The horrifying images show the scale of littering and its impact on wildlife. Photographs taken at Drumpellier Country Park, near Coatbridge, North Lanarkshire, showed two eggs laid in a nest while the surrounding area was littered with detritus.
Empty drinks cans and bottles were scattered around, despite litter bins nearby. One visitor said: "It is absolutely disgusting.
"The poor swans. It is so embarrassing that we have this beautiful park in Coatbridge and the privilege of having these lovely animals yet look how poorly we are taking care of both.
"My daughter lives near Queen's Park in Glasgow and there's a pair of nesting swans there. 'The nest is pristine and nothing like this mess we can see here. 'It's unacceptable.'"
Scottish SPCA chief superintendent Mike Flynn told The Metro: 'Sadly, we have noticed an alarming increase in animal injuries due to incorrectly discarded rubbish, with everything from cats and bats, to badgers and foxes being affected.
"We want to remind everyone that they can help save wildlife by properly disposing of their rubbish."
A spokesman for North Lanarkshire Council said: 'Discarded rubbish is a blight not only for park users, but also poses a risk to the animals that call the park home.
"We would urge everyone using the park to properly dispose of any litter in the bins provided. 'Anyone caught throwing rubbish away will face being fined."