He is the elusive otter that has delighted wildlife-lovers across the city with his rare appearances.

But for most of us, Oscar the Norwich otter has proved near impossible to catch sight of as he goes about his river-dwelling business.

So just what do you have to do to spot the Wensum's most evasive apex predator?

Wildlife rescuer and otter enthusiast Kevin Murphy says there are two main things you need to rely on for an encounter - patience and luck.

Norwich Evening News: Kevin Murphy, Norfolk Wildlife RescueKevin Murphy, Norfolk Wildlife Rescue (Image: Jamie HoneywoodArchantNorwichNorfolk)

Mr Murphy, who runs Norfolk Wildlife Rescue, said he had been following the city's semiaquatic dweller for the best part of six years and that his sightings did not follow a discernible pattern.

He said: "I'd say the best time of day to see him would be around six in the morning but I've also spotted him in the very early hours before and there is no guarantee at any time.

"I've seen him in a fair few different spots, but I generally patrol along the Wensum between Bishopsgate and Fye Bridge, that stretch."

Norwich Evening News: Is this Norwich's Oscar the otter?Is this Norwich's Oscar the otter? (Image: Kevin Murphy)

The otter is often seen popping up for air along the Wensum, but also occasionally will relax on the banks, while Mr Murphy said one of the keys to spotting him is the bubbles.

He said: "If you see single bubbles popping up in one space, it's likely to be a fish. Otters are always on the move so it'll always be a stream of bubbles.

"Then you may see a hump of a back and a flick of the tail like a dolphin - it's so satisfying."

And Mr Murphy believes Oscar may not be the only one to dwell in the Wensum, having also made sightings of a female otter in the mix.

Norwich Evening News: A stretch of the river Wensum in Norwich, near NUA, where you may spot Oscar the otterA stretch of the river Wensum in Norwich, near NUA, where you may spot Oscar the otter (Image: copyright: Archant 2014)

He said: "Generally, otters are like any predator - they will find places where there is a supply of food and where another otter isn't there to compete with them.

"They are expanding creatures so likely Oscar would've been born elsewhere then fledged from his mother like birds do and mark a place as their own territory.

"However, this isn't the zoo, if you want to see him in the wild you have to be very patient and very lucky."