Bird ringing in Britain and Ireland in 2005

Abstract

This is the 69th annual report of the British Trust for Ornithology's Ringing Scheme, covering work carried out, and data received, in 2005. Important research on Oystercatchers Haematopus ostralegus in North Wales showed that survival of adults, recruitment of juveniles and mass of both adults and juveniles were lower during winters when there was mechanised dredging for shellfish. A study of weight changes of House Sparrows Passer domesticus in autumn and winter found that they spread their weight gain through the day, thus potentially decreasing their risk of predation, but increasing their risk of starvation. Data gathered as part of the Constant Effort Sites (CES) Scheme showed an annual increase in adult numbers for five species (one migrant and four residents) and an annual decrease for five species (four migrants and one resident). Productivity was variable with 11 species having above‐average productivity and 13 below‐average. Work began to develop methods to produce annual survival trends by integrating CES data from the 350 sites that have taken part in CES over the last 21 years. Data for 110 Retrapping Adults for Survival (RAS) studies were submitted. Over 13,000 Swallows were ringed as part of the Swallow Roost Project, which ran until 2006. The total number of birds ringed (873,581) was exceeded only in 2004 and was a 12% increase on the mean of the previous five years (2000–04). The recovery total (12,658) was the second highest in the last decade, being exceeded only in 2004, and was 9% higher than the mean of the previous five years. A total of 236 selected recoveries are presented in the report. They include unexpected movements and others that confirm suspected or known migration patterns.