In common with all wildlife today, the mute swan faces many environmental hazards, a major one being the dramatic loss of feeding, nesting and territorial sites. Now the numbers of swans are higher territorial disputes feature more. Many swans now do not breed until they are five or six years old so the competition for nesting sites is greater. The numbers of Canada geese on our lakes and rivers force the swans to compete for food. When swans are able to claim a territory and breed successfully the hazards the young cygnets face are rats, mink, foxes, magpies, crows and herons, not to mention pike.
Although the majority of lead weights have been banned some are still in use by unregulated fishermen. In addition unsupervised and untrained anglers can leave lines unattended causing inevitable problems. We are delighted to work with many reputable fishing clubs who give us their support and as many people will know leave the riverbank or lake cleaner after they leave than when they arrive.
General litter such as plastic bags, ring pulls and plastic from the top of cans also cause problems. As can water pollution, cooking oil from boats, paint, diesel or petrol spillage. Swans dislike being dirty and in their efforts to clean their plumage can ingest these pollutants.
Regrettably we regularly admit birds suffering the effects of deliberate vandalism. These include shooting by airguns, crossbow, and catapults. Deliberate beatings also occur. Unsupervised dogs can also cause problems particularly in the breeding season.
Botulism features in the summer months with unsuitable items being fed to the swans or just dumped in the river. DVE (Duck viral enteritis) is not normally a problem on open rivers but in comparatively enclosed areas can prove fatal as it is carried in the faeces of ducks. During the summer months blue green algae can affect rivers and lakes.
There are other notifiable diseases that can affect swans, ducks and geese and we have to be aware of the symptoms and possible outbreaks. To this end we liaise with DEFRA and the Environment agency.