A structure made of stone, bricks and concrete, once used as a hut for spotting and hunting birds. Bird snares, often built on slopes or in raised positions, became widespread in Lombardy, Veneto and Tuscany from the 18th century onwards. The structure of the bird snare consisted of: the casello (a wooden or masonry tower), the tondo (a small meadow in front of the tower) and the colonnade (a pergola formed by trees, mainly hornbeams, specially pruned). Nowadays the bird snares are used for scientific purposes: to study the migratory routes of birds by capturing, ringing and releasing them.