RAS double century

The Retrapping
Adults for Survival (RAS) scheme was established in 1998 and uses bird
ringing to monitor survival rates of a range of bird species. Coverage is
particularly aimed at species which, due to their behaviour or the habitats
they occupy, are not often caught by standard mist netting activities in
woodland, wetland or scrub, such as Swallows, Dippers, Pied Flycatchers and
many seabirds