CES RESEARCH - Introduction

The Constant Effort Site (CES) - Project is a bird ringing project in which birds are caught and ringed by means of a mist net. The research period coincides with the breeding season from mid April to the onset of August.

A number of restrictions of the CES project apply, birds are caught once in 12 blocks of 10days and from half an hour before sunrise until 6 hours later afterwards, no sound should be made to attract birds.
By means of the standardised method of the bird project, data are being obtained on survival (recapture of earlier ringed birds), reproduction (percentage first year birds) and monitoring (number of adult birds). The data collected is additional information supplementing several SOVON projects such as the nest card project and BMP-project.

At over 40 sites in The Netherlands, ringing occurs using this standardised method.

For more information about CES projects, please see the website from the BTO see CES.