Abstract:

The moult of Savi's Warbler was studied in 9 consecutive years, between 1990-1998 at Ócsa Ringing Station (central Hungary). During this period a total of 139 Savi's Warbler (Locustella luscinioides) moult cards have been collected. According to the sequence and initiation point of the wing feather moult, the data were divided into three groups: (1) the descendent group: birds which showed a normal descendent sequence when caught; (2) the excentric group: birds that initiated the moult with a central primary and did not show an ascendant "wave"; (3) the divergent group initiated the moult from a central primary and showed both the ascendant and descendent waves. The excentric group was divided into subcategories by the initiation locus. We examined separately the extent and timing of the postnuptial moult in the (1) and (2) groups. The date of moult initiation and also the speed of moult increased with the decreasing number of primaries involved in moult. Possible explanations for individual variation of moult characteristics - second clutch, brood failure, time stress and alternative strategies - are discussed.