FLIGHT FEATHER MOLT IN THE RED-NECKED NIGHTJAR CAPRIMULGUS-RUFICOLLIS

The flight feather moult of the Red-necked Nightjar was studied in museum skins and in a free-living Spanish population during two summers. First winter birds start a complete moult of the remiges in their winter quarters following the typical moult sequence of other nightjars; however, as a rule it is interrupted before completion. Tail feathers are moulted partially. The following summer, birds reactivate the remex moult from the point it was stopped during the previous winter, but it is not finished until they reach the winter quarters; there, adults moult completely replacing descendantly first the outermost unmoulted primaries, and then the inner ones before moult is suspended again until the next post-nuptial moult, when the moult cycle is repeated. Thus, the moult of the Red-necked Nightjar is a cyclic process of periodically suspended moult stages, that is actively initiated already during the first winter moult and maintained during adulthood. I conclude that this moult strategy is related to the short time available for moult between breeding and autumn migration and the steep decline in food resources during the W African dry season.