The UK’s Chaffinch populations are boosted over winter by Scandinavian migrants. Winter Chaffinches exhibit ‘differential migration’. Females are more likely to travel further west and south west, hence we have more Chaffinches in the garden than in summer, and most are female. Males are dominant in winter, and females dominant during the breeding season, when the male accompanies them everywhere.
It is thought that females are pushed further afield in competition for scarce food in winter. In the South and East, the majority is likely to be male, hence their nickname ‘bachelor bird’ (males’ caps are grey in winter- the blue only emerges as the grey tips wear off in spring). Conditions: Heavy, continuous rain, but lacking the strong winds experienced in the South of England. Temperature: Max 6- Min 6c.