CES Results

The CES Scheme uses standardised bird ringing to monitor the abundance, breeding success and survival of 24 common breeding songbirds. Approximately 120 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.

Fieldwork for CES occurs from early May to early September. Results are then included in the following outputs:

Preliminary Trends

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

Final results

All data are submitted by the end of Janaury and are used to create the final results which include adult survival. These results are published in the spring edition of LifeCycle, the BTO magazine for ringers and nest recorders. Results for previous years are available through previous editions of LifeCycle or CES News.

Annual stats

View a breakdown of the results from previous years. Overall totals are given and results are also broken down by CES habitat and by country. Results shown include the number of sites, the number of birds and species caught, the top 15 species caught as well as averages per site.


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. View the most recently published BirdTrends report.


Ringing Report

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.

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