Hopefully, it will have flown off by tomorrow morning or at least not been attacked by a predator. The National Audubon Society promotes the killing of Mute Swans, those with orange beaks, so this may not be your best resource. If you can wrap it in a blanket, wrapping the wings so that the bird cannot strike you, then you can place it in a garage, shed, basement, barn, bathroom, etc. free from predators and harmful fumes so that you can have a chance to call a veterinarian or wildlife facility for help. Again, you will have to be careful who you call because even state wildlife entities are promoting the killing of these swans based upon junk science and misrepresentation. The birds Are Not an invasive species in spite of what has been stated. National Audubon Society and other wildlife entities (federal and state) want them killed to free up wetland habitats to promote introduction of the larger Trumpeter Swans for Trophy Waterfowl hunting purposes or other hunting waterfowl such as ducks and geese. Hopefully, the swan is just resting on its migratory path and will fly away. If not, hopefully, you will be able to affect a rescue. The Regal Swan