A pelican with a knife through its breast has evaded capture on WA's south coast, despite efforts by wildlife authorities and members of the public.

Busselton visitor Stephanie Downey spotted the pelican, which has been stabbed through its lower neck with a large knife, by the Denmark River mouth on Sunday and tried to approach it.

"Initially it was a few minutes of shock to see that large of a knife in the bird's chest and him still walking with it, so I initially wanted to help him," Ms Downey said.

"I got close enough to the pelican's tail where you can kind of rub him, but I didn't get close enough to the chest part, which to be honest was kind of better because I'd say if I actually did try to pull it out, [due to] the size of it I would have just done more damage to the pelican than good."

Instead, Ms Downey took a video of the pelican to draw professional attention to the bird's plight.

'One tough bird'

WA Seabird Rescue Albany coordinator Carol Biddulph, who is assisting the Department of Biodiversity, Conservation and Attractions with the rescue, was first alerted to the incident five days ago.

Ms Biddulph said while the pelican's knife injury was distressing, it did not appear to have damaged major organs.

"They've got a lot of padding around the front of the chest there, they have a lot of air sacs like bubble wrap," Ms Biddulph said.

Despite the knife injury, the pelican is still able to eat, fly and swim, and Ms Biddulph said it has a strong chance of survival if it receives help.

"It's one tough bird," Ms Biddulph said.

WA Seabird Rescue is urging the public not to approach or feed injured birds, as it makes them more averse to capture. ( ABC Great Southern: Mark Bennett )

"[I'm] certainly horrified that somebody could do such an act, but I've been dealing with wildlife for nearly 20 years now and there's some very strange people out there that like to do very nasty things to wildlife unfortunately."

Public's rescue attempts unhelpful

Ms Biddulph said the public's attempts to try capture the pelican were actually counterproductive, as they make it harder for experts to rescue it.

"Even when you've seen it it's going to be a tricky job, because so many good meaning members of the public … have been trying to catch it, so it makes the bird so wary," Ms Biddulph said.

It is not the first time volunteers have encountered such difficulties.

The Albany branch of WA Seabird Rescue is still trying to capture a silver gull with a kebab skewer in its neck and two pelicans punctured by fishing hooks that were first spotted in December.

Ms Biddulph urged the public not to approach or feed injured birds, but instead to call WA Seabird Rescue, the Department or a vet.