Reports of 'big cats' roaming the North-East regularly make the newspaper headlines but, although naturalists believe the sightings are genuine, they also think the creatures are not breeding but are, in fact dying out. John Dean reports.

IT was as the couple were walking along the country path that the big cat appeared 30 metres ahead of them. Silently, it loped along the track for a short while before disappearing into the undergrowth once more.

It was not a long encounter but enough for the couple to convince themselves they were watching a puma - and not in North America, but just outside Stockton, Teesside.

Reported in 1999, it is one of the sightings studied by a leading North-East naturalists' group whose findings, just released, suggest big cats do roam the North-East but are less numerous than some would suggest.

The man behind the survey believes that, contrary to claims by those who suggest the population is growing, the creatures may already be dying out.

Ian Bond, from Darlington, a member of the Northumbrian Mammal Group, which brings together some of the leading naturalists in the region, approached the research from an ecologist's standpoint, analytical and scientific.

An ecologist for a North-East council, he is more used to assessing reports of endangered mammals such as harvest mice.

He says: "The idea with the big cat sightings was to use the same criteria we use when asked to confirm the existence of something like harvest mice. When someone tells me they have seen a harvest mouse, I ask where it was, what size it was, what colour it was. From that I can determine if the report is genuine.

"I did the same with the big cat sightings. The best ones were from people who knew about animals - some of the reports came from naturalists - and were adamant that they had seen a big cat and not a large moggy. Some of the people had dogs with them, which helped them compare the size of their animal with the creature they were seeing."

Mr Bond first asked for sightings through the group newsletter in 1999 and since then has collected 32 sightings from group members and the public, which seem to suggest the presence of big cats.

He has graded nine as As, those which he says could not possibly be anything else than a big cat, and 23 as B, where there is a strong possibility but which cannot be proved beyond all doubt.

The As throw up intriguing patterns: two sightings of a panther in the Guisborough and Roseberry area of east Cleveland, two of a panther in the Hartlepool/Sedgefield area last year and the Stockton puma from 1999. The other grade A sightings were of some kind of big cat in south Northumberland and a lynx at Blanchland in the county in 2000.

Of the Bs, seven were from Cleveland, six from the Stockton/Billingham and Stillington area, four identifying a panther, one a lynx and two an unknown big cat.

Nine were from County Durham, including a sighting this year of a panther-type creature in the Delves Lane/Iveston area of North Durham, two of a panther at Bishop Middleham over the past two years, and a lynx at Medomsley, near Durham, in 2002. The rest of the Bs were in Northumberland.

Mr Bond says: "The Stockton sighting was a good example of an A: taking everything into account there was no other explanation for what the couple had seen. It had to be a puma. I don't mind if tomorrow someone takes a picture which proves this wrong but at the moment there are no other explanations for what these people are seeing. It has got to be big cats.

'FOR me, we have gone beyond the argument of 'are they in this country or not?' - a lynx was found in Cricklewood, in London recently - and have moved onto trying to assess their status and what effect they are having."

Some advocates of big cat existence suggest the large number of sightings indicate an established and growing population but Mr Bond is unconvinced.

The animals seem to have appeared when tough new laws in the 1970s placed rigorous restrictions on private animal collectors, leading to some owners releasing big cats into the wild, but Mr Bond does not believe they have become a viable population since.

Mr Bond, who says big cats can live up 12-15 years and believes some are still being kept illegally, says: "There have been reports of young animals in the North-East but if there is breeding, I do not think there is a lot of it and I do not think there is a large, well-established population.

"The reports to me have trickled in - if there were a larger population I would expect to see many more. I would be surprised if, in 50 years, there are puma, panther or lynx in the North-East countryside."

There is precedent for such a situation. An animal collector released wallabies into the Peak District, in Derbyshire, in the 1930s but they gradually died out, although there are still occasional sightings in the North-East.

Naturalist Kevin O'Hara, of the Northumberland Wildlife Trust, a Northumbrian Mammal Group member, believes the sightings are down to continued releases rather than widespread breeding.

He says: " If you were keeping a puma or a leopard you would be unlikely to report it when it escaped, especially if you were keeping it illegally.

"I think there may be the odd animal but, in places like Canada, these creatures have huge ranges half the size of England. The reports from different areas of the North-East could be of the same creature."

Mr O'Hara believes some people mistake creatures like otter and deer for big cats or are swayed because they want to see a puma.

He says: "If you only catch a fleeting glimpse of the animal running through the grass, it is easy to make a wrong identification. I would absolutely love to be in the countryside and have a puma walk across my path. Many people want to have that large carnivore out there. They want to have that mystery.

"But if there were big cats, I would expect more signs, scratching posts, droppings, smell, that kind of thing. Big cats have a strong smell, stronger than a fox, and you know if they are in an area."

Viable or not, tantalising sightings keep coming. A month ago, at 4pm in bright sunshine, a walker of more than 30 years' experience was approaching a bell-pit, part of the old mine workings in Upper Nidderdale, North Yorkshire.

The man, who is from the Harrogate area and asked not to be identified, says: "This creature walked out of the bell-pit ten yards away and looked me straight in the eyes. It was saying 'I am not frightened of you.' I have never felt scared before but I was scared then. It didn't run away and just sloped back into the pit."

He is convinced it was a bobcat, a form of lynx, and because it was so fat believes it was pregnant. Normally, bobcats live in North America and Canada but there have been rumours over recent years of them being illegally released in North Yorkshire.

The man says: "Visibility was good when I saw the creature. I can say for definite that there are bobcats in the Yorkshire Dales."