(Photo by G. Fernandez Aceves)
Title
of thesis:Foraging ecology and
site selection in Western Sandpipers during their fall migration through
southwestern BC
Supervisor:Ron
Ydenberg
Short
biography:
Grew
up out in the sticks east of Seattle, Washington.Got
pulled over a lot in high school.Started
at University of Washington in 1990.Hung
in there for two B.S. degrees:Oceanography
and Biology II (Ecology).Met a cute
girl (Katrina) in Geology 205.Worked
at a Vespa repair shop and the Pacific Science Center in Seattle.Drove
all over North America in a '65 VW bug in 1995 with cute girl from Geology
205.Married in 1998, moved to BC
and started grad school.Recently
moved to Santa Cruz, California, where Katrina is starting her Ph.D. and
I am writing up my M.Sc. thesis.
Summary
of current research:
The
goal of my project was to determine (1.) what juvenile Western Sandpipers
are eating when they forage on two mudflats near the Fraser River estuary
in British Columbia, and (2.) whether the mass gain rate while foraging
differs between the sites, which are Sidney Island and Boundary Bay.
To
identify prey types, mud and poop samples collected in precise locations
where birds had been feeding were analyzed using a dissecting scope.Corophium
and other amphipods rank among the most important prey types.Within
this genus, only individuals 2.75 to 4.75 mm long were consumed.Other
crustaceans, snails, bivalves, polychaetes, and foraminifera were also
apparently taken.
To
compare mass gain rate between sites, sandpipers were captured and allowed
to feed within a floorless mesh enclosure on one mudflat or the other.Birds
were weighed repeatedly before and after foraging, and mass gain was estimated
as the difference between the intercepts of the "before" and "after" mass
trajectories.On average, mass gain
rates were 0.3 g/h higher on Sidney Island (by ANCOVA, with initial mass
as the covariate, p=.0214, n=4,5), with a maximum around 0.75 g/h.These
results are preliminary because the sample size was small, and because
we don't yet know the extent to which the mass gained represents assimilation,
rehydration, or retention of gut contents.
This
project is part of a bigger study which aims to determine why individual
sandpipers choose one mudflat over another.Other
factors the birds must consider include local weather conditions and the
probability of being killed by Peregrine Falcons and similar predators.
Previous
research:
Intertidal
invertebrate fauna at Seattle's Discovery Park
Color
change in Idotea wosnesenskii, a marine isopod
Financial
support for M.Sc. research:
NSERC
through Ron Ydenberg
Acknowledgements/collaborators:
Field
support - Moira Lemon, James Burns, Silke Nebel, David Seay, Kina Harrington,
Andy Davis, Rob Butler, Gary Burness, Will Stein, Darren Lissimore &
his dad, Casey Ydenberg & his dad, Dov Lank, Jessica MacDonald, Kyle
& Matthew.Other support - Ydenberg
lab, Chris Guglielmo, Leslie Kristoff, Bob Elner, Tony Williams, Alex Fraser,
Darren Witt, CWS in general, and Katrina Dlugosch.
Recent
Publications/presentations:
Ydenberg,
R.C., R.W. Butler, D.B. Lank, C.G. Guglielmo, M. Lemon, and N. Wolf. Trade-offs,
condition dependence and stopover site selection by migrating sandpipers.
Submitted to Journal of Avian Biology.
Foraging
ecology of juvenile Western sandpipers in southwestern BC during their
first fall migration
(Presentation,
2000 Western Sandpiper meeting at SFU)
Modeling
the effects of predator behavior on prey behavior, and vice-versa:Mortal
enemies negotiate a compromise
(Presentation,
SFU's "Les Ecologistes" seminar series, October 2000)