Natural England - Castor Hanglands NNR

Castor Hanglands NNR

Castor Hanglands contains a remarkable variety of plant and animal life. The Reserve has four distinct habitats – woodland, grassland, wetland and scrub, each of which has its own special wildlife.

Castor Hanglands NNR

Where: Cambridgeshire

Main habitats: Woodland, limestone grassland, scrub

Why visit: Covering an area of less than 90 hectares, Castor Hanglands is an oasis of green in an intensively farmed landscape. Walk amongst its ancient woodlands with their mediaeval boundary banks, the flowery heaths and commons still showing their 700 year old cultivation ridges, and ponds lying in marshy orchid-filled meadows, and you are stepping back in time to a world now almost gone. Within this special place Over 450 kinds of wild plant have been found, as well as many different birds, mammals and insects.

Star species: Amongst the rare plants found here are crested cow-wheat, lesser water-plantain, man orchid and narrow-leaved water dropwort. Toothwort, narrow-leaved everlasting pea, pyramidal orchid and greater butterfly orchid also occur. Woodland butterflies present include silver-washed fritillary, purple hairstreak and white admiral. The rare black hairstreak butterfly is best seen around the blackthorn scrub in June. The wetter parts of the site are covered with hundreds of common spotted and marsh orchids at this time of year. A large number of other rare insects have been recorded, many of them living in dead and decaying wood. Old coppice stools, with their gnarled bases, rot-holes and fallen limbs, are especially good for these insects and also for fungi, mosses and lichens.

Dense thickets of scrub provide shelter and nesting habitat for many summer migrant birds: nightingale, garden warbler, grasshopper warbler and turtle dove all breed regularly. In the woodland, all three British woodpeckers occur along with woodcock and the elusive hawfinch. Grass snakes are often seen by the ponds and harvest mouse occurs in the rough grassland on the heath.

Managing the reserve


For centuries the open grassland on Ailsworth Heath was grazed by sheep and cattle. This traditional management allowed many grasses and wild flowers to survive.. Common grazing ended by the 1930’s and today’s management seeks to maintain the grassland by grazing with horses, sheep and cattle in the traditional way.


Ancient woodlands such as Castor Hanglands are especially rich in plants and animals. Small areas of the woodland are still managed by traditional coppicing, cutting the trees on a rotational basis every 20-30 years. The remaining woodland is left to develop naturally. Deer are numerous in the area, including fallow and the smaller muntjac. Deer numbers are managed as too many deer can cause damage to the woodland, killing saplings and shrubs and reducing the number of bluebells and other woodland flowers.


Scrub is a mixture of shrubs and bushes such as hawthorn, blackthorn, wild privet, spindle, dogwood and wild rose. Many of the patches of scrub grew up on Ailsworth Heath after common grazing ended in the 1930’s.

Patches of scrub are cut back regularly to encourage the younger bushy growth that provides the right conditions for its unique wildlife.

Ponds and wetlands

In parts of the reserve, the water table lies just below ground level, making the land boggy and waterlogged for much of the year. There are also a number of ponds throughout the reserve which support many aquatic plants and animals. Eighteen species of dragonfly have been recorded as well as all three species of British newt. Frogs, toads and grass snakes are also seen regularly. . We carry out annual plant and butterfly monitoring programmes which help to asses the condition of the site.

Seasonal highlights

Spring The coming of spring is heralded in mid March, when about 2,000 toads gather at the main pond to breed – a sight not to be missed! Toothwort, a rare parasitic plant, also appears at this time. A little later the woodland floor has a mixture of plants including bluebell, primrose, violet, wood anemone and yellow archangel. This is also a great time to visit the scrub, where the song of the nightingale is sure to be heard alongside many other summer migrants including blackcap, willow warbler, garden warbler, whitethroat, cuckoo and turtle dove. In the grassland you will see patches of violets and cowslips flowering, with marsh marigold in the wetter areas.

Summer A profusion of wild flowers such as bird’s foot trefoil, rock-rose, harebell, ox-eye daisy and hay rattle may be seen on the drier soils on limestone. Wetter ground near the ponds is home to hundreds of common spotted and early marsh orchids, water mint, meadowsweet and fleabane. Butterflies such as common blue, meadow brown and brown argus can be seen in summer feeding on the wild flowers. A range of typical woodland birds are found in the woodland including nuthatch, treecreeper, tawny owl and woodcock.

Autumn Sees the arrival of cattle and sheep hardy sheep that play a vital part maintaining a flourishing population of wild flowers by grazing down the vegetation and woody shoots that would otherwise take over. In the scrub, the migrant birds have left but the scrub now provides a range of fruits and berries – sloes, blackberries, rose, hawthorn, privet, dogwood and elder -which are a valuable food source for birds and insects. This is a good time to search for fungi within the woodland.

Winter This is a quiet time within the grassland – you may see green woodpeckers scavenging for food amongst the many anthills, and this is the best time to look for signs of deer.


Events are held periodically at the site, these include a nightingale walk in spring. These are advertised on the BBC Things To Do websiteexternal link.

History and culture

The history of the area goes back over 2,000 years. The Western boundary of the Reserve follows King Street, a Roman Road connecting Castor and Bourne. Castor Hanglands wood is thought to have been woodland for over 1,000 years: the woodland in Castor is mentioned in the Domesday Book (1087), and the name ‘hangra’ is Old English for a wood on a hill. The woods later became part of the Mediaeval hunting Forest of Nassaburgh.

The grassland, scrub and wetland areas of the reserve are part of Ailsworth Heath. This land was ploughed around 800 years ago, leaving distinct ridges and furrows which can still be seen today. In about 1350, cultivation was abandoned, and the Heath became common land, grazed by sheep, cattle and ponies belonging to commoners in the village of Ailsworth. The Heath was later celebrated in the writings of Helpston’s ‘peasant poet’, John Clare, (1793-1864) who was the first person to record many of the plants, birds and other wildlife found there. During the late nineteenth Century the area became well known to entomologists looking for the black hairstreak and other rare butterflies. Part of the woodland was cleared and replaced by conifer trees in the early 1950s and in 1953 the remaining areas of woodland and heath were declared as one of Britain’s first National Nature Reserves, to preserve this unique part of our natural heritage.

How to get there

Castor Hanglands is situated 2 miles North of the village of Ailsworth village, 4 miles West of Peterborough in Cambridgeshire.

By cycle/on foot 

A Public Bridleway runs North-South through the length of the Reserve, and another crosses east-west, connecting with the parking area at Southey Wood. Horse riding and cycling are permitted only on the bridleways

By bus

Busesexternal link from Peterborough and Stamford stop hourly in Ailsworth (30 minutes walk).

By train

The nearest train station is Peterboroughexternal link (4 miles).

By car

The nearest parking available is in the Forestry Commission site at Southey Wood, on the Wansford-Bourne road, from which there is a 500m walk to the reserve.

Vising the reserve

Safety advice: paths may be muddy and uneven. The nature of the ground means that it is not suitable for wheelchair access.

Facilities: there are no facilities available on site, toilets and refreshments are available during normal business hours at the farm shop one mile north of the Reserve. These is also a shop, and public houses in Ailsworth, two miles to the south.

Dogs: Dogs are permitted on a lead or under close control, and must be on a lead when grazing stock are present.

There are two waymarked walks, the Heath Walk and Hanglands walk, which will take you around the main features of the Reserve, each lasting about one hour. The Heath walk takes you through the historic landscape of Ailsworth Heath, while the Hanglands walk concentrates on the ancient woodland areas.

School and community groups

Guided walks are offered to community groups, and activity visits can also be arranged for schools – these are most suitable for Key Stage 3 & 4. The reserve provides good opportunities for A level and Undergraduate studies looking at vegetation transects across different habitats. For bookings and further information, contact Chris Gardiner (Senior Reserve Manager) on 01780 444704, or email.

Want to get involved?

We are always looking for people to help us in our work – for example patrolling, site management, plant recording, or help with events, there is something for everyone. On Mondays and Wednesdays our weekday volunteers help with habitat restoration or maintenance work such as fencing, scrub clearance, or coppicing, that takes place on Castor Hanglands and other local Reserves.


For more information about visiting the reserve, contact Chris Gardiner (Senior Reserve Manager) on 01780 444704, or email.