First adult SC: Moult initiated during 2cy spring (c. April-May, sometimes even before spring migration). The moult is usually arrested before or during autumn migration, with some retained outermost juv PP (at Ottenby often 2-4 retained), and often also a few juv SS and RR.
Subsequent adult SC: Moult initiated during spring (c. May-June), regularly with two centres in the PP. The moult is usually arrested before or during autumn migration.