Colour-ring resightings and flock counts link the increasing Welsh wintering Barnacle Goose Branta leucopsis flock to a naturalised breeding population in the Lake District

Abstract

ABSTRACT In the early 1990s, Barnacle Geese Branta leucopsis started wintering regularly on the Dyfi Estuary, Wales, increasing to 380 birds in 2012. To inform future site-management decisions, 25 birds were caught and fitted with colour rings in November 2013. Fourteen of these individuals were resighted the following spring at Derwent Water in the Lake District. Peak seasonal counts correlate strongly between the two sites, implying that at least the majority of the wintering birds on Dyfi are of naturalised origin.