One of Oxfordshire’s largest sedgebeds and the neighbouring wood and scrubland is home to several endangered birds — the song thrush, reed bunting and bullfinch — and also to the less threatened reed warbler.

They enjoy a level of protection because of the inaccessible location of the Enslow Marsh sedgebed between the River Cherwell and the Oxford Canal, not far from Bletchingdon.

All four species figure on the Birds for Conservation Concern red, amber and green lists categorising how far their populations have declined over the past 25 years.

Both the British Trust for Ornithology and the Royal Society for the Protection of Birds (RSPB) supply statistics to the lists.

Song thrushes are on the red list, indicating they have suffered a severe decline in number, while the reed bunting and bullfinch are on the amber list, suggesting their reduction in numbers has been moderate. On the other hand, reed warblers are on the green list, which means they are found regularly in the countryside and are not considered to be as much at risk as the others.

The sedgebed provides important breeding opportunities for reed warblers, while the adjacent woodland and scrubland offer habitats for song thrushes and bullfinches.

Reed warblers use the site for feeding, but actually breed in the nearby reeds at the edge of the canal.

The site was also once home to water voles but they have fallen victim to the predatory American mink.

Enslow Marsh — taking in the sedgebed and the wood and scrubland — is one of the local wildlife sites in Oxfordshire that was identified from wildlife surveys undertaken by English Nature (now Natural England) and the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust (BBOWT) in the 1980s.

Since the Natural Environment and Rural Communities Act of 2006, public authorities have a duty to help conserve the biodiversity of such sites.

So Enslow Marsh now comes under the care of Cherwell District Council.

The sedgebed is a rare type of swamp-like habitat, which is seasonally flooded with water and is dominated by sedge plant.

Nigel Morris, Cherwell’s portfolio holder for rural issues, said: “Although it is one of the largest sedgebeds in the county it is a fairly small, rare and vulnerable habitat, which needs management to maintain it and to protect the species it supports.”

In the past, the sedgebed and the adjoining wet woodland and meadows would have been maintained through natural grazing by cattle, but this practice ceased about 45 years ago.

Ideally, the re-establishment of cattle grazing would be the best way to maintain the site as the animals would keep down the scrub and prevent it from encroaching on to the more sensitive swamp part of the site.

However, to bring back cows on to the land would mean the whole site would have to be fenced and a farmer found who could cope with the difficult access.

Cherwell council is considering this possibility, but until then it employs landscape contractors to look after the land.

One of the major tasks is to control the willow trees.

“Willows are fast growing and could intrude on to the sedgebed and our tree officers arrange for the work to be done such as cutting back,” said Mr Morris.

Although the sedgebed is inaccessible it can be seen by walkers along the canal towpath and there is an interpretation board nearby.

A few miles away and closer to Bicester is another local wildlife site, Trow Pool, near Bucknell, and it is owned and managed by Cherwell District Council.

In fact it consists of two pools, one larger than the other and the site is important as a habitat for small mammals such as voles and invertbrates. Trow Pool also plays a part in providing a link with other sites to enable wildlife to move and thrive.

The management of the site is fairly light and a hedgerow was planted on the western side. In the future, work to be done includes coppicing the grey willows to allow more light into the pools to benefit the aquatic life.

Bird and bat boxes have been provided on the site.