Northmoor Trust at Little Wittenham has ideal conditions for the Great crested newt to thrive and has led to a conservation project, writes ELIZABETH EDWARDS

The world's largest population of Great crested newts is to be found in the UK. The amphibian is a protected species in this country and Steve Gregory, a researcher at the Northmoor Trust, Little Wittenham, has been active in a local project to conserve them.

The trust site has the conditions for the Great crested newt to thrive, with its mature woodland and deep ponds providing an ideal home. They prefer the larger, deeper ponds, said Steve.

The ponds may have been providing this habitat as far back as the 9th century when the land was owned by Abingdon Abbey and when they may have been the fish ponds of the monks.

During the 1970s, they silted up but the then owner cleared and excavated them. The populations built up again, taking advantage of the woodland.

Great crested newts are much larger than the common smooth newts yet both can be found in the same ponds. The male has the jagged dorsal crest, and the larger female only a slight indentation.

For their winter quarters, they choose woodland and areas such as rough grass and scrubby ground. They spend the winter burrowed into piles of logs, stones, or tree roots. The Northmoor Trust's clay soil provides useful crevices.

When the newts begin their return to their breeding grounds it depends very much on the weather, said Steve. Research has shown that five consecutive nights with the temperature up to 5C should trigger activity, especially if it also offers the damp conditions that Great crested newts favour.

While February and into March is at present the starting point, global warming could bring changes to this, Steve observes. The fact that the newts are so well hidden during their hibernation emphasises the need for expert investigation when a site is being proposed for development.

A colony of 32 Great crested newts was recently discovered before work began on a major development project at RAF Brize Norton. Natural England was called in to advise on the creation of an area where the newts could be safely relocated. The more involved fingertip searches, by torchlight, as each was gently removed and placed in its new home. The newts show a homing instinct but once the spring journey begins it may not be continuous. If the weather changes, they may stop en route and crawl under a lodging place such as a log.

"They know where they are going," said Steve. "They remain faithful to both their ponds and their hibernating grounds."

This loyalty may waver. If a new pond has been dug during their hibernation the newts may decide to stop there if it provides a shorter journey.

"They can sense water 50m away, so if they sense water in the vicinity, they will change direction and head over there."

The hibernation places can be 200-300m from the ponds. For this reason, protection zones on development sites have a safe area covering 500m.

Most of the newts stay at their ponds for the summer and early autumn, but, says Steve, some may have different ideas and only stay for a short time.

Great crested newts have another pecularity - each has a different pattern in the colouring on its underside.

"It's like a fingerprint," said Steve. While the back is dark, usually black, the underside is orange with black stripes. It is the pattern of these stripes that is unique to each newt.

This orange is the classic coloration warning to other species - "don't eat me, I'm poisonous". "Orange signals danger," said Steve. If threatened , the newts will display this colouring to predators. Their tadpoles, however, do have more successful predators, the larvae of dragonflies and waterbeetles and the adult beetles.

The Great crested newt lays up to 200 eggs on a leaf - those of the water forget-me-not are a favourite, says Steve. She then folds back the leaf to cover the egg. "It takes an awful lot of work." he added.

For one aspect of research at the Northmoor Trust, leaves made from pieces of black bin-liner attached to stakes are placed in the ponds. The newts appear to appreciate this ready-prepared 'plant' and reward the team by laying eggs, folding the 'leaf' over several times.

As a result of predators and a lethal fungus found quite widely, only about half survive. These are, however, long-lived creatures. They can live for up to 20 years in captivity and in the wild as many as ten years. It can take three or four years for the young to reach maturity.

The length of time a colony may survive depends on whether or not it is isolated. If there are no neighbouring ponds, colonies will lack sufficient genetic population mixture to survive for more than 25 years.

"Lots of ponds keep the population healthy," says Steve. Following the loss though, another colony will move in. "The ideal, however, is a habitat with sufficient ponds, each 200 to 300m apart," said Steve.

There are fewer habitats nowadays. Ponds used for the watering of livestock have tended to disappear from farmland. At the Northmoor Trust, however, the unsuitability of the land for some types of agriculture means that they reap the benefit.

The period of migration from hibernating grounds to ponds is an opportunity for the conservation teams to carry out their count of numbers.

Trough traps, sections of drainage pipe with a slit cut along the top, are laid 10m apart between the two places. From the traps the newts are retrieved, counted and released. The 10m spacing means that about ten per cent of the population is likely to have fallen into the traps, which means a population of around 3,000.

One year, every newt trapped was photographed. On a rainy day in March this could be about up to 100 a day, but account is taken of the fact that sometimes the same ones maybe be caught more than once.

Members of the public can sponsor the conservation work. Details are available on 01865 407792 or on the website, www.northmoortrust.co.uk