The CES Scheme uses standardised bird ringing to monitor the abundance, breeding success and survival of 24 common breeding songbirds. Over 120 sites across the UK are monitored by qualified volunteer bird ringers through the breeding season, with twelve standard visits between May and August. 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.
Many CES ringers submit their data by the end of October. This data is used to create the preliminary results for adult abundance and productivity which give a good indication of the trends for the season. This is published in November on these CES web pages. The most recently published results are those for 2013. Preliminary results for previous years are also available.
All data are submitted by end February and used to create the final results which include adult survival. These results are published in CES News in the spring which is sent to all CES ringers with a here. The most recently published results are those for 2012. Results for previous years are available through previous newsletters.
Results of CES are combined with the results of other BTO surveys: Nest Record Scheme, Breeding Bird Survey, Waterways Breeding Bird Survey, Wetland 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 are those for 2011.
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 2011 published in the December 2012 edition.