Geese migrating over the Pacific Ocean select altitudes coinciding with offshore wind turbine blades
February 27, 2024
- Renewable energy facilities are a key part of mitigating climate change, but can pose threats to wild birds and bats, most often through collisions with infrastructure. Understanding collision risk and the factors affecting it can help minimize impacts on wild populations. For wind turbines, flight altitude is a major factor influencing collision risk, and altitude-selection analyses can evaluate when and why animals fly at certain altitudes under certain conditions.
- We used GPS tags to track Pacific Flyway geese (Pacific greater white-fronted goose, tule greater white-fronted goose and lesser snow goose) on transoceanic migrations between Alaska and the Pacific Coast of the contiguous United States, an area where offshore windfarm development is beginning. We evaluated how geographic and environmental covariates affected (1) whether birds were at rest on the water versus in flight (binomial model) and (2) altitude selection when in flight (similar to a step-selection framework). We then used a Monte Carlo simulation to predict the probability of flying at each altitude under various conditions, considering both the fly/rest decision and altitude selection.
- In both spring and fall, geese showed strong selection for altitudes within the expected rotor-swept zone (20–200 m asl), with 56% of locations expected to be within the rotor-swept zone under mean daylight conditions and 28% at night. This indicates a high possibility that migrating geese may be at risk of collision when passing through windfarms. Although there was some variation across subspecies, geese were most likely to be within the rotor-swept zone with little wind or light tailwinds, low clouds, little to no precipitation and moderate to cool air temperatures. Geese were unlikely to be in the rotor-swept zone at night, when most individuals were at rest on the water.
- Synthesis and applications. These results could be used to inform windfarm management, including decisions to shut down turbines when collision risk is high. The altitude-selection framework we demonstrate could facilitate further study of other bird species to develop a holistic view of how windfarms in this area could affect the migratory bird community as a whole.
Citation Information
| Publication Year | 2024 |
|---|---|
| Title | Geese migrating over the Pacific Ocean select altitudes coinciding with offshore wind turbine blades |
| DOI | 10.1111/1365-2664.14612 |
| Authors | Emily L. Weiser, Cory T. Overton, David C. Douglas, Michael L. Casazza, Paul L. Flint |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Journal of Applied Ecology |
| Index ID | 70251828 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Western Ecological Research Center; Alaska Science Center Ecosystems |
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Movement Data for Migrating Geese Over the Northeast Pacific Ocean, 2018-2021
This dataset consists of one table with a record (row) for each goose location and columns containing location information and covariates. The dataset was used in an analysis of altitude selection and flight propensity in an accompanying paper (Weiser et al. 2024) and is being provided here to allow replication of that analysis. Goose locations (latitude, longitude, and altitude) were collected wi
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Movement Data for Migrating Geese Over the Northeast Pacific Ocean, 2018-2021
This dataset consists of one table with a record (row) for each goose location and columns containing location information and covariates. The dataset was used in an analysis of altitude selection and flight propensity in an accompanying paper (Weiser et al. 2024) and is being provided here to allow replication of that analysis. Goose locations (latitude, longitude, and altitude) were collected wi
Michael Casazza
Research Wildlife Biologist
Research Wildlife Biologist
Email
Phone
Paul Flint, Ph.D. (Former Employee)
Research Wildlife Biologist
Research Wildlife Biologist