Natural England - Cavenham Heath NNR

Cavenham Heath NNR

Much of Cavenham Heath NNR is typical Breck heathland with dry, acidic sandy soil supporting acid grassheath, heather heath with patches of bracken and sand sedge. In addition there are riverside meadows, woodland,wet woodland scrub and small areas of fen.

Cavenham Heath NNR

County: Suffolk

Main habitats: Lowland heathland

Why visit: Cavenham Heath NNR is 204 hectares and lies in the south-west of Breckland. The heath is a Site of Special Scientific Interest and in addition most of the site is a Special Area of Conservation: (106kb)pdf document (SAC) for its heathland habitat.The whole site is an internationally important breeding area for rare ground nesting birds, including woodlark and nightjar, and as such has been declared as a component part of the Breckland Special Protection Area (SPA) under the European Birds Directive.

Natural England's aims are to manage the heathland and associated habitats to maintain and enhance the rare flora and fauna of the site.

Star species: The wide range of habitats supports many uncommon plant species, including mossy stonecrop, annual knawel and suffocated clover. There are good populations of many butterfly species, including small copper, small heath and grayling. Over 400 species of moth have been recorded, including the rare lunar yellow underwing and forester.

There is a healthy population of adders on the Heath, best sighted at the start of the warmer Spring weather, from late February onwards, which tempts them out from their winter slumber.

Well over 100 bird species are recorded annually, and breeding species include nightjar, woodlark and stonechat on the heath, woodcock in the damp woodland and grey wagtail, kingfisher and nightingale along the river Lark. There is a regular pre-migration roost of stone curlews in August and September, in recent years numbering over 100 birds.

Seasonal highlights


There is a good population of Britain’s only poisonous snake, the adder, on the Heath. They’re best seen at the start of the warmer spring weather, often as early as mid February. This is when they emerge from winter hibernation and come out to bask on sunny days.

Spring also brings the lilting song of the woodlark. They return to the reserve to take up territory quite early in the year. Many other birds are on the move- redwings and fieldfares, who come to the UK for the winter are flocking ready to migrate to breed in northern Europe.

At the same time warblers, nightingale, tree pipits and the nocturnal, insect-feeding nightjar are returning to breed here, having overwintered in southern Europe or Africa. The wheatear is another returning migrant bird – formerly a regular breeding species on the reserve it has been lost throughout Breckland in recent years, but is still common on passage in spring.


There are swathes of colour as a succession of wild flowers come into bloom. From white of stitchwort, pink of storks-bill, reddish-brown of sheeps- sorrel to yellow of mouse-ear hawkweed the heath can look stunning, and especially so when the heather comes in flower later in the summer.

The abundant wildflowers attract insects in profusion – bees and butterflies abound, with good populations of small copper and small heath, plus brown argus and the uncommon grayling in smaller numbers. Green tiger beetles can be found on sunny, bare patches of ground along the heathland trail and the metallic green forester moth can be found on the flowers of ragwort, thistle or vipers-bugloss.

Along the River Lark grey wagtails usually breed near Temple Bridge and there is always a chance of a kingfisher flashing by. Reed and sedge warblers chatter amongst the bankside vegetation. Dragonflies and damselflies begin to appear in April and May – the gorgeous banded demoiselle can be common along the wetland trail, and in the fen emperor dragonfly and black tailed skimmers hunt other flying insects on the wing.

A visit towards dusk on a warm summer evening may be rewarded with views of displaying woodcock over the woodland, uttering their strange grunt-and-squeak calls in territorial flights known as roding. When it is nearly too dark to see, the crepuscular nightjar may begin its churring display call, before hunting moths and other nocturnal flying insects over the heather.


From mid-July until autumn there is usually a pre-migration roost of stone-curlew on the heath. Breckland is the main UK breeding stronghold for this strange looking rare nocturnal bird. The stone-curlew is a crow-sized bird with a large head, long yellow legs and relatively long wings and tail. Active at night, its large yellow eyes enable it to locate food when it is dark. It is not related to curlews and gets its name from its curlew-like call. Numbers in the roost peak in September and in recent years there have been over 100 birds, usually viewable well from the main track through the reserve. Most have gone by the end of October, heading south to spend the winter around the Mediterranean, in southern Europe or North Africa.

Depending upon how dry the summer has been, there can be a good showing of fungi on the heath in autumn, with the most noticeable being the large parasol mushroom and the fly-agaric -the quintessential toadstool, the latter is a large white-gilled, white-spotted, usually deep red mushroom, one of the most recognizable and widely encountered in popular culture.


Conditions can be harsh on the heath, but there is a stark beauty, especially after a fall of snow. Flocks of siskins and redpoll can usually be found feeding in riverside alders and there is always the chance of something more unusual, like a hen harrier or great grey shrike.

Managing the reserve

Cavenham Heath, in common with other remaining fragments of Breckland heath, has been shaped by man's activity. From Neolithic woodland clearance through centuries of periodic small scale cultivation and grazing by sheep and rabbits, the distinctive sandy open landscape has been created and maintained.

Natural England uses grazing to manage much of the reserve. The site is registered organic with the Soil Association, and so only organic livestock can be used – hardy sheep on the heath and cattle on the river meadows. In addition the site has a large population of rabbits – the bane of farmers and gardeners, but here welcomed for the short grazed turf and disturbed ground that their activities produce-ideal conditions for the rare Breckland flora and fauna.

The delicate heathland flora thrives on nutrient poor, free-draining sandy soils. In recent decades Cavenham, in common with many heaths in north-west Europe, has become more grassy. It is thought that this is due in large part to the deposition of atmospheric nitrogen (from various man-made sources) onto the heath. This encourages more vigorous grasses to invade and out-compete the rarer plants. We are investigating ways to combat this problem, and have carried out small scale trials of turf and soil-stripping , in an effort to remove excessive nutrients.

A recent studyexternal link by the University of East Anglia has highlighted the importance of Breckland for its unique biodiversity. The audit also demonstrated the importance of bare and disturbed ground for many of its special flora and fauna. Grazing with sheep and cattle alone can produce a tight sward with little or no bare ground . Our regular rabbit counts on the heath have shown that, whilst there is still a good population, there is evidence of a decrease in the last few years and hence a decrease in the amount of disturbed ground. We are intending to cultivate selected areas of the heath periodically, using rotovator or a small plough, in order to ensure a continuous supply of bare or sparsely vegetated ground for our special species to thrive.

Much of the open heath is covered with heather , a lot of which is of a similar mature age and beginning to die back. We will be carrying out management to produce a diverse mosaic of heather of different age classes, intermingled with areas of bare ground, lichen heath and grasses.

Bracken is an invasive species that can be an issue on heathland. We try to check its spread by periodic mechanical cutting. In some years ragwort grows in profusion on the reserve. This species is a natural part of the heathland flora, and provides valuable nectar for a host of insects, including bees and butterflies. Unfortunately it is also poisonous to some livestock and so in years when it is particularly abundant we cut it to prevent it seeding.

The River Lark forms the northern boundary of the reserve and greatly enhances the wildlife interest. In the 1960s the river was embanked, effectively preventing the periodic natural flooding of the low lying river meadows. As a result, in recent decades the meadows have dried out and many wetland plants have declined or been lost. Natural England formulated a floodplain restoration feasibility plan, and a modified version of this was implemented by the Environment Agency in early 2010. Side weirs were cut in the river bank either side of the river at Temple Bridge, allowing floodwater to spill out onto the meadows at times of highest river flow. There have been a number of shallow floods since then, and eventually it is hoped that such events will restore these areas to their former glory.

Over the last 20 years we have removed several hectares of birch woodland to restore valuable open heath. This species readily invades open habitats in the absence of any control such as grazing – in the 1950s and 1960s an absence of sheep and the virtual disappearance of rabbits due to myxomatosis allowed birch to rapidly colonise the formerly open heath.

The remaining woodland on the reserve will be maintained and is managed on a limited intervention basis, allowing natural processes to occur. Much of it is still relatively young and dominated by the pioneering birch, but it is very much a habitat in transition. Seedlings of other tree species are beginning to appear, and very slowly in the coming decades birch will decline and the woods will transform into oak woodland.

How to get there

The reserve is one km south of the A1101 (between Bury St Edmunds and Mildenhall) near the village of Icklingham.

On foot

The reserve can be accessed from Icklingham on foot and is near the junction of two major trails, the Icknield Wayexternal link and St Edmund Wayexternal link.

By train

The nearest train stations are in Bury St Edmundsexternal link (12 km to the south east), Newmarketexternal link (15 km to the south west) and Thetfordexternal link (13 km to the north east).

For details of railway times and bus times, go to the Traveline websiteexternal link.

By car

Access to the reserve is via a minor road from Tuddenham village, two km to the south east. There is a car park on the Tuddenham to Icklingham road, adjacent to the reserve.

Visiting the reserve

Please note: Between March and October adders are found in this area, they are quite timid in nature and will not usually bite unless they feel threatened or cornered. Due to their inquisitive nature dogs can sometimes disturb adders whilst exploring undergrowth making them susceptible to being bitten. If your pet is bitten by an adder you should seek prompt veterinary attention.

Do not attempt first aid measures such as sucking out the venom or applying a tourniquet - these
procedures are ineffective and may even cause further harm to your pet. Try to keep your pet calm and wherever possible carry your dog rather than let it walk. Both these measures will help slow the spread of venom around the body. For best precaustion please keep dogs on a lead between March and October. Cavenham Heath is on Open Access land, which has some seasonal restrictions.

The nearest toilet and refreshment facilities are in local villages.

There are three nature trails through the reserve highlighting the heathland, woodland and wetland areas, briefly described below:

  • The 2.3 km woodland trail starts at the car park and has a one km easy-access section suitable for wheelchairs.
  • The 3.8 km heathland trail is also accessed via the car park and is reasonably accessible in dry weather.
  • The 1.3 km wetland trail is accessed via the heathland trail or public footpath.

Further information

Please contact the reserve by email or by calling Chippenham Fen NNR Office on 01638 721329