ecology, Simon Fraser University, Burnaby, BC CANADA
Harlequin Ducks wintering in areas of Prince William Sound (PWS), Alaska, contaminated by the 1989
Exxon Valdez oil spill showed elevated levels of CYP1A, an enzyme induced upon exposure to hydrocarbons, 9
years after the spill. However, effects of exposure on individual health are poorly understood. One potential
consequence of oil exposure is an increase in metabolic costs. Because Prince William Sound is near the
northern range limit for Harlequin Ducks, any additive energy demands related to exposure to oil could affect
survival. To evaluate the hypothesis that exposure to oil increases energy demands in Harlequin Ducks, we
measured oxygen consumption, daily energy expenditure (DEE), and food consumption of captive Harlequin
Ducks in controlled oil-dosing and plumage-oiling experiments. Although CYP1A was induced in oil-dosed
birds, we found no differences in oxygen consumption, DEE, or food consumption between dosed and control
treatments. However, plumage-oiling increased oxygen consumption and DEE. These results suggest that
plumage-oiling would have stronger effects on energetics than oil ingestion for birds wintering in oilcontaminated
areas of PWS, if long-term external exposure was occurring. Further, although induction of
CYP1A indicates hydrocarbon exposure, our results suggest it is not necessarily associated with increased
energy requirement if the route of exposure is ingestion.