HERALD journalist Charlie Elder has travelled the length and breadth of the UK to see our most endangered birds and find out why they are in trouble – a unique quest described in his book While Flocks Last, which is published this week, writes Roger Malone.

Scrambling up mountains, tramping across bogs and trekking through snow, the 'learner' birdwatcher journeyed from Scilly to the Shetland isles, Wales to the West Country and the Highlands to the Hebrides in his attempt to track down Britain's birds of highest conservation concern – our national 'Red List'.

Meeting experts along the way, Charlie explored what was being done to help species on the brink of extinction in this country, asking whether they were worth worrying about in the first place, and also considered the popularity of birdwatching as a national pastime.

"I've always been interested in birds, but it was only when I moved with my family from London to Devon that I encountered many species I'd seen pictured in British bird books and never dreamed I would one day be spotting from my kitchen window," he said.

"I realised that up until then I'd spent more time watching wildlife on TV than actually getting out and seeing it.

"I was also conscious that many of our familiar, and not so familiar, birds have suffered catastrophic declines. We've been told we should care, but I was keen to find out why, and decided the best way was to set out to see these threatened species and meet the conservationists working to turn around their fortunes."

There are currently 40 birds whose declining numbers or range qualify them for inclusion on the UK's Red List, which is drawn up by the RSPB, the Wildfowl and Wetlands Trust and the British Trust for Ornithology, among others. They include the hen harrier, the nocturnal nightjar, the globally-threatened corncrake and the black grouse, as well as more widespread feathered friends such as house sparrows and starlings which have suffered population freefalls over recent years.

From the intensification of farming to illegal hunting and habitat changes on overseas wintering grounds, a range of factors have pushed some of our best-loved birds 'into the red', cutting numbers by more than half – in a few cases by up to 95 per cent – over the last few decades.

While some birds have become flagships for the conservation cause, such as skylarks and bitterns, others have been losing ground out of the public eye.

Armed with a field guide and a cheap pair of binoculars, and giving himself a year to track down all 40 of our Red List birds, Charlie faced a steep learning curve and a daunting challenge.

"It was about trying to be in the right place at the right time, especially as many on the list are seasonal visitors," he said. "For some of the rarer birds I had to turn 'twitcher' and race the clock to stand any chance of a sighting, while other evasive species required a more patient approach – or plain good luck! To be honest, when I set out I never realised just how hard it was going to be."

Memorable experiences during the year included joining farmers on a grey partridge 'shoot' without guns, taking a high-speed inflatable boat to see one of our rarest breeding seabirds on a protected island, accompanying a researcher 'tape-luring' a forest bird which is practically impossible to identify by sight alone, and waving white handkerchiefs on a hilltop to attract a secretive night-flying species.

While many birds in need of urgent conservation action face an increasingly bleak future, there have been success stories, as the fortunes of some species have improved. Charlie said he was determined his book should highlight good news as well as bad, and be a light-hearted read rather than an environmental manifesto of doom and gloom.

"Conservation issues don't have to cast a cloud of guilt over our enjoyment of wildlife," he said. "In fact, they can add a new dimension to our appreciation of species. Once you know something's in trouble, you can't help but look at it differently – even the humble house sparrow, which I used to take for granted.

"Every bird tells its own story about the environment, and fortunately more and more people are now listening. Certainly more and more are birdwatching, which can't be a bad thing, and one thing became evident on my travels: that all of our threatened species are worth seeing, and worth saving."

While Flocks Last is published by Bantam Press on March 12, priced at £14.99.