A method for population studies of butterflies at the landscape scale.

I here propose a modification of the English butterfly census method (Pollard 1977) for studies of large areas with a relatively low density of butterflies. The transect line should not be more than 10 m from any point in open terrain and open forests, but only 5 m from sunny edges and patches with a high density of flowers. The transect line is adjusted between visits to most intensively cover sites with the highest density of flowers. However,...