alba animal animals arenaria autumn belgian belgium bird birds breakwater britain british calidris coast coastal december europe european fauna flock flood flooding france french German germany great groin group groups groyne high interpres Kingdom maritima migratory nature netherlands non-breeding north of passage plumage poles purple refuge rest resting rising ruddy sanderling sanderlings sandpiper sandpipers scolopacidae sea shore shorebirds shores tide turnstone turnstones uk United wader waders wading water wildlife winter wintertime wood wooden zeeland