The family of swans, based at Kettle Brook Nature Reserve in Stonydelph, were taken to Linjoy Wildlife Sanctuary and Rescue in the early hours of Saturday morning with bite injuries after the adult swans were attacked.
The mother succumbed to her injuries yesterday and Lindsey Newell, from the Sanctuary, confirmed the male had also passed away this afternoon.
The eight cygnets were the swans second brood, having raised nine young cygnets during lockdown.
"Both of the parents had been attacked by a dog," Lindsey said.
"The dad had a bite wound to his leg and mum had bite wounds to the left wing resulting in multiple fractures of the wing. She also has wounds on her back.
"As the female was undergoing a moult, it meant she had no way of escaping from a dog as it renders them flightless until the feathers grow back.
"She sadly succumbed to her injuries and passed away., having been held by her wing and bitten on the back.
"As a result of the struggle, her wing broke in two places including the humerus which takes a lot of strain usually. Multiple bites on her wings and body, along with the fractures and the shock left her unable to fight anymore.
"It was such a waste of life of an animal just wanting to raise her young.
"Sadly, the male has also died of shock and maybe seeing her die. He stopped eating and had no interest in the cygnets. He paid no attention to them whatsover. He just seemed to have given up.
"We now have eight orphans to care for sadly.
"This situation was easily preventable. Dogs should be on leads around wildlife and livestock, especially if you can not recall your dog when there is a distraction.
"At this time of year, birds and mammals are also nesting and rearing young. Allowing a dog to run rampant puts wildlife at risk and leads to nests and babies being abandoned."
A spokesperson for the RSPCA said: “Terrible incidents like this could be avoided if dog owners ensure they are responsible and keep their pet on a lead around wildlife.
“We ask that dog owners be aware that there may be wild animals present in the area when walking their dog and to keep their dog under control at all times.
“Dog owners have a legal responsibility under the Dangerous Dogs Act 1991 to keep their dog under control in a public place.”
Donations to help towards the care and veterinary bills of the cygnets can be sent via paypal.com/donate/?hosted_button_id=LYJNQFKQDRGVN&fbclid=IwAR0-M7KSvMr9MUzi5Kwqy0YDbY-mvPnrM-ZM6V_GMZpuJtz3diQITv6WvP4