Collision and Displacement Vulnerability among Marine Birds of the California Current System associated with Offshore Wind Energy Infrastructure

Capitalizing on open areas with persistent winds, offshore wind-energy infrastructure (OWEI) has the potential to produce a significant proportion of the power necessary to reach the United States’ alternative energy needs.... [ view full abstract ]

Capitalizing on open areas with persistent winds, offshore wind-energy infrastructure (OWEI) has the potential to produce a significant proportion of the power necessary to reach the United States’ alternative energy needs. Marine birds are vulnerable to collision with and displacement by OWEI. We created a comprehensive database of marine bird vulnerability to OWEI development in the California Current System (CCS). Using published values on population size, demography, life history, flight heights, and avoidance behavior for the 62 seabird and 19 marine water bird species that occur in the CCS; we generated three vulnerability values: Population Vulnerability, Collision Vulnerability, and Displacement Vulnerability. Population Vulnerability was used as a scaling factor to Collision and Displacement Vulnerability to generate two comprehensive indices: Population Collision Vulnerability (PCV) and Population Displacement Vulnerability (PDV). Pelicans, terns, gulls, cormorants, and Ashy Storm-Petrel had the greatest PCV scores. Brown Pelican (Pelicanus occidentalis) had the greatest overall PCV score. Alcids, terns, loons, and Ashy Storm-Petrel had the greatest PDV scores. Ashy Storm-Petrel (Oceanodroma homochroa) had the greatest overall PDV score. Using at-sea survey data, we also mapped bird densities within the CCS as a function of their cumulative PCV and PDV scores. This spatial analysis indicated areas in the CCS where seabirds would be more vulnerable to collision with and displacement by OWEI development. The vulnerability assessment presented here can be applied to specific locations in the CCS where OWEI is being considered and can be used to help inform decisions that will impact seabird conservation.