Movements and flock behaviour of Barnacle Geese on the Solway Firth

Abstract

Caerlaverock National Nature Reserve is described in relation to its importance to wintering Barnacle Geese. Barnacle Geese arrive in the Solway Firth, from the north or north-east, in late September or early October, though 40 days may elapse before the flock is at full strength. Immigration reaches its peak during the first 20 days of October. Northward migration may be more abrupt and occurs most often in late April. In winter quarters Barnacle Geese occupy three main types of habitat - saltmarsh, farmland and tidal sand. Factors which appear to limit feeding areas are discussed. Changing conditions in the Solway and the incidence of bright moonlight apparently affect Barnacle movement to some extent. Amongst recognisable causes of disturbance, the geese react most often to passing aircraft, moderately often to man, and least often to other birds and farm stock. Barnacle Geese spend most of their daylight hours in feeding, except when occupying tidal foreshore. Their observed activities, including flock segregation and characteristics of flight, are described and discussed.