Year-round and Diel Patterns in Habitat Use of Seabirds off Oregon

Orben, R.; Porquez, J.; Suryan, R. (2025). Year-round and Diel Patterns in Habitat Use of Seabirds off Oregon (Report No. OCS Study BOEM 2025-009). Report by Oregon State University. Report for Bureau of Ocean Energy Management (BOEM).

@techreport{Orben-2025-2082810,
author = {Orben, R and Porquez, J and Suryan, R},
title = {Year-round and Diel Patterns in Habitat Use of Seabirds off Oregon},
institution = {Oregon State University},
year = {2025},
month = {feb},
number = {OCS Study BOEM 2025-009},
address = {Camarillo, CA, United States},
url = {https://espis.boem.gov/Final%20Reports/BOEM_2025-009.pdf},
keywords = {Wind Energy, Floating Offshore Wind, Collision, Birds},
}

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TY - RPRT
TI - Year-round and Diel Patterns in Habitat Use of Seabirds off Oregon
AU - Orben, R
AU - Porquez, J
AU - Suryan, R
AB - Oregon hosts approximately 1.2 million breeding seabirds and even more summer and winter migrants with at-sea residence times of days to months. Common Murres are the most abundant breeding bird, followed by storm-petrels, cormorants, and gulls. Over the course of this project, we filled critical seabird tracking needs of mid-sized species: Common Murres, Western Gull, Pink-footed Shearwaters, and Pacific Loons (Chapter 1). We then compiled available tracking data into the Oregon Seabird Tracking Inventory (a subset of the California Current Ecosystem Seabird Telemetry Atlas). We provide a Brownian bridge density framework for analysis and visualization that combines data from multiple location types (Argos, GPS) and summarize the data within the Oregon Exclusive Economic Zone and the northern California Current System (Chapter 2). An understanding of seabird flight heights is needed to estimate collision vulnerability to offshore wind energy development. While many challenges are inherent in using GPS altitude fixes for this purpose, we used bootstrapping methods to estimate the percentage of time spent within the Rotor-Sweep Zone for seabird species (Chapter 3). We then applied boosted regression trees (BRTs) to disentangle environmental, bird behavior, and electronic-based influences on seabird flight heights. While our BRT models only performed moderately well the results provide ecologically plausible insights into the factors that influence seabird flight heights. At-sea observations of seabirds can fill critical gaps in identifying which species are present in Oregon waters. Here we summarize at-sea survey efforts for three surveys (2015-2017) in the northern California Current System and compare the species composition and at sea densities to telemetry-derived utilization distributions (Chapter 4). This study highlights available seabird tracking data off Oregon and critical gaps in our spatial understanding of smaller-bodied seabird species including storm-petrels, Tufted Puffin, and Cassin’s Auklet.
CY - Camarillo, CA, United States
DA - 2025/02//
PY - 2025
SP - 82
PB - Oregon State University
SN - OCS Study BOEM 2025-009
UR - https://espis.boem.gov/Final%20Reports/BOEM_2025-009.pdf
LA - English
KW - Wind Energy
KW - Floating Offshore Wind
KW - Collision
KW - Birds
ER -

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Abstract

Oregon hosts approximately 1.2 million breeding seabirds and even more summer and winter migrants with at-sea residence times of days to months. Common Murres are the most abundant breeding bird, followed by storm-petrels, cormorants, and gulls. Over the course of this project, we filled critical seabird tracking needs of mid-sized species: Common Murres, Western Gull, Pink-footed Shearwaters, and Pacific Loons (Chapter 1). We then compiled available tracking data into the Oregon Seabird Tracking Inventory (a subset of the California Current Ecosystem Seabird Telemetry Atlas). We provide a Brownian bridge density framework for analysis and visualization that combines data from multiple location types (Argos, GPS) and summarize the data within the Oregon Exclusive Economic Zone and the northern California Current System (Chapter 2). An understanding of seabird flight heights is needed to estimate collision vulnerability to offshore wind energy development. While many challenges are inherent in using GPS altitude fixes for this purpose, we used bootstrapping methods to estimate the percentage of time spent within the Rotor-Sweep Zone for seabird species (Chapter 3). We then applied boosted regression trees (BRTs) to disentangle environmental, bird behavior, and electronic-based influences on seabird flight heights. While our BRT models only performed moderately well the results provide ecologically plausible insights into the factors that influence seabird flight heights. At-sea observations of seabirds can fill critical gaps in identifying which species are present in Oregon waters. Here we summarize at-sea survey efforts for three surveys (2015-2017) in the northern California Current System and compare the species composition and at sea densities to telemetry-derived utilization distributions (Chapter 4). This study highlights available seabird tracking data off Oregon and critical gaps in our spatial understanding of smaller-bodied seabird species including storm-petrels, Tufted Puffin, and Cassin’s Auklet.