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Resources for Volunteer Seabirds At Sea, and European Seabirds At Sea surveyors

These resources are for those taking part in JNCC’s Volunteer Seabirds at Sea (VSAS) survey programme but would also be useful to anyone using ESAS or any other distance sampling method to conduct bird or cetacean surveys. The resources on this page are supplementary to JNCC's VSAS training program.

VSAS survey methods manual

This document outlines the survey methods for a VSAS or ESAS survey, gives guidance on best practice and data recording, and instructions on using JNCC's bespoke VSAS data entry app. The manual can be found at the link below.

VSAS manual


Rangefinder formula

Each observer taking part in a VSAS or ESAS survey will need to make a rangefinder, unique to themselves and that specific observation platform. You will need to know your eye height (i.e. your height + the height of the observation platform) and your arm length (from eye to fingertips). These details are used to build the rangefinder that allows observers to delineate distance bands for birds on the water.

Rangefinder formula



Monitoring Seabirds At Sea

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