Trans-Pacific Migration of the Sooty Shearwater: 2004

A project of Pacific Procellariid Research Consortium in conjunction with the partners and sponsors detailed below.

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Introduction

The Sooty Shearwater (Puffinus griseus; Family Procellariidae) is a long-lived, wide-ranging pelagic seabird, that nests on sub-Antarctic islands off New Zealand, Tasmania, and Chile. After nesting, shearwaters disperse north to forage in the productive waters of the Peru Current, the California Current, and as far as the Gulf of Alaska. Off California, Sooty Shearwaters are the most abundant, and perhaps the most conspicuous seabird during May to September. Their affinity for productive coastal waters in the vicinity of upwelling centers leads to spatially predictable and extremely aggregated distributional patterns of single flocks numbering 10?100s of thousands of individuals and often extending for several kilometers in narrow bands just off the coastline (Briggs & Chu 1986).

In Phase I we are using satellite telemetry to (1) determine individual, regional residence durations during the annual molting period, and (2) collect fine-scale movement information that will help us determine critical at-sea habitats, and how movements may be influenced by upwelling events, variability in wind speed and direction, and diurnal and lunar cycles.

Preliminary results indicate that Monterey Bay and southern-central California are important destinations for these exceptional trans-pacific migratory seabirds during the austral (southern) winter. During May through September, shearwaters that have migrated here from breeding colonies in New Zealand and Chile spend considderable time (>2 months) in these waters feeding on abundant and predictable concentrations of prey (e.g. anchovy, sardine, rockfishes, squid, and krill) in order to rebuild energy reserves, undergo energetically expensive molt, and store lipids prior to re-migration across the Pacific.

Phase II of our research builds on our genetic analyses during 2003 that indicates shearwaters captured from flocks in northern Monterey Bay include individuals likely breeding in both Chile and New Zealand (C. Baduini pers. comm.). In September 2004, our team deployed 14 satellite transmitters in an attempt to capture the timing and transpacific migratory routes of individuals as they return to breeding colonies in the southern hemisphere.

Anticipated transmitter duration may allow us to gather information about movements and habitat associations during this species? pre-laying ?honeymoon?, when birds recover from migration and prepare for breeding by fattening up on abundant food associated with sub-Antarctic waters.

Project Partners

This ongoing study is a collaborative effort among scientists from Moss Landing Marine Laboratories (Josh Adams & Dr. James Harvey), Duke Marine Laboratory, (Dr. K. David Hyrenbach), and the Claremont University Consortium (Dr. Cheryl L. Baduini). Fieldwork would not have been possible without the dedicated support provided by numerous colleagues, and students and interns from Moss Landing Marine Labs.

Project Sponsors

This project was funded by the California Department of Fish and Game Oil Spill Response Trust Fund through the Oiled Wildlife Care Network at the Wildlife Health Center, School of Veterinary Medicine, University of California Davis. This research was approved by the SJSU Institutional Animal Care and Use Committee (#807), and conducted under CDFG Scientific Collecting Permit #6443.

** These are preliminary data. Please do not cite or distribute without permission from the authors.