CES Results

The CES Scheme uses standardised bird ringing to monitor the abundance, breeding success and survival of 24 common breeding songbirds. Over 140 sites across the UK are monitored by qualified volunteer bird ringers through the breeding season, with twelve standard visits between May and early September. Changes in the total number of adults caught provides a measure of changing population size, whilst the ratio of juvenile to adult captures provides an index of breeding success. Recaptures of adult birds ringed in previous years are also used to estimate annual survival rates.

The Results Timetable


Fieldwork for CES occurs from early May to early September.  

Preliminary Trends

Robin sitting on a wall singing

CES data submitted by 31 October are used along with NRS data to produce a preliminary report on breeding performance and adult abundance for the latest breeding season. The latest report is available here. Previous years' reports are available via the menu on the left.

Final results

Life Cycle cover spring 2016

All data are submitted by the end of February and used to create the final results which include adult survival. These results are published in the spring edition of Life Cycle, the BTO magazine for ringers and nest recorders.  The most recently published results are those for 2015 (PDF, 1.55 MB)  Results for previous years are available through previous editions of Life Cycle or CES News.

Bird Trends

BirdTrends image 

Results of CES are combined with the results of other BTO surveys: Nest Record Scheme, Breeding Bird Survey, Waterways Breeding Bird SurveyWetland Bird Survey, Heronries Census, Retrapping Adults for Survival and the general Ringing Scheme to give the Bird Trends report. This is used by conservation practitioners as a ready reference to changes in status among breeding birds in the UK. This is published in the autumn of the following year. The most recently published results can be found by clicking here.


Ringing Report

Image of the December 2015 cover of Ringing & Migration

CES is a key part of the Ringing Scheme. The Ringing Report is published in Ringing & Migration  and sets CES in the context of other ringing activity. It is published in the December edition of the following year. The most recently published results are those for 2014 published in the December 2015 edition.