note: Grad student Zach Peery will
be filing regular dispatches from the field this summer. We'll
publish his reports online here. This is Zach's first report.
NUEVO, CALIFORNIA -
The Marbled Murrelet is a highly endangered seabird in California,
so much so that is listed as an Endangered Species by the
California Department of Fish and Game and as a Threatened
Species by the U.S. Fish Wildlife Service.
bird is unique within its family (Alcidae) in that it nests
solitarily on the large, moss-covered limbs of large trees
in old-growth redwood forests. Most other alcids nest in
groups, colonially or semi-colonially, on coastal cliffs
or rocky offshore islands. A variety of environmental factors
threaten the murrelet or have contributed to historic declines
in California. They include the harvesting of old-growth
nesting habitat, oil spills, gill-netting, nest predation,
anthropogenic disturbance at nest sites, and warming trends
and contaminants in the marine environment.
the supervision of Dr. Steven Beissinger of the Dept. of
Environmental Science, Policy and Management, I am studying
the southernmost Marbled Murrelet population. They nest
in the coastal redwood forests of the Santa Cruz Mountains
and spend most of their time at sea in the near-shore areas,
diving and pursuing small fish such as sandlance, northern
anchovies, and sardines.
research conducted by Beissinger and his former graduate
student Ben Becker indicates that only about 500 murrelets
remain in central California. The next closest population
is located off of the Humboldt County coast in northern
California and is part of the controversy surrounding the
recently acquired Headwaters Grove. Apparently populations
historically located off of Marin and Sonoma County coasts
have been almost completely extirpated. Because of its isolation,
our study population may be genetically distinct from other
murrelet populations and constitute an "Evolutionary
Significant Unit". If so, conserving this population
will be critical for maintaining the genetic diversity of
this species as well as its future evolutionary potential.
Marbled Murrelet is an extremely secretive bird. It generally
attends its nest site before sunrise and after sunset, does
not vocalize near its nest, and nests approximately 200
feet up in the tallest trees in the world. This secrecy
makes the murrelet nests exceptionally challenging to find.
In fact, the murrelet was the last bird for which a nest
was a located. At one point, the Audubon Society actually
offered a bounty to the first birder who could locate a
murrelet nest. It was not until 1974 that a nest was found
in Big Basin State Park in the Santa Cruz Mountains. The
bird's secretive behavior also makes it an extremely challenging
study organism from a dissertation perspective. Nevertheless
due to recent methodological advances in captures, radio-telemetry,
and genetic techniques, we are beginning to gain insight
into the life history of murrelets that previously would
not have been attainable.
overarching goals of my dissertation research is to: (1)
determine if the Marbled Murrelet population in central
California is declining; (2) determine which environmental
factors are responsible for the declines; and (3) and develop
management recommendations that will help recover murrelets
study can be divided into four different components that
reflect different aspects of murrelet ecology and involve
different field techniques. They include:
Patterns: I am using radio-telemetry to investigate
both the breeding season and migratory movement patterns
of murrelets in central California. Increasing our understanding
of what at-sea areas murrelets use is important for estimating
and minimizing the impacts of oil spills.
Ecology: I am radio-marking individual murrelets and
tracking them back to their nest sites. In doing so, I am
able to determine which murrelets are nesting, where they
are nesting, how many nests fail, and why nests fail. Because
of their secretive life history, radio-telemetry is the
only effective way to locate significant numbers of nests.
Assessment: I am conducting at-sea surveys from Half-Moon
Bay to Santa Cruz to estimate changes in the number of murrelets
from year to year. I am also catching and banding individual
murrelets to estimate mortality and recruitment/birth rates.
This will help us understand why murrelets in Central California
may be declining, and whether we have a viable population.
Analyses: In collaboration with Dr. Vicki Friesen and
Dr. Timothy Birt at Queen's University, I am collecting
blood samples from the birds we are catching in order to
conduct genetic analysis of murrelets in California. Genetic
markers can be used to estimate rates of movement of individuals
among breeding populations and will enable us to determine
if larger murrelet populations to the north are augmenting
the murrelet population to the south.