Keywords: K3HATTYUDANKAKKAL.jpg en Mute Swan Cygnus olor and some Black-headed Gull Chroicocephalus ridibundus on the ice hu Bütykös hattyú Cygnus olor és néhány Dankasirály Chroicocephalus ridibundus a jegen Kew Gardens Dénes Emőke 2010 december 21 Cc-zero Cygnus olor swimming in mixed species flocks Chroicocephalus ridibundus with other species |