Bird ringing in Britain and Ireland in 2006

Abstract

This is the 70th annual report of the British Trust for Ornithology's Ringing Scheme, covering work carried out, and data received, in 2006. During the year recoveries of ringed birds were used to assess the possibility of highly pathogenic Avian Influenza H5N1being spread across Europe and into Britain by wild birds. Recovery reports were vital in understanding this risk and advising government. A study of wader survival using existing data showed that monitoring is possible, but is less effective in sites where there are low encounter rates. Constant Effort Site (CES) data show how widely adult numbers can vary from year to year, with six species showing a significant reversal in trend (with five having fallen) from the previous year. There is particular concern for Bullfinch as adult numbers decreased by 16% in 2006, a continuing downward trend that has seen numbers of the species halve since the 1970s. Five species showed a significant increase in productivity when compared to the previous year, while four showed a significant decrease. Data for 106 Retrapping Adults for Survival (RAS) studies were submitted. The final year of fieldwork for the Swallow Roost Project was completed. Although the total number of birds ringed (853,681) was lower than that in both 2005 and 2004, it was a 1% increase on the mean of the years 2002–05. The recovery total (13,785) was the highest since 1991, and was 16% higher than the mean of the previous five years. Recoveries of 251 individual birds are presented in the report. They include unexpected movements, movements that confirm suspected or known migration patterns, and longevity records.