flock of white-winged black tern birds on wetlands during a spring nesting period

poland biebrzanski biebrza park national reserve color colorful travel tourism outdoor nature bird birdie animal avian wing wings living wildlife wild green wetland wetlands moor marsh marshes swamp swamps natural conservation bill beak tail flying fly portrait leaf bush whitewinged black tern chlidonias leucopterus rybitwa bialoskrzydla many flock group pack