A SURVEY detailing how many different types of butterfly species there are in Hartlepool is under way.

Volunteer warden Gary Lister has taken on the task of assessing how various species of butterfly are responding to the on-going transformation of Summerhill, a 100-acre countryside site on the western edge of town, which is being developed by Hartlepool Borough Council for sports, outdoor pursuits and wildlife conservation.

Mr Lister, who is taking a part-time environment and development degree at Sunderland University, can often be seen carrying out his count at the site, which is due to be designated as a Local Nature Reserve by the council later this year.

His survey is being conducted under strict guidelines to ensure it can be replicated each year under the same conditions. Counts are carried out weekly, from April to September, on a set route, and take into account factors such as wind speed, temperature and percentage of sunshine.

Mr Lister said: "Butterflies are very sensitive to the environment and are excellent indicators of change, even at a local level.

"We might expect to see changes at Summerhill in coming years, including colonisation by ringlet butterflies with the development of woodland and the arrival of the common blue butterfly due to increases in its food plant."