Iolo Williams seems remarkably calm about the coming four months of sleepless nights and often futile waits, but that's not surprising - his mind is on other things. As he speaks his eyes are upturned, scouring the surrounding trees while rooks caw in the valley below. We are in "a known goshawk wood" in mid-Wales at the beginning of his working year - spring.
As species officer for the RSPB in Wales, Mr Williams is responsible for protecting many of Britain's rarest birds and the breeding season is by far the busiest time of year: "It kicks off properly in April," he says. "We're most interested in red kites, but it usually starts with ravens. They're earliest of all and collectors come in March to watch other birds pairing up. While pinning down kite nests for a later raid, they collect ravens' eggs - get their hand in, so to speak."
Williams tries to be first to identify potential nests. This allows him to mount guards: "We divide Wales up between about 20 unpaid kite wardens who range from retired people to a solicitor," he explains.
Once the sites have been found, the most vulnerable birds may have to be helped: "Eggers care nothing for birds and nothing for the countryside," he continues. "As far as I'm concerned, egg-collecting is nothing short of mindless vandalism."
Worse, eggs are valued in direct proportion to the rarity of the bird - and kites are among the rarest. Well-known nests have to be watched, in some cases 24 hours a day. This seems to be working well: "We have got away lightly the past few years because the army has helped guard nests and the thieves know it," says Williams. "So far we've only lost a couple, but before that it was anything up to 10 a year."
Mind you, even if a clutch hatches, more help may be needed. Kites are notoriously bad parents - one pair, for example, persistently nests above a lay-by every year, only to desert their young as the tourist season begins. So the chicks have to be hand-reared and returned to the wild later. But the effort is worthwhile - kites have increased from 15 individuals at the turn of the century to last year's 120 pairs: "This year I expect to find more than 140," Williams smiles.
Eggers, though, are not the only villains. Thieves steal peregrines to sell to falconers while pigeon fanciers often blame peregrines for high losses among their flocks. Williams comes in for his share of hatred, too. A few years ago he found a peregrine eyrie where the clutch had been replaced with hens eggs. "The words 'Fuck you Iolo' were written on them in lipstick - I know who did it and he's not a man to be tangled with."
Williams stiffens: "There we are - that's it." He points to an untidy mass against a larch trunk. "This is an active goshawk nest," he says confidently. "And it was used last year, too - look here's a bit of shell."
Pleased to have pin-pointed the nest, he explains that the breeding season is the only time when a census can be taken of many rarities such as these goshawks. He also counts more familiar birds: "Common species are important environmental indicators," he says. "For example, lapwings have dropped from 7,000 pairs to well under 1,000 pairs in just eight years, and skylarks are becoming rare in lowland areas."
Every spring Williams recruits fieldworkers for RSPB studies: "This year we're surveying the Brecon Beacons to find ways of making money in the uplands without sheep," he says. "And we're doing a farmland study to check the value of environmental subsidies."
Although much of the groundwork is delegated to others, it results in long hours for Williams, too: "I don't expect to be in the office more than twice a week," he says. "If I ask someone to be up at dawn then the least I can do is to be out there too, particularly because we're increasingly using volunteers."
From March to July the day begins horribly early: "If you're monitoring black grouse, for example, you're up at 2am to catch the males displaying at dawn. Then I'll spend five or six hours with my field workers. Afterwards I'll aim for an early night, but of course it doesn't always work out like that because owls and nightjars need to be counted in the evening."
In spite of the energy he puts into his work, his efforts are frustrated by factors beyond his control. Overgrazing is worst: "There were 4 million sheep in Wales before the war - now there are 11.7 million," he says. "The result is fields as smooth as a bowling green and a huge loss of heather."
The answer lies in cutting back on sheep numbers, says Williams, but the problem is more complicated than that: "Rural communities are the backbone of our culture," he says. "We don't want to lose that, but we want the birds back. We should get the farming unions together with our policy people and work out solutions together."
As the year progresses, the pressures to be out and about reduce, but the hours remain long: "The fieldwork eases off in July, but then I'm busy writing up reports, after which I plan next year's research and working out budgets."
He pauses by the car parked inconspicuously in a lay-by: "I love my job, in spite of its drawbacks - I'm captain of the local rugby club, but there's precious little time for games." There are other disadvantages, too, such as the 2am call from the police one Sunday morning: "They'd searched a car and wanted me to identify some eggs. I'd had a few beers with the team and was over the limit, but they were insistent and a squad car came 40 miles to pick me up. Now for five months of the year I can't even have a drink at the weekend."
Nor does he get paid overtime to compensate for the hours, but Williams doesn't mind: "Doing something I believe in while being out and about in such a beautiful country is bonus enough," he says, his eyes still glued to the skies.
EGGERS: WHAT ARE THEY AFTER?
l Eggs have no commercial value. Usually they are gloated over privately - although occasionally other enthusiasts may be invited for a viewing.
l One man was caught in 1989, holding 16,500 illegal eggs.
l The RSPB has 500 known collectors on its database. Most eggers keep scrupulous records. One apprehended recently had diaries dating back 10 years, complete with grid references to important nest sites, clutch sizes and laying dates. He revisited the same areas on almost exactly the same day annually.
l The red-backed shrike was probably finally exterminated in Britain by collectors. The last regular pairs disappeared in 1988.
l True eggers take all the nest contents - particularly large clutches or strangely-marked eggs, removing embryos by piping in acid and syringing out the contents.
The egger's favourites
l Ravens (5,000 pairs): early March raids on these, the first layers, double as reconnaissance for future raids
l Scottish golden eagles (420 pairs): late March
l Welsh red kites (160 pairs): early April
l Choughs (280 pairs) - our rarest crows, nesting on Welsh and Scottish cliffs: late April
l Scottish red- and black-throated divers (1,400 and 155 pairs respectively): highly prized because of their beautiful eggs: May
l Ospreys (100 pairs) - no longer as rare as they were in the 1950s, but their eggs remain highly valued for the markings, eight clutches were lost in 1995: May
l Dotterels (155 pairs) - moorland waders from the Arctic are raided in Scotland: May/June
l Avocets (500 pairs) - the RSPB emblem: May/June
l Cirl Buntings (230 pairs) - fast declining in the West Country: May/June