'Mystery' illness kills Radipole Lake swans
29 October 2013 Last updated at 21:20 GMT
About 16 mute swans have died of a "mystery" illness at a wetland reserve in Dorset, the RSPB has said.
The charity said "half the herd" at Radipole Lake in Weymouth had been affected since September.
Two sick swans are being treated at West Hatch Animal Centre in Somerset. No other bird species has been affected.
The Animal Health and Veterinary Laboratories Agency is investigating the illness.