Retrapping Adults for Survival (RAS)
The Retrap Adults for Survival (RAS) scheme is a national standardised ringing programme within the BTO Ringing Scheme that has been running since 1999. Ringers aim to catch or re-sight at least 50 adult birds of a single species in a study area during the breeding season. The study area is well defined and the ringer is aiming to record the vast majority of the adults.
In 2011 there were 158 projects throughout Britain and Ireland on species as diverse as House Sparrow, Moorhen, Pied Flycatcher and Manx Shearwater. The most recent RAS News provides a full list of the species.
RAS is used to give adult survival rates and is particularly useful for those species not widely covered by CES.
The Partners
The Retrappping Adults for Survival Scheme is supported by a partnership between the British Trust for Ornithology (BTO ) and the Joint Nature Conservation Committee (JNCC) (on behalf of: Council for Nature Conservation and the Countryside, Natural Resources Wales, Natural England and Scottish Natural Heritage). It is also part of the BTO Ringing Scheme which is funded by the BTO /JNCC Partnership, The National Parks and Wildlife Service (Ireland) and the ringers themselves.
Latest News from RAS
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RAS News 2013 Now Available
2012 RAS results are now available in the 2013 RAS News. Also included are articles on a number of RAS projects and information on how the analysis of RAS seabird data is developing.
Download a copy here.
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RAS News Spring 2012 published
Published in May 2012 it contains the RAS results from 2011. Also included are articles on RAS target species, colour-ringing for RAS, studies that are using RAS data and how historic data is being collected.
Download a copy here.
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Scientific papers published using RAS data
About the seasonal survival of suburban blackbirds
Summary: Survival is a key demographic parameter in bird populations yet remarkably little is known about the seasonal pattern of survival. Mortality may increase as a result of breeding behaviour, harsh environmental conditions, resource limitation or any combination of these; knowing which is important for understanding the ecology of population change. We analyse an intensive ten-year colour marking programme of European blackbirds Turdus merula to estimate seasonal and sex-specific survival rates. The annual survival rate (0.67) was similar to that produced from analyses of dead recoveries across Britain, but within year variation was significant. Survival rates were lowest during the early part of the breeding period and highest in the autumn, but there was little difference between the sexes. Understanding this pattern of variation is important in interpreting both life-history variation and the mechanisms of population change.
Robinson, R.A., Kew, J.J. & Kew, A.J. 2010. Survival of suburban blackbirds Turdus merula varies seasonally but not by sex. Journal of Avian Biology41:83–87.
How African rain affects the survival of Swallow, House Martin and Sand Martin
The BTO’s Retrapping Adults for Survival scheme is designed to monitor survival rates of species of conservation concern that are monitored relatively poorly by other forms of ringing. Here we present temporal trends in survival rates for three hirundine species, Barn Swallow Hirundo rustica, House Martin Delichon urbicum and Sand Martin Riparia riparia. Estimates of apparent survival rate were similar to those found in previous studies and were correlated with rainfall on the African wintering grounds, but not with
rainfall in Britain, suggesting that overwinter food resources may be more limiting.
rainfall in Britain, suggesting that overwinter food resources may be more limiting.
Robinson, R.A., Balmer, D.E. & Marchant, J.H. 2008. Survival rates of hirundines in relation to British and African rainfall. Ringing & Migration24:1–6
