The blue tit is an acrobatic and inquisitive bird; these traits have enabled it to exploit unusual food sources, for example by obtaining milk by pecking at milk-bottle tops on doorsteps. Furthermore, they are usually the first birds to find and use feeders put out in gardens, a trait which has greatly endeared them to the public (3). During summer they feed mainly on invertebrates, but switch to seeds and other food sources during winter when insects are scarce (3). Nesting takes place in holes in walls and trees, as well as in nest boxes (4). The female lines the hole or nest box with moss, hair and feathers, and in early May lays 7-12 (up to 16) white eggs speckled with reddish-brown (4). The male brings food to the female while she carries out the duty of incubation, which can take between 12 and 16 days (4). Both parents bring food to the young, which fledge after 15-23 days (4). Just one brood is produced each year (4).