The periodic shedding of the feathers; also applied to indicate the period during which moulting occurs. Usually three different important moults can be recognised: adult pre-breeding (giving the bird its special plumage for the mating and breeding season), adult post-breeding (giving the bird its 'normal' appearance back after breeding) and post-juvenile (giving the bird its full adult appearance). The main moult of the annual cycle is almost invariable the 'post-breeding' moult; this is usually complete, involving not only the body plumage, but also the flight- and tail-feathers. The 'pre-breeding' moult is normally partial (giving only some temporally special features to the plumage) and the 'post-juvenile' moult is very variable in timing and extent but always the first moult in which contour feathers are replaced.

Alternative forms for moult : moulted, moulting.