Any swan that is showing signs of sickness and/or debility that has been taken into care should receive proper veterinary attention as soon as possible. All but the minor injuries should be subject to veterinary treatment, and unless you can be certain that the slight injury obvious to the “lay” person is the only one.
When a swan is rescued with fishing line trailing from its mouth, and from down the throat, and resistance to the gentlest of pulls is felt, then the bird MUST be x-rayed to see if a hook or other tackle is lodged in the oesophagus. In this case, surgical intervention by a qualified veterinary surgeon is essential.
A swan that “crash lands” on a highway etc but shows no apparent signs of injury or distress should be taken into “quiet care” for 24 hours so as to rule out concussion or post traumatic shock.
For all more complex treatment regimes, follow instructions given by a qualified vet.
Swans are normally gregarious birds, and during time of stress exhibit a sense of reassurance and security when within “sight and sound” of their own kind. These birds should not be held in isolation and or in the facilities available at a mixed veterinary practice, but should be transported to a specialist unit as soon as practicable. (The Swan Sanctuary can advise and assist where necessary.)
It is often the case that both rescuers or members of the public , tend to assume any sickly swan is suffering from lead poisoning, to the experienced eye swans exhibit a wide range of symptoms which indicate a variety of illnesses and injuries.