Few of his fellow ornithologists might agree with Rory McGrath's views on birdwatching.

"Well, it's a dull subject unless you do it," he says, frankly. "One thing I have found is more people do it than you think - it's like looking at porn on the internet - no-one ever talks about doing it, but if you mention it...

"A similar thing is liking Leonard Cohen; if you go to a dinner party and say 'I like Leonard Cohen', other people will say 'oh actually I like it as well, I was listening to it only the other day' - people come out; it's the same with birdwatching."

He adds: "What I'm trying to say is it's not instantly cool, it's not like F1 racing... it's 'oh I'm going birdwatching, I'll put my anorak on..'; I suppose it's getting more popular now because nature is 'in' and conservation is so big now - every other programme is about rescuing a species or animal - so it's not quite as embarrassing.

"Unfortunately - or fortunately - Bill Oddie is the public touchstone of what birdwatching is, and he's very, very knowledgeable but if your perception of birdwatching is just Bill Oddie, you have a skewed view of it."

While he won't put himself in the heady echelons of 'twitchers' - the really serious breed of birdwatcher - McGrath will happily admit his passion for ornithology, documented in his semi-autobiographical debut book, Bearded Tit - A love story with feathers.

Chronicling his childhood in Cornwall to his time at Cambridge University and his first true love, JJ, to his present day life, birds and birdwatching are a recurring theme.

"I could have written a sort of 'Confessions of a Birdwatcher' which could have been full of wacky things like me falling into the river when I was too busy looking at birds; it could have been quite Rough Guide or Bluffers' Guide sort of thing, but it turned out much more personal than I'd planned," says McGrath, best known to many as a regular on shows like QI and They Think It's All Over.

"I'm not one of those sad anoraks," he is quick to point out. "But I do like being outdoors and I like identifying things.

"In a way ironically it turned out to be more autobiographical than I'd expected but also more 'birdy'," he smiles. "By the time I finished it I thought 'actually it's too much autobiography and about my love life' and then I re-read it and thought 'actually no, I think it's too much about the birds, perhaps we should cut out all the bird bits.'

"Much to my publisher's irritation they said 'oh do about 100,000 words and that's fine', but all my training, all my instincts and my experience, especially writing comedy, is you write something like a four minute sketch and you want to make it into a better three minute sketch; if you write a joke you want it to be as crisp as possible," he adds.

"So I tend to want to make things shorter and more efficient and neater - so I wrote 100,000 words and the publisher was delighted and then I went through it and got it down to 80,000 and he said 'no Rory - stop!'"

McGrath reveals plans are afoot to film another Three Men In A Boat show for the BBC - this time he, Griff Rhys Jones and Dara O'Briain heading to the waters around his native Cornwall in a pirate ship.

Right now, however, the 52-year-old funnyman is busy promoting Bearded Tit, with book signings, TV and radio appearances - and a return visit to the world famous Hay-on-Wye book festival.

"I did it last year and we did a bit of a joke book signing," he recalls. "I thought I'd just sit at a table and I hadn't even started writing the book, so I had an empty table and people brought up other books for me to sign... publicising this book and I hadn't even written a word - and now I'm back a year later actually publicising the real thing.

"Of course I've got to do the prostitution bit, going on every possible chat show, radio show or cookery show," he chuckles. "'Today on Saturday Kitchen we've got Rory McGrath whose book's come out around now'; getting on breakfast sofas 'oh it's lovely to have you here Rory, 'cos normally you despise this programme, but you're selling a book'... 'No, I love this programme, Lorraine...'"

When he's not birdwatching and sitting on breakfast sofas, Rory's other big passion is football - Arsenal to be precise. When he speaks to CityLiving, it's the morning after the Gunners' 6-2 thrashing of Derby County:

"We can start talking about Arsenal again without having to say it's the worst season ever - we realise actually that we're going to win the championship ," he says, tongue placed in cheek.

"All we have to do is win our games and hope United and Chelsea lose their two - what could be simpler?

"What are you - Birmingham or Villa?" he adds.

"I have a friend called Steve Knight who's a Blues fan, he's one of the founders of Who Wants To Be A Millionaire? and he said to me he can stand at New Street Station and watch people coming in and he can tell just by the way they walk whether they're a Villa or a Birmingham fan."

Or a birdwatcher, maybe...

* Bearded Tit - A Love Story With Feathers is out now, published by Ebury Press. Rory McGrath will be appearing at Waterstone's, High Street, Birmingham, on May 22 at 6.30pm.