Lesser Black-backed Gull 2CY, May 29 2017, Heemskerk, the Netherlands.
      Bird is not ringed, no provenance on origin. Intermedius x fuscus-type 2CY bird. 
       With advanced post-juvenile moult in late winter, prior to northbound migration. P1-P7 replaced, then arrested its moult. 
        
      
      
      
      
      
     
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