Arundel Wildfowl and Wetlands Centre. Superficially similar to Bewick's Swan but Bewick's instead has a slightly more orange hue to its bill. Also the extent to which that orange/yellow goes down the bill is diagnostic: it goes below the nostrils in Whoopers as here, and above the nostril in Bewicks. Whoopers are about the same size as a Mute Swan, Bewick's smaller.

Whooper Swan (Cygnus cygnus) (20/08/2006) Arundel Wildfowl and Wetlands Centre. Superficially similar to Bewick's Swan but Bewick's instead has a slightly more orange hue to its bill. Also the extent to which that orange/yellow goes down the bill is diagnostic: it goes below the nostrils in Whoopers as here, and above the nostril in Bewicks. Whoopers are about the same size as a Mute Swan, Bewick's smaller.

Arundel Wildfowl and Wetlands Centre. Hardly any difference between males and females - males are a bit larger and have broader wingspans and longer necks. I have a feeling the one on the left is a Cob (male) and the one on the right a Pen (female).

Whooper Swans (Cygnus cygnus) (16/10/2006) Arundel Wildfowl and Wetlands Centre. Hardly any difference between males and females - males are a bit larger and have broader wingspans and longer necks. I have a feeling the one on the left is a Cob (male) and the one on the right a Pen (female).

Whooper Swans (Cygnus cygnus) (16/10/2006) Arundel Wildfowl and Wetlands Centre. I reckon this is a male as it is the same one from the previous image.

Whooper Swans (Cygnus cygnus) (16/10/2006) Arundel Wildfowl and Wetlands Centre.

Whooper Swan (Cygnus cygnus) (20/08/2006) Arundel Wildfowl and Wetlands Centre.