Understanding demography is critical for understanding the causes underlying population declines, and for initiating and monitoring policies to reverse them. A method of fitting demographic models directly to avian count data recorded at a sample of census sites is described. The model is applied to national and regional counts of Common Starling Sturnus vulgaris in Britain for the period 1965–2000. Starlings have declined markedly during this time and are now on the list of birds of highest conservation concern. Although there have been small changes in various aspects of breeding success over this time, the analysis shows that these are unlikely to have made much impact on the long‐term status of the species. By incorporating estimates of survival, based upon recoveries of ringed birds, the model suggests that the pronounced national decline in Starling numbers since a period of stability in the 1970s is most likely to be due to changes in the survival of first‐year birds. This narrows the candidate range of environmental factors which might influence the decline and implicates changes in resource availability.
This is the 68th annual report of the British Trust for Ornithology's Ringing Scheme, covering work carried out, and data received, in 2004.During the year, changes in bird survival in relation to winter weather were studied. In almost all cases, there was a greater influence of weather on firstyear than adult survival.A paper providing guidelines to help those setting up demographic monitoring schemes for waders was produced, with ringing as a key component.Concern about a reduction in reporting rates of ringed birds led to a study of the changes. Declines were found across nearly all taxonomic groups and may reflect a combination of changes in reporting behaviour, ringing behaviour or bird behaviour.A study of the timing of muirburning used the ringing dates of pulli in conjunction with nest record data to assess its possible effect on breeding birds. There appears to be little reason for differences in cut-off dates for muirburning in different regions and at different altitudes, but further work is required to quantify more fully the effects on moorland birds.Data gathered as part of the Constant Effort Sites (CES) Scheme showed increases in the numbers of adults of several, mainly migrant, species, possibly as a result of high rainfall in Africa south of the Sahara. Productivity was good for most species. Cetti's Warbler Cettia cetti was added to the list of species covered and a study of habitat on CE sites showed that vegetation management mitigates the effect of habitat progression on catching rates.Data for 117 Retrapping Adults for Survival (RAS) studies were submitted.Over 12,000 Swallows Hirundo rustica were ringed as part of the Swallow Roost Project.The total number of birds ringed (881,920) was the highest ever, showing an 18% increase on the mean of the previous five years (1999)(2000)(2001)(2002)(2003). The recovery total (11,930) also increased (by 9% compared to the mean of the previous five years). Recoveries of 154 BTO-ringed birds and 102 ringed abroad are presented in the report. They include records that confirm suspected or known migration patterns as well as the more unexpected movements. This is the 68th annual report of the Ringing Scheme of the British Trust for Ornithology (BTO). It summarises the research carried out during 2004 using ringing data, along with the numbers of birds ringed and the reports of ringed birds (recoveries) received. The value of ringing as a scientific tool is clearly illustrated by the wide variety of conservation-related, pure and applied research for which it is used. The data are collected by over 2,000 volunteer ringers. The BTO runs the Ringing Scheme, fulfilling the duty of the UK and Irish governments (as members of the European Union) to support the study of migratory birds and maintain a ringing scheme. The BTO operates a permit system under licences from the statutory conservation agencies, which ensures ringers are trained to a high standard. The BTO also administers the statutory licensing of ringers and nest recorders to visit the nests of bir...
This is the 68th annual report of the British Trust for Ornithology's Ringing Scheme, covering work carried out, and data received, in 2004. During the year, changes in bird survival in relation to winter weather were studied. In almost all cases, there was a greater influence of weather on firstyear than adult survival. A paper providing guidelines to help those setting up demographic monitoring schemes for waders was produced, with ringing as a key component. Concern about a reduction in reporting rates of ringed birds led to a study of the changes. Declines were found across nearly all taxonomic groups and may reflect a combination of changes in reporting behaviour, ringing behaviour or bird behaviour. A study of the timing of muirburning used the ringing dates of pulli in conjunction with nest record data to assess its possible effect on breeding birds. There appears to be little reason for differences in cutoff dates for muirburning in different regions and at different altitudes, but further work is required to quantify more fully the effects on moorland birds. Data gathered as part of the Constant Effort Sites (CES) Scheme showed increases in the numbers of adults of several, mainly migrant, species, possibly as a result of high rainfall in Africa south of the Sahara. Productivity was good for most species. Cetti's Warbler Cettia cetti was added to the list of species covered and a study of habitat on CE sites showed that vegetation management mitigates the effect of habitat progression on catching rates. Data for 117 Retrapping Adults for Survival (RAS) studies were submitted. Over 12,000 Swallows Hirundo rustica were ringed as part of the Swallow Roost Project. The total number of birds ringed (881,920) was the highest ever, showing an 18% increase on the mean of the previous five years (1999-2003). The recovery total (11,930) also increased (by 9% compared to the mean of the previous five years). Recoveries of 154 BTO-ringed birds and 102 ringed abroad are presented in the report. They include records that confirm suspected or known migration patterns as well as the more unexpected movements.
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