Recapture of Adults for Survival: Neath Port Talbot Dippers

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In autumn 2020 Colin Baker started a project on dipper covering the River Afan and its tributaries and the Nant Ffrwdwydd, Neath Port Talbot. This extended the existing Recapture of Adults for Survival (RAS) run by Wayne Morris and covering Rhondda Cynon Taf and Bridgend, into the Gower Recording Area, and forms part of the same project.

RAS projects set out to capture high quality data on survival rates that can be used to inform our understanding of population trends in species that are often not particularly well sampled by more standard methods (such as the Constant Effort Scheme). Extending the more established RAS on dipper that covers adjacent catchments to the east adds considerable value to the data set, as the combined study now covers a substantial proportion of Glamorgan.

The first stage of Colin’s work has involved establishing a baseline of territories by walking the water courses and checking features along them with the potential to supporting nesting birds. All accessible nests located are being monitored as part of the British Trust for Ornithology’s (BTO’s) Nest Record Scheme, for which dipper is a priority. Initial results suggest that the legacy of high water levels on the river in late winter may have been to slightly delay breeding, albeit young in some nests are now approaching fledging age. There also appear to be some vacant territories. 

Adult birds captured are being colour ringed, as this increases the potential for observations to be made in the field. An orange ring with a unique combination of letters and numbers is being used. Sightings of birds, including date and location, would be very welcome. The project is also collecting data for a PhD study looking at the dietary composition of dippers, so will provide information that will be used to understand both population trends and the ecology of the species. 

Colin wishes to thank GOS members Gwyn Randall, Dave Cornish and Phil Routliffe, as well as various members of Gower Ringing Group who have assisted with his work to date. Gwyn completed a breeding survey on the Afan in 2014 (included in Gower Birds Vol 10 No 3) that provided very useful context allowing the study to be extended.

Photographs, taken by Amy Schwartz, follow.

Any sightings of colour-ringed dippers in the area can be reported to Colin (dipper@ntlworld.com)

Gower Ringing Group

08/05/2021

 

A dipper captured as part of the study
A faecal sample for the PhD research
The supporting cast of species captured includes kingfisher
… and the equally attractive grey wagtail

 

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