January 2 2010: The comedian who takes his pet cockatoos for walks in the park is bringing his passion for twitching to TV

Bill Bailey sits in a collapsible camping chair, surveying the scene on the Isle of Mull. Otters frolic on the shore and a double rainbow dips into the sea as Bailey, his long wispy hair blowing in the gentle breeze, reflects on his love of birdwatching, one of his many grand passions. He is in Scotland filming a new birdwatching series for Sky and keen to spot today’s bird, the sea eagle.

The last time I interviewed Bailey, in 2002, a pet cockatoo was grooming his beard. He told me how he and his wife, Kris, took their pair of white cockatoos to the local park on bright pink and green leads, as though it was no different from walking a dog.

Now, sitting by a campfire, Bailey considers his reputation. “I suppose I am eccentric. Sometimes you just have to admit these things. Yet I fight it so much. I want to shout out: ‘I’m perfectly normal!’ I say to my friends: ‘I don’t know why you people don’t think I’m not like everyone else.’ ” He pushes his hair back and laughs. “Then they point out that I’m feeding a chameleon or am about to film some rare goose, both of which seem normal to me.”

Bailey loves animals. He’s not overly sentimental about them — he eats meat — but it sounds as though he lives in a mini-zoo. Or, rather, he has turned his garden flat in Hammersmith into a haven for animals and insects. The cockatoos are still alive (he calls them “young striplings who can live to 80 or 90 in captivity in South London”), alongside four dogs, a cat, a rabbit, a guinea pig, some fish and a couple of Bali starlings.

His six-year-old son, Dax, loves bugs and has his own collection of Madagascan hissing cockroaches and African land snails. There’s also a chameleon roaming around a small tree in the bathroom. “We had a breeding pair but the female ran off to escape the male’s attention. Apparently it’s quite common, as the males are very demanding.”

When I start giggling at the idea of sex-on-demand chameleons in his bathroom, he keeps the story going. “We feed him live crickets every day. I shield the cricket’s eyes so it can’t see what’s coming. It’s prehistoric: the chameleon’s mouth slowly opens and this huge tongue whips out.” It must be interesting when people come over for dinner. He laughs. “Particularly when you forget to mention the chameleon and then there’s a muffled scream from the bathroom. Come to dinner, but beware!”

He concedes that his neighbours consider him eccentric. As do the parents at Dax’s local primary school. At the age of 2, Dax was taken to the jungle in Sumatra, where he camped with his parents under tarpaulin. “We took precautions. We were sensible with gels and cleaning. The locals are so far away from medical supplies that they can’t afford to get ill. I do think it toughens your constitution. Over the years I’ve become less prone to minor infections. I hate getting ill now. It drives me nuts.”

Next the family are heading to an Indonesian island to climb a volcano. “Dax was too young to climb it last time we went; he’s old enough now. I think such trips help a kid’s confidence. He’s hardier, too.”

As you might guess, Bailey isn’t one for the beach. He’d rather have a daily purpose to his time away, such as tracking down Wallace’s standard-wing bird of paradise. He has been birdwatching since he was a kid, and remembers being able to pick out grebes and mallards from an early age. He lived with his parents — his father was a GP and his late mother a ward sister — in Keynsham, between Bristol and Bath. Weekends were taken up walking and birdwatching. Although birdwatching is now fashionable, it’s clear that Bailey was already unusual as a child.

Part of what propels Bailey in daily life is the thirst for knowledge that he inherited from his parents. He was always one of the smartest kids in his year at his direct-grant school but never quite made it to Oxford or Cambridge; he was as much a performer as an academic. He spent the early Eighties touring with a Welsh experimental theatre group, played keyboard in a jazz trio and slowly realised that he’d never fulfil his dream of becoming a rock star. Instead he discovered that a quirky combination of comedy, music and theatre allowed him to exploit all his talents.

Bailey isn’t a show-off, but neither is he interested in hiding his big brain. He intensely dislikes “wilfully anti-intellectual comedy”, in which stand-ups dumb down for easy laughs. He argues that comedy allows the opportunity to discuss any subject on any level, and he should know. His comedy has covered everything from the post-Structuralists to, on his last tour, an off-beat guide to orchestral instruments. Bill Bailey’s Remarkable Guide to the Orchestra, which took in a night at the O2 arena last month, simply confirms that the bearded one is right: there is a wide public appetite for smart comedy.

Bailey’s producer comes over and tells him that it’s time to drive to the next location. The teams — captains Jeff Green and Alex Zane, special guests Donal MacIntyre and Jayne Middlemiss — are already at the loch, each trying to photograph the sea eagle first. I hitch a lift in Bailey’s family Volvo and, on the way, he talks about how the five-week shoot has so far been blessed by amazing weather.

As Bailey drives slowly along the country road he waves at oncoming cars. It seems a little regal, but I think nothing more of it. It’s only later, when he is gazing through a pair of binoculars at a sea eagle riding the thermals, that I remember the waving. It turns out that, a few nights earlier, he made an impromptu appearance in the local pub, playing guitar and singing folk songs.

Most of the island, it seems, turned up to watch. “We rocked the whole of Mull! If you consider yourself an entertainer, you should be able to entertain any audience, anywhere in the world.”

He stops short and smiles. “Did you hear that? Did you? It’s a lovely little wren! Every time we see an eagle, there’s a wren going, ‘What about me?’ ”

Bill Bailey’s Birdwatching Bonanza, Friday, January 8, 2010, at 8pm on Sky1 HD and Sky1