Arundel Wildfowl & Wetlands Centre. Superficially similar to Whooper Swan, but the marking on the bill is a bit more orange in Bewicks than the more yellow of Whoppers'. Also the extent to which that orange/yellow goes down the bill is diagnostic: it goes below the nostrils in Whoopers, above the nostril in Bewicks, as here. Whooper Swans are similar size to Mute Swans, Bewick's are smaller.

Bewick's Swan (Cygnus colombianus) (16/11/2008) Arundel Wildfowl & Wetlands Centre. Superficially similar to Whooper Swan, but the marking on the bill is a bit more orange in Bewicks than the more yellow of Whoppers'. Also the extent to which that orange/yellow goes down the bill is diagnostic: it goes below the nostrils in Whoopers, above the nostril in Bewicks, as here. Whooper Swans are similar size to Mute Swans, Bewick's are smaller.