FOR Sir David Attenborough, even with 40 years of wildlife broadcasting behind him, it was a familiar reaction by the BBC management.

"When I came up with the idea for Life on Earth, it was the same,'' he says. "I remember one senior BBC boss saying: `A 13 part series starting with green sludge and working up - and you expect to get people excited with that? It can't be done'."

Well, Attenborough, now 72, has proved time and again that it can be done.

With his unshakeable enthusiasm and the famous whispered urgency of his narrative, Attenborough has enchanted and educated television viewers around the world with, first, Life on Earth, then The Living Planet, The Trials of Life and the Private Life of Plants - proof that the Leicester- born broadcaster definitely does have the uncanny ability to make green sludge interesting.

And he is at it again, this time looking skyward, with a 10-part series on The Life of Birds, and early indications suggest that the series is going to be a blockbuster.

Work on the programme took three years and spanned 42 countries and Attenborough alone flew 256,000 miles in its making - the equivalent of travelling to the moon.

But what should have been the crowning achievement of his career was marred by tragedy. Almost 18 months into filming, Attenborough was in New Zealand when he was told that Jane, his wife of 47 years, had suffered a brain haemorrhage. He rushed home immediately.

"She never recovered consciousness, but she knew I was back because she clasped my hand,'' he said. She died one day short of our 47th wedding anniversary.''

He adds simply: "It was a very happy marriage.''

The strength and devotion of the marriage was, in fact, legendary. Lady Attenborough, as she became known after her husband was knighted in 1985, did not accompany him on his film trips, but never failed to meet him from the airport when he returned home.

She endured the inevitable long absences which his foreign film commitments forced on them, and combined the raising of their two children, Robert and Susan, with the running of her husband's business and household finances.

What Attenborough misses most about her now, he says, is her `presence', but he takes great comfort in the memories of her which permeate their home in Richmond, south west London.

With typical commitment Attenborough completed the series, partly as a result, no doubt, of his fascination with the subject matter.

He says: "I am fascinated by what birds do and I like to speculate about why they do it. That's what the series is about. I have come away from the series with a greater insight and sympathy for birds.

"We tend to take them for granted, but when you look at them in detail, they are absolutely extraordinary things. There are birds who fly from the north to the south pole; there are even birds who remain on the wing for three years, non-stop.''

Other wonders are on display; Attenborough shows us how the Japanese carrion crows have reinvented the wheel - by using cars stopping and starting at traffic lights to crack the shell of nuts; he shows us how the Australian lyrebirds can perfectly mimic the songs of other birds and modern sounds, like car alarms, camera lenses and chain saws - an ironic talent, as Attenborough confirms. …