Victory declared in Great Butterfly Hunt

It has taken five months, but now The Independent has achieved its aim of spotting every one of Britain's 58 species in a single summer.

It finished on the last day of summer. The Independent's Great British Butterfly Hunt, our attempt to see and report on every one of the 58 British butterflies species in a single year, came to a successful climax last Monday, 31 August, when we finally sighted the 58th – the clouded yellow.

The clouded yellow is a striking insect and one of the two migrant butterflies which cross the Channel every year to join us from continental Europe (the other being the painted lady). It had been an elusive species to track down, with several trips in search of it proving fruitless.

While painted ladies this year poured into Britain in perhaps the greatest numbers ever seen – there may have been over 20 million – clouded yellows, which wander about the countryside searching for fields of clover and other leguminous crops, have been a much rarer sight.

But on the stroke of a sunlit noon on Bank Holiday Monday, on a scrubby, wildflower-rich corner of the South Downs above Steyning in Sussex, those unmistakable, bright sulphur-yellow wings flashed over the browny-pink wild marjoram and pale blue field scabious flowers.

We had done it.

We hope that it has given a sense of the richness and value of our wildlife to have seen and reported on every single one of our native butterflies, from rarities such as the swallowtail, the heath fritillary and the large blue, to common but still very beautiful species, such as the red admiral and the peacock.

It has certainly told us a lot about the state of the natural world, as the presence and the visibility of butterflies is one of the best indicators of the health of the countryside as a whole.

British butterflies have had quite a good year in 2009. It was not brilliant – apart from the painted lady explosion, which was an exceptional natural event, with a single field in Sussex found to contain perhaps a quarter of a million pairs of those salmon-pink wings. But it was infinitely better than the two years which preceded it: the washout summers of 2007 and 2008. Their endless downpours sent several threatened species, including the wood white, the Duke of Burgundy and the high brown fritillary, plunging to their lowest levels on record.

Although hardly the "barbecue summer" that the Met Office had so confidently predicted in its long-term forecast in April, there was enough fine weather in May and June to allow many species to emerge and lay their eggs in good numbers.

The three rare ones mentioned above all made recoveries, as did the once-common small tortoiseshell, whose numbers have in recent years been decimated by a parasite.

The heath fritillary, another rarity, also had a very good year, as did a number of the more common butterflies, including the peacock, the speckled wood, the silver-washed fritillary and the ringlet.

Others were not so fortunate. Four of the moth-like skippers, the large, the small, the silver-spotted and the Lulworth skipper (the last a speciality of Dorset) were down in numbers, as were the clouded yellow, as mentioned above.

Another difficult-to-find species was the red admiral.

Formerly a migrant, the red admiral, whose striking wings of black, white and scarlet make it many people's favourite butterfly, has increasingly been overwintering in Britain because of our warming climate.

But the snow and intense cold of February seem to have killed off the wintering butterflies and for some reason fewer migrants got here later from across the Channel.

We found it in the end, though, as we managed to find all the others, from the chequered skipper in Argyllshire (it's now extinct in England) to the Glanville fritillary on the Isle of Wight, in a quest that many Independent readers also took up.

Our invitation to join in the hunt generated widespread interest. Some people's totals were not large, but they had been compiled with evident pleasure. Judy Halliday of Caversham near Reading wrote that "The article in The Independent coincided with my decision to retire in April. It was quite a traumatic time and observing small, beautiful objects like butterflies served to help me to get over the bigger decisions in my life." Judy's total of 15 included less common species such as the dingy skipper, which likes chalky hillsides, as well as the jewel-like small copper and the orange tip.

That was the sort of total a number of readers came up with – it's the kind of figure you can see by being observant, without making special trips. Laura Lesley from Sussex recorded 107 sightings of 16 species, including the lovely marbled white, while Emma Lambe saw a total of 18 species, including the uncommon small blue, plus an unidentified skipper, around her 200-acre organic farm near Ross-on-Wye, which is specially managed for wildlife.

To see a lot more than that, you needed to be something of a true butterfly enthusiast. Richard Parkhurst, for example, from Waterlooville in Hampshire, who does surveys as a volunteer for the charity Butterfly Conservation, managed to see 31 species, including the once extinct, now reintroduced and still very rare large blue, which he found on one of its reintroduction sites in Somerset. In fact he saw six of Britain's eight blue butterfly species. And he was doing well, according to Butterfly Conservation's chief executive, Martin Warren: "To see over 30 species in a summer is good. To see over 40 species is very good, and anything over 50 means that you're doing exceptionally well."

Not many people breached 40, it has to be said. One was Professor David Newland, author of the guide Discover Butterflies in Britain, which gives more than 60 butterfly-finding locations: he spotted a total of 41, including real rarities such as the Duke of Burgundy, and 17 species in his village garden in Ickleton in Cambridgeshire alone; but he asked not to be considered for the prize (it would hardly be fair, would it?).

Yet the winner very nearly scooped the lot.

Andy King, 61, head of biology at Friern Barnet School in North London until his retirement last year, found that this summer he at last had the time and the freedom to look for butterflies seriously; he managed 57 out of the 58.

The species which eluded him was the chequered skipper. He found that when he was able to go to Scotland, he had missed it. Yet he meticulously documented and photographed all the others, with the most difficult being the mountain ringlet – he had to climb three Lake District peaks before he found it (The Independent only had to climb one).

"To see them all in one year was a logistics exercise," he said. "You had to find out where and when the species could be seen and then get there when the sun was shining.

"There was a certain amount of money involved, and a lot of travel – I saw them in 15 counties, never mind the counties I travelled through to get to them."

Andy's prize was a safari with Butterfly Conservation (plus lunch) to find the brown hairstreak, one of the hardest of all our species to see. In fact, he had already seen it, at Whitecross Green Wood in Oxfordshire, (though he was very keen to seek it out again).

But The Independent had not seen it. It was species 57 on our target list, and we still had two to go when Andy, myself and Martin Warren set out from the village of Steyning last Monday morning under the expert guidance of Neil Hulme, chairman of Butterfly Conservation's Sussex branch. It was one of those days when everything seems to go right, for as soon as we got to the site Neil had in mind, a strip of ash wood with an understorey of blackthorn, we found a female brown hairstreak. Normally both sexes haunt the treetops and are virtually impossible to see, but in the morning the females come down for a couple of hours to lay their eggs on blackthorn stems.

They are much more striking than the plain-coloured males: chocolate brown, with broad orange-golden bands across the forewings. I was taken aback; it was the most beautiful British butterfly I had ever seen.

That was at 11.20am. We watched it, and then another one, for 20 minutes, and then began a final hunt for the clouded yellow, The Independent's one remaining unseen species. When Martin Warren's shout signalled we had found it, with half a day of the summer left, you may imagine that the feeling was one of elation.