It's a wild birthday party!

This month marks the 20th anniversary of Oxford Urban Wildlife Group. Formed in May 1988 to encourage wildlife within the city, its major achievement has been the creation of Boundary Brook Nature Park.

Originally the site of derelict allotments, Boundary Brook has doubled in size to become a six-acre peaceful oasis off Oxford's Iffley Road.

An amazing range of habitats created provides a permanent home for a large range of native mammals, birds, insects and plants.

A family of foxes has moved in, while in the summer the meadow is buzzing with bees and there are many breeding butterflies. The air is full of birdsong from common garden birds while sparrowhawks and red kites watch from above. The pond attracts visitors from the river like herons, kingfishers and mallards. One year there was a visit from a rare bittern and another year a wryneck.

Led by a small band of enthusiasts, Pat Hartridge, Janet Keene, Kathy Chicken and Delia Twamley, the 160 members of OUWG have worked tirelessly to create these habitats, though the committee would be first to praise the dedication of two stalwarts - Peter Wilkinson and Alan Hart - in the daily hard graft that is needed.

Janet Keene said: "We are very delighted to have reached our 20th anniversary. Unlike some groups, we have persisted and just gone from strength to strength."

The park boasts a native woodland, a small traditionally managed hay meadow, a miniature flower-rich cornfield, a hazel coppice, a bird orchard as well as a marsh and large pond.

Nearly 1,000 birch, oak and ash trees have been planted on land previously covered in brambles as part of a four-year project with the Oxfordshire Woodland Project. It will eventually become the biggest wood in Oxford. A demonstration wildlife garden and an organic kitchen garden show visitors what they can do at home to attract wildlife to a city garden. Creating and maintaining these habitats have given valuable experience in conservation techniques to many individuals and visiting groups.

School groups undergo projects and a favourite activity is pond-dipping. On the group's regular open days, visitors are shown around the nature park and often the experiences of the schoolchildren persuade parents to join their children on a tour. Craft days, picnics and moth-trapping events also prove attractions.

Boundary Park may be the group's crown jewels but it undertakes annual surveys of other wildlife sites around Oxford, including those that might be under threat from development.

The most recent survey was an annual count at Osney Mead of fritillaries, the county flower and chosen as the emblem of the group.

The next one is on Thursday at Cripley Island, a small area off Port Meadow. Fruit trees were planted there some 50 years ago and it has since become a haven for invertebrates and other wildlife. It is under threat from those who would like to clear the site for allotments and the OUWG believes it is a conservation priority as an ancient orchard.

OUWG runs a programme of talks on many topics and leads guided walks through the year to some of the many green spaces in Oxford.

As well as practical events, the group gives advice on wildlife gardening to visitors to the nature park or at stalls at other city events. They have even been consulted by other groups and schools about creating similar wildlife sites.

The next open day at the nature park is on Sunday, June 1, from 2pm to 5pm when visitors can see the early summer flowers, butterflies and birds. There will be pond-dipping, guided walks, plant and book stalls. Admission is free.

Working parties take place every fortnight and the next one is on Sunday between 10am and 1pm.

The park is off the Iffley Road, opposite Donnington Bridge. It is at the end of Boundary Brook Road at the beginning of the cycle track. There is parking and is easily reached by bus.

For further information contact Janet Keene on 01865 820522, email info@ouwg.org.uk or visit the www.ouwg.org.uk website.