Bird ringing in Britain and Ireland in 2001

Abstract

This is the 65th annual report of the British Trust for Ornithology's Ringing Scheme covering work carried out and data received in 2001. As part of the BTO's production of the landmark Migration Atlas: movements of the birds of Britain & Ireland, which will review movements of birds using Britain & Ireland, novel approaches to the investigation of the movement patterns and distances were developed. These allow the objective comparison of whether different species are sedentary, short‐distance or long‐distance migrants and the investigation of differential migration between birds of different age and sex. The BTO continues to carry out a programme of work investigating the declines in bird populations. In 2001, an investigation of Song Thrush population dynamics showed that the survival rates of young birds was key in the population decline; reduction in survival rates also seemed to have driven the fall in numbers of Marsh Tits. Work on movements of waders between roosts on the Moray Basin showed little movement for most species; important information when the possible effects of disturbance are being considered. An investigation of the biometrics of the Redshank wintering on Severn Estuary found that the proportions of Icelandic and British breeders varied between sites; again an important factor in assessing the possible consequences of disturbance. A pilot project, which is investigating the collection of data on movements and demography of farmland passerines in winter is described. Data collected as part of the Constant Effort Sites (CES) Scheme showed significant changes in the numbers of seven species between 2000 and 2001. Of these, five resident species (Blackbird, Blue Tit, Great Tit, Chaffinch and Greenfinch) and one migrant (Whitethroat) showed increases. Only one species (Willow Warbler) decreased. By contrast, productivity tended to be low with 11 species, both residents (Dunnock, Robin, Blackbird, Long‐tailed Tit, Blue Tit, Greenfinch and Reed Bunting) and migrants (Sedge Warbler, Reed Warbler, Blackcap and Chiffchaff) showing significant declines. Progress on the EURO‐CES project, which aims to develop standard protocols for CES fieldwork and data capture across Europe is reported. Data sets for 86 studies of 42 species were submitted as part of the Retrapping Adults for Survival (RAS) Project. The first detailed analysis of Pied Flycatcher data from RAS‐type studies showed that survival rates vary between different areas of the country and confirms the value of this project. The numbers of birds ringed in 2001 (648,936) was 16% below the mean of the previous five years (1996–2000), largely as a result of Foot and Mouth Disease, which restricted the areas ringers had access to. The recovery total (10,692) was 6% lower than the five‐year mean (1996–2000). Recoveries of 195 BTO‐ringed birds and 77 birds ringed abroad are presented in the report and include a number of unusual or significant movements. Of particular note are the first recovery of a Great White Egret involving Britain & Ireland, the first recoveries of BTO‐ringed Honey Buzzards, a BTO‐ringed American Golden Plover recovered in Italy, an Hungarian‐ringed Knot found in England and the first foreign‐ringed Yellow‐browed Warbler (from Norway) to be reported in Britain & Ireland.