Whooper Swans - Western Isles Bird Sightings
The whooper has a longer bill than that of the bewick swan with more yellow on the bill a long yellow wedge on side of the bill extends beyond the nostrils, whereas the Bewick swan has a rounded patch of yellow which falls short of the nostrils.
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Isle of Lewis , Harris and the Uists - Bird Sightings - Whooper Swans
The Mute Swan has orange on the bill, not yellow. The Bewick Swan has a more round head than that of the Whooper and mute. Whooper swans visit the Western Isles in the Winter.