The Whooper Swan has a yellow bill and no black knob like that of the Mute Swan. The yellow on its bill extends below its nostrilsAs we leave winter behind, the evocative, loud, bugling calls of Whooper Swans will soon fall silent for another year as these impressive winter visitors to Ireland depart northwards for their breeding grounds in remote areas of the Icelandic tundra. The other two have yellow bills, do not have black knobs on their foreheads, and are winter visitors from the far north. The Whooper Swan, the larger of the two winter visitors, is immortalised in the legend of the Children of Lir in which the children's wicked step-mother turned the four offspring of King Lir into swans. The Whooper Swan is larger and the yellow on its bill extends below its nostrils as shown above.

Source: Irish Independent March 05, 2021 18:22 UTC