Marbled Murrelet Project
“An Evaluation of Human-Caused Disturbance on the Breeding Success
of Marbled Murrelets in Redwood National and State Parks.”
 Summary:
The Marbled Murrelet (Brachyramphus marmoratus) is a secretive and solitary
monomorphic seabird. The species was listed as endangered in California
in 1992. Later the Washington, Oregon, and California Marbled Murrelet
populations all received federal listing as threatened under the U.S.
Endangered Species Act. Greater knowledge of the behavioral responses
of murrelets on nests, to various forms of human disturbance or related
predator actions, will allow for an evaluation of possible management
actions designed to reduce certain types of human disturbance during the
breeding season (while still allowing for other park activities to occur
without impacts to murrelets), and a better understanding of the impact
of predators on murrelet  nest
success. The purpose of our study is to locate and intensively survey
Marbled Murrelet nests, over a period of 3-5 years, to determine the effects
of human disturbance on Marbled Murrelet breeding success. Other factors
affecting breeding success (e.g., predation, at-sea foraging areas) will
also be examined. The information gathered during this study will allow
a critical evaluation of the Marbled Murrelet Recovery Plan recommendations
regarding the effects of human disturbance on murrelet nesting success.
Also, data gathered during this study will also further our understanding
of the reproductive ecology, and habitat requirements of breeding and
non-breeding Marbled Murrelets in northern California. The objectives
of the research are the following:
1) To locate Marbled Murrelet nests in Redwood National and State Parks.
Subsequent to locating nests we will describe nest habitat, and measure
reproductive success of these nests.
2) To measure behavioral responses of Marbled Murrelet adults and chicks
to disturbance produced by trail users.
3) To measure behavioral responses of Marbled Murrelet adults and
chicks at the nest to disturbances produced by maintenance acitivities
(chainsaws).
4) To determine flight corridors and habitat choice by prosepecting
Marbled Murrelets. Subsequent to locating prospecting sites we will
describe the biological and physical habitat.
The ancillary objective is: To describe at-sea locations,
and movements of radio-tagged birds relative to the availability of nesting
habitat.
Funding Agency: USGS, National Park Service, California
State Parks and Recreation, U.S. Bureau of Reclamation, California Department
of Fish and Game, Bureau of Land Management.
Collaborators: USGC Dixon Field Studies,
Western Ecological Resource Center
Graduate Student: Brian Acord
Beginning Date: Jan 2001
Reports: R.T. Golightly, P.N. HJbert, and D.L. Orthmeyer.
2002. Evaluation of human-caused disturbance on the breeding success of
Marbled Murrelets (Brachyramphus marmoratus) in Redwood National and State
Parks, California. Unpubl. Progress Report, Humboldt State University,
Department of Wildlife, Arcata, CA., and U.S. Geological Survey, Western
Ecological Research Center.
Golightly, R.T., P.N. Hebert, H.R. Carter, and D.O. Orthmeyer. 2003. Radio-telemetry evidence of re-nesting in the same season by the Marbled Murrelet. Colonial Waterbirds 26:261-265.
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