Blue Tit (Cyanistes caeruleus), perched on the lichen covered tree branches on Dartmoor. Lichen only grows in unpolluted environments, so this is an indication of how clean the air is up on the moors.
Blue Tit (Cyanistes caeruleus), perched on the lichen covered tree branches on Dartmoor. Lichen only grows in unpolluted environments, so this is an indication of how clean the air is up on the moors.