A photographer has captured images of a peregrine falcon with its talons caught in a discarded face mask.
Steve Shipley, from Driffield, spotted the juvenile falcon on the Yorkshire coast.
He said it was very sad to see it struggling because someone had failed to dispose of a mask properly.
Mr Shipley is urging people to take more care and consider the risks posed to wildlife.
"It is a matter of people being a bit more responsible and disposing of the masks properly," he said.
"They are there to protect us, and the least we can do is not put anything else in danger."
The photographer encountered the bird on Sunday and said it eventually managed to free itself.
However, the mask would have prevented the bird being able to hunt and feed itself, and could have resulted in death, Mr Shipley said.
"There are only about a 1,000 breeding pairs in this country, and to lose one in this way would be a big loss," he added.
An RSPB spokesperson said: "This is incredibly disappointing to see.
"We all have the responsibility to clear up after ourselves and we should make sure that we dispose of facemasks and all other types of litter, properly and responsibly.
"By not doing so it's a danger not only to people but as we see in this case our wildlife too."
Earlier this week, a gull was rescued in Chelmsford, Essex, after getting its legs trapped in the elastic of a disposable face mask.
The RSPCA said it feared there could be a rise in similar cases as a result of the introduction of new face covering rules in England and Wales.