The poor bird was spotted in Chelmsford, Essex, on Saturday 18 July, with locals saying he couldn't move.
RSPCA inspector Adam Jones, who was called to Argyll Road to help the young gull, said: "Staff at a car showroom nearby had spotted the gull around a week earlier and were concerned that he seemed to be struggling to walk. Whenever they got near him to see what was wrong he flew off.
"But on Saturday they became increasingly concerned because he'd been sat in the same spot for hours and didn't appear to be moving.
"I went out to catch him and when he tried to hop away he would stumble and fall. As soon as I caught him it was clear to see why as the poor thing had a disposable Covid face mask tangled around both legs."
Jones took the bird to the specialist team at South Essex Wildlife Hospital, where staff had to cut the mask off.
He continued: "It's clear the mask was there for some time and the elastic straps had tightened around his legs as his joints were swollen and sore.
"Thankfully, he's been doing well and is being monitored closely. They've now released him out into an aviary with other gulls and, when the group is ready, they'll all be released together.
"I'm concerned that this gull could be the first of many victims now that face masks are the norm."
Now the RSPCA is reminding people to take care with litter around wildlife, with the charity saying it has to help thousands of animals each year after they become injured or caught in anything from elastic bands and tin cans to plastic bags.
There is a new concern that face masks may pose an increasing issue as they become compulsory for many situations, and that people may discard them irresponsibly - meaning animals and birds could become tangled in the elastic straps.
Jones added: "I'd appeal to all members of the public to ensure they dispose of their face masks and disposable gloves - and all other types of litter - properly and responsibly, so that animals don't get hurt."
The RSPCA has also shared its top tips to protect wildlife from litter:
- Recycle and reuse as much as possible - and put everything else in the bin
- Cut the loop handles of plastic carrier bags before recycling to prevent animals being tangled
- Cut plastic can holders and elastic bands so animals can't get caught up
- Cut up balloons before putting them in the bin
- Cut up disposable gloves and snip the straps on face masks to prevent animals getting tangled
- Clean and empty containers after use and pinch cans shut or cut containers in half before recycling
For more information visit www.rspca.org.uk/adviceandwelfare/litter.Featured Image Credit: RSPCA