The number (and percentage of species totals) of each of the two age classes of great tits in a marked population wintering in Wytham woods in 2011–2012.

Statistics are shown for individuals that visited devices at least once (Visited), and for those that had pecked at least one key (Pecked). Individuals not recorded on the regular grid of feeders (N = 1; see Methods for details) were not included in the analyses.