[1][2] An area of 8 hectares (20 acres) is a nature reserve called Decoy Heath, which is managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust.

[4] In the southern part of the site the land slopes gently eastwards within a draining gully system; the head of the stream West End Brook flows through here.

On the northern part of the site a former gravel pit, now partially infilled after it was abandoned in the early 1980s, has developed into a mosaic of shallow pools, also supporting a large pond, some heathland and scrub.

The area supports many wetland plants including bulrush Typha latifolia, common spike-rush Eleocharis palustris, as well as a locally scarce species marsh speedwell Veronica scutellata.

[4] The site is associated with a range of rare fauna, including woodlark and the silverstudded blue butterfly (Plebejus argus), both of which breed in the heathland area.