ORJIP: Improving methods for apportioning seabirds seen at sea both in the breeding season and non-breeding season (AppSAS)

Estimating the origin of seabirds seen-at-sea is an essential element of offshore wind consenting. The AppSAS project created a new tool for apportioning auk-protected species in the non-breeding season and expanded on existing methods to apportion black-backed gulls in the breeding season.

Front cover of AppSaS report


After an extensive review of five apportioning methods, the Apportioning seabirds seen-at-sea (AppSas) project created a new tool, Apportioning in the Non-Breeding Season (ANBS), to apportion guillemots and razorbills in the non-breeding season. 

The ANBS tool provides spatial distributions and apportioning estimates, using geolocation (GLS) from nine sites in the UK tracked between 2017 and 2021. For distant colonies, BDMPS estimates are provided.

Crucially, the tool quantifies uncertainty providing confidence intervals and the outputs can be used as inputs for the Scottish Government Cumulative Effects Framework.

ANBS tool

In addition, the AppSAS project has expanded the Scottish Government Cumulative Effects Framework to include GPS data for lesser black-backed gull on the breeding season.

This method derives colony-specific spatial distributions using data collected from 207 deployments in six sites between 2010 and 2020. This approach avoids the need to use more simplistic distance-decay approaches.
The tool will be published in the upcoming months.

The Offshore Renewables JIP (ORJIP) seeks to reduce the consenting and environmental risk of existing and future offshore wind farms through research. In the absence of empirical data, the offshore wind industry proactively follows a very conservative approach when estimating potential impacts on seabirds. The role of ORJIP is to review, update, and create empirical data to accurately estimate the environmental impacts of offshore wind, avoiding unnecessary conservativism. 

Resource Download Form

Download your copy

Complete the form below to access this resource (the download will appear at the bottom of this page).

Country *