Unusual pattern of skipped or shortened moulting of flight feathers in late-breeding Common Shelducks

Abstract Experimental studies have shown that individual wildfowl can shorten or skip moulting if the time between breeding and wintering is short; however, in wild birds are scarce. We tracked nine Common Shelducks Tadorna tadorna during seasons determined flightless based on typical movement patterns. found different patterns for two late-breeding females, suggesting they skipped shortened moult of their flight feathers. These results provide a link previous experimental situation birds, likely reflecting an trade-off times allocated to breeding, respectively.