Singing territories and home ranges of breeding Chaffinches: visual observation vs. radio-tracking

Abstract

We mapped the singing territories of individually marked Chaffinch malesin a36-ha study plot in southern Finland by visual observation in 1985-87. In addition, we followed the movements of five males with radio-tracking in 1987 . The habitat blocks comprising old spruce-dominated forests were almost completely occupied each year, whereas variation in pine-dominated forests was greater . Radio-tracking showed that the males spent a considerable amount of their time outside the singing territories . Home ranges were 4-8 times larger than singing territories and included a broad range of different habitat types. Home ranges also appeared to vary in size and habitat structure from male to male . Territorial males showed no aggressive behaviour towards non-singing males that moved in their singing territory. Our data suggest that "economic" models of bird territoriality are not realistic for the Chaffinch.