Area: 139.3 hectares.

Other Information:

Part owned by National Trust. Within South Devon Area of Outstanding Natural Beauty. Heritage Coast. Within South Hams Coastal Protection Area. Part covered by Bird Sanctuary (Statutory Instrument: 1951 No. 901). 

Statement of Interest:

This site comprises extensive reefs of interest for their intertidal plant and animal communities together with coastal sand, shingle and steep slopes of sea-cliff grassland and mixed scrub. It is also of interest for the diversity of passage and wintering birds it supports and for nesting species associated with the scrub; at least one nationally rare species of bird breeds on the site. The area has a long record of research and educational use. The landform itself is also of interest, displaying a wave-cut platform, head terrace and degraded fossil cliff line. 

The slatey Blackstone Rocks dip in a south-easterly direction, providing crevices and gullies which shelter delicate organisms. To seaward, there is an extensive wave-cut platform with numerous rock pools; some of the earliest intertidal rock transects can still be followed here. Wembury Point itself is sheltered from extreme wave action by the Mewstone and outlying reefs, whereas Renney Rocks are of quartzite and are fully exposed to wave action from south and west. This combination has allowed a wide variety of plant and animal species and communities to develop; for instance there are southern species of seaweeds, with several Gigartina and Gracilaria species on this one shore. 

The extensive weed-covered rocks exposed at low water, with patches of sand, shingle and banks of decaying seaweed washed up in stormy weather, provide feeding grounds for resident and migrant waders. At least 80 species have been recorded including curlew Numenius arquatapurple sandpiperCalidris maritimaknot C. canutussanderling Crocethis alba and bar-tailed godwitLimosa lapponica. There is a large summer flock of non-breeding turnstones Arenaria interpres.

Much of the shoreline is backed by low cliffs and slopes of scrub, dominated by european gorseUlex europaeusbramble Rubus fruticosusblackthorn Prunus spinosahawthorn Crataegus monogyna and elder Sambucus nigra. Breeding birds associated with the scrub include several pairs of the rare cirl buntingEmberiza cirlus – a species afforded special protection under Schedule I of the Wildlife and Countryside Act, 1981 – and large populations of yellowhammer E. citrinellalinnet Acanthis cannabinastonechat Saxicola torquata and white throatSylvia communis. The Mewstone islet also enables birds to nest comparatively free from disturbance. The very rare Dartford warbler Sylvia undata – another Schedule I species – defends territory on part of the site and may breed. The scrub is also used as a staging post by migrant birds, especially warblers. Black redstarts occur along the coastline. 

Some of the earliest SCUBA studies of marine species underwater, which complement those of the foreshore, were carried out nearby. The sea and seabed in this vicinity is now a voluntary marine conservation area, where study is continuing.