Blue Tit - Parus caeruleus
Familiar garden resident in most of mainland Britain and Ireland, often coming to bird feeders in winter months; a common woodland species as well. Has elements of blue, green and yellow in its plumage with striking dark markings on head; juvenile similar to adult but lacking blue in plumage. Utters familiar, chattering tserr err err err call and has whistling song. Nests in tree holes and readily takes to hole-fronted nestboxes. In summer, feeds mainly on insects.