The wound looks like a turtle or similar bite. The cygnet needs to be immediately taken to an experienced avian veterinarian for examination and treatment. The cygnet will probably need surgery to clean the wound. The young bird will definitely need a series of antibiotic treatments.
This treatment will take approximately 2-3 weeks as the cygnet’s blood will need to be tested to ensure that the correct antibiotic is being used and the infection is completely gone. This time period will make it impossible to return the cygnet to its parents. If cygnets are not returned within 2-8 hours, ( we have seen a family of cygnets returned after 24 hours accepted, but very rare), the parents will abandon the cygnets or may seriously injure them. Therefore, if the cygnet survives treatment, you will need to find the cygnet a safe new home such as a waterfowl or wildlife sanctuary. The young bird can never be returned to the wild. The Regal Swan