Sites - Herts & Middx Butterfly Conservation

Butterfly Sites in Hertfordshire & Middlesex

There are many places in Hertfordshire and Middlesex where you can see butterflies and some of these sites will be good for recording our common species.

However, throughout the two counties there are some very special places where the rarer butterfly species might be encountered. At some of these sites, it might require a lot of patience and the sighting might be only very brief but nevertheless we hope just as memorable.

The list includes most of the notable sites found throughout the branch area. We have included a grid reference and some of the species that might be seen and at which times of the year. We apologise in advance if any of the details are found to be incorrect.

More details of the sites can be found in the recently published (2016) Butterflies of Hertfordshire and Middlesex which can be purchased through the Herts Natural History Society.

Warning: Do not leave any valuables or items on display when parking cars in the more remote areas. Unfortunately many of these sites are targetted by thieves!


The Broxbourne and Wormley Woods Complexes cover a large area of woodland south of Hertford and west of Hoddesdon in Hertfordshire. There are several different woods and these have all been listed seperately. The central woodland area of Highfield, Brambles and Cowheath are private and have limited public footpath access. Box Wood north of Lord Lane is private with no public access although Elbow Lane (Ermine Street) runs parallel.

The two complexes are probably the best sites in Hertfordshire to see woodland butterflies and moths. There are several public carparks, although we recommend the West Carpark for Purple Emperor and White Admiral. Wormley Woods NR to the south of White Stubbs Lane, is recommended for White Admiral and Purple Emperor but receives fewer visitors.



Colour key:


Click on habitat type above for more on the associated sites


Site: Bedfont Country Lakes Park
Grid Reference and Postcode: TQ083727 - TW14 8BF
Access: Between Feltham and Ashford in the London Borough of Hounslow
Parking: At Clockhouse Lane and Bedfont Road entrances
Public Transport: Nearest station is Ashford on the South Western Railway
Key Species: Green Hairstreak and Purple Hairstreak
Best time to visit: May for Green Hairstreak
Further information: Variety of wet and dry habitats. Brown Hairstreak eggs found nearby, e.g. Raleigh Park Open Space so worth checking for this species on the wing in July, August and September
Additional Notes: Owned by the London Borough of Hounslow
Site: Bishop's Stortford Southern Country Park, Thorley, near Bishop's Stortford
Grid Reference and Postcode: TL474194 - CM23 4BH
Access: Several footpaths throughout the park
Parking: Car park on site
Public Transport: Nearest station is Bishop's Stortford from London Liverpool Street. Local bus service available from the station.
Key Species: All grassland species
Best time to visit: Throughout the season
Further information: This green space was created during the building of the St. Michael's Development and has quickly become a really good butterfly site.
Additional Notes: The site is owned by East Hertfordshire District Council
Site: Bunkers Park/Long Deans, near Hemel Hempstead
Grid Reference and Postcode: TL075047 - HP3 8BS
Access: Several footpaths
Parking: TL073078 - From the A4147 Hemel Hampstead to St Albans road turn right in Leverstock Green towards Bedmond. At the small crossroads turn right into Bunkers Lane. The reserve is situated about one kilometre along on the left. There is limited parking in Bunkers Lane and along Highwoodhall Lane which is on the left.
Public Transport: Nearest station is Apsley from London Euston. Local bus service available from Hemel Hempstead.
Key Species: All grassland species in particular Common Blue and Marbled White
Best time to visit: Throughout the season
Further information: Good walking shoes recommended
Additional Notes: This is a Herts & Middlesex Wildlife Trust Reserve
Site: Cheshunt Park, Flamstead End, Cheshunt
Grid Reference and Postcode: TL345045 - EN7 6QD
Access: Several footpaths throughout the park
Parking: TL347037 - good parking facilities
Public Transport: Nearest station is Cheshunt from London Liverpool Street. Regular bus service in the area
Key Species: All grassland species in particular Small Copper and Small Heath. White-letter Hairstreak are found on the elms by the clubhouse!
Best time to visit: Throughout the season
Further information: This is one of the best grassland sites in south east Hertfordshire.
Additional Notes: The site is managed by Broxbourne Borough Council. There is a cafe and there are publically accessible toilets in the golf clubhouse
Site: Cranford Country Park, The Parkway, Cranford
Grid Reference and Postcode: TQ101775 - TW5 9RZ
Access: Walks and trails through woodlands, wildflower meadows and wetlands that comprise of marshland, ditches and ponds
Parking: TQ101781 - carparking available
Public Transport: The closest underground stations are Hounslow West on the Piccadilly Line (approximately 2.5 km to the south east) from where bus services 81, 222 and H98 can be found or Hatton Cross which is also on the Piccadilly Line (approximately 2.5 km to the south west). The nearest railway station is Hayes and Harlington (approximately 1 km to the north west) which departs from Paddington in Central London. Bus services 195 and E6 can be found here.
Key Species: Grassland species including Small Copper and Common Blue
Best time to visit: Throughout the season
Further information: There is a visitor centre and toilets
Additional Notes: IP Ecology and Countryside Service manages the area along with Hounslow Heath Local Nature Reserve and Bedfont Lakes Country Park
Site: Croxley Common Moor
Grid Reference: TQ082948
Access: In Croxley Green via Mill Lane or from Moor Lane Crossing which lies just off Tolpits Lane
Parking: In Croxley Green
Public Transport: Nearest station is Croxley on the Metropolitan Line
Key Species: Marbled White
Best time to visit: Late June and July
Further information: Grassland across a floodplain
Additional Notes: Owned by the Three Rivers District Council
Site: Great Ashby Woodland and District Park, Great Ashby, Stevenage
Grid Reference: TL267267
Access: Several footpaths throughout the park
Parking: TL266269 limited parking spaces in a small carpark at the end of Serpentine Way, off Great Ashby Way. It's also possible to park on the main road, close to the entrance of Pryors Wood at approx. TL264264.
Public Transport: Nearest station is Stevenage from London Kings Cross. Local bus service available from Stevenage Town.
Key Species: All grassland species including Marbled White. Also White-letter Hairstreak are seen on adjacent elm
Best time to visit: Throughout the season
Further information: This space was redeveloped following the building of the Great Ashby Development and has quickly become a really good butterfly site.
Additional Notes: The site is next to Pryor's Wood which is a Herts & Middlesex Wildlife Reserve. The site is managed by North Hertfordshire District Council
Site: Heartwood Forest
Grid Reference: TL177110
Access: North-east of Sandridge, about 4 km north of St. Albans
Parking: Large car park at the Sandridge end
Public Transport: Nearest stations are Harpenden to the north-west and Welwyn Garden City to the east
Key Species: Small Blue and Marbled White
Best time to visit: May and June for Small Blue, and July for Marbled White
Further information: Grassland on the eastern side of the car park
Additional Notes: Owned by the Woodland Trust
Site: Hillbrow, Letchworth
Grid Reference: TL205315
Access: East of the Stotfold Road, south of Wilbury Hill, west Letchworth
Parking: At Wilbury Hill picnic site off Stotfold Road near the Icknield Way junction or street parking in Letchworth
Public Transport: Nearest stations are Hitchin to the south-west and Letchworth to the north-east
Key Species: Small Blue and Marbled White
Best time to visit: May and June for Small Blue, and July for Marbled White
Further information: Grassland on west-facing hill
Additional Notes:  
Site: Horsenden Hill
Grid Reference: TL160845
Access: Between Greenford and Perivale, south-west of Wembley
Parking: Car park on Horsenden Hill Lane North
Public Transport: Nearest stations are Sudbury Town on the Piccadilly Line, and Central Line at Greenford and Perivale
Key Species: White-letter Hairstreak and Brown Hairstreak
Best time to visit: July for White-letter Hairstreak. August and September for Brown Hairstreak
Further information: Grassland and hedgerows. Brown Hairstreaks should be searched for on blackthorn and tall trees nearby
Additional Notes: Owned by the London Borough of Ealing
Site: Hounslow Heath
Grid Reference: TQ125745
Access: Between Feltham and Hounslow in west Middlesex
Parking: At the northern edge
Public Transport: Nearest station is Hounslow
Key Species: Green Hairstreak
Best time to visit: May and June
Further information: Grassland and heathland st the southern end by the railway
Additional Notes: Owned by the London Borough of Hounslow
Site: Nomansland Common
Grid Reference: TL170124
Access: Open access
Parking: TL170124 - Nomansland Common is situated between the villages of Wheathampstead and Sandridge, approximately 2 miles north of St Albans, Hertfordshire. The Common is divided by the B561 St Albans Road, Ferrers Lane, Down Green Lane and Drovers Lane. Car parking is available on Ferrers Lane.
Public Transport: The nearest station is approximately 3 miles away at Harpenden from London St Pancras and there is a bus stop at the Wicked Lady Public House with a regular bus service operating between St Albans and Wheathampstead
Key Species: All grassland species especially Small Copper and Small Heath.
Best time to visit: Throughout the season
Further information: Nomansland Common is owned by the Althorp Estate and Wheathampstead Parish Council. It's managed by St Albans City & District Council under a Scheme of Management drawn up in 1953 and in consultation with the Joint Management Committee
Additional Notes:
Site: Patmore Heath, Albury, near Bishop's Stortford
Grid Reference: TL443258
Access: Open access
Parking: TL443258 - The reserve is 3km north of Little Hadham which is on the A120 between Bishop's Stortford and Standon. Upon reaching Gravesend, a lane on the right leads east to the reserve. Parking bays alongside the common.
Public Transport: Very limited, nearest station is Bishop's Stortford
Key Species: All grassland species in particular Small Copper and Small Heath.
Best time to visit: Throughout the season
Further information: This SSSI is an outstanding example of grass heathland. With its ponds, the reserve is rich in flora and insects. Strong shoes recommended.
Additional Notes: This is a Herts & Middlesex Wildlife Trust Reserve
Site: Six Hills Common, Stevenage
Grid Reference: TL237237
Access: South-west of Stevenage Town Centre opposite police station
Parking: Car park at the ASDA superstore
Public Transport: Nearest station is Stevenage
Key Species: White-letter Hairstreak
Best time to visit: Late June and July
Further information: Grassland heavily grazed by rabbits, with cluster of mature elms on the western side
Additional Notes: Owned by Stevenage Borough Council
Site: Totteridge Fields
Grid Reference: TQ223940
Access: In the angle between Hendon Wood Lane and Totteridge Common
Parking: No car park
Public Transport: Nearest stations are Mill Hill Broadway to the south-west and Totteridge and Whetstone to the east on the Northern Line
Key Species: Marbled White and Purple Hairstreak
Best time to visit: Late June and July
Further information: Grassland and hedgerows
Additional Notes: Owned by the London Wildlife Trust



Site: Balls Wood and Hertford Heath, near Hertford
Grid Reference: TL343106 (Balls Wood)
Access: Several footpaths
Parking: TL348103 (for Balls Wood and Hertford Heath west) Park on the Roundings next to the College Arms pub
Public Transport: Nearest stations are Hertford East from London Liverpool Street or Hertford North from London Kings Cross. Regular bus service between Broxbourne Station and Hertford passes through Hertford Heath
Key Species: White Admiral, Silver-washed Fritillary, Purple Hairstreak and the occasional Purple Emperor. Good for all woodland butterflies!
Best time to visit: Throughout the season
Further information: This is one of the best woodland sites for White Admiral.
Additional Notes: This is a Herts & Middlesex Wildlife Trust Reserve
Site: Bencroft Wood NR, near Broxbourne
Grid Reference: TL328063
Access: Several footpaths and trails
Parking: TL331064 (Bencroft Wood West off White Stubbs Lane)
TL326064 (Bencroft Wood East off White Stubbs Lane)
Public Transport: Nearest stations are Broxbourne from London Liverpool Street or Bayford from London Moorgate
Key Species: White Admiral and Silver-washed Fritillary
Best time to visit: Late June and July
Further information: Part of the Broxbourne Woods complex
Additional Notes: Owned by Hertfordshire County Council
Site: Bramfield Park Wood
Grid Reference: TL285154
Access: West of Bramfield village down the bridleway called Bury Lane
Parking: In the village
Public Transport: Nearest station is Watton-at Stone
Key Species: White Admiral and Silver-washed Fritillary
Best time to visit: Late June and July
Further information: The best place of the wood is the bridleway in the north-western part
Additional Notes: Owned by the Woodhall Park Estate
Site: Bricket Wood Common, near Watford
Grid Reference: TL131010
Access: Several footpaths and tracks
Parking: TL132006, lay by near clearing along School Lane, Bricket Wood
Public Transport: Nearest station is Bricket Wood Station from Watford Jnct to St. Albans Abbey Station. Turn right out of the station and head south along Station Rd. After a few hundred yards, the road bends round to the right. At the bend & just before the railway bridge take a left turn into School Lane. The lane winds through the wood and after half a mile or so you'll come to the meeting point at a parking bay on the left of the lane, with a large clearing on the right.
Key Species: Silver-washed Fritillary, Purple Emperor, White Admiral, Purple Hairstreak also Marbled White and Brimstone. Good for all woodland butterflies! Purple Emperors are also present but elusive.
Best time to visit: Throughout the season but late June and July for Silver-washed Fritillary, Purple Emperor and White Admiral
Further information:
Additional Notes: This has become one of the best sites in Hertfordshire to observe woodland butterflies. Managed by St Albans City and District Council
Site: Broxbourne Wood NR (part NNR, SSSI), near Hertford
Grid Reference: TL325072
Access: Several footpaths and walks including an easy access woodland trail
Parking: TL324070 (West Carpark off Pembridge Lane) - recommended for Purple Emperor
TL327069 (East Carpark off Pembridge Lane)
Public Transport: Nearest station is Bayford from London Moorgate. There is a limited bus service to Brickendon Green from Hertford.
Key Species: Purple Emperor, White Admiral, Purple Hairstreak and occasional Silver-washed Fritillary
Best time to visit: Late June and July for Silver-washed Fritillary, Purple Emperor and White Admiral
Further information: Part of the Broxbourne Woods complex, this site was probably one of the best sites in Hertfordshire to see woodland butterflies, throughout the season. However, recent management has not been favourable to butterflies. We ask that observers still visit though and report back their sightings.
Additional Notes: Owned by Hertfordshire County Council
Site: Danemead part of the NNR SSSI, near Hoddesdon
Grid Reference and Postcode: TL346078 - EN11 8GG
Access: Open access with adjacent footpaths
Parking: TL347087 (Goose Green off Lord Street) or TL346077 (Ermine Street off Cock Lane)
Public Transport: Nearest station is Broxbourne from London Liverpool Street
Key Species: White Admiral, Purple Emperor and Silver-washed Fritillary
Best time to visit: Late June and July
Further information: Sheep may be present on the site, please keep dogs on a lead.
Additional Notes: This is a Herts & Middlesex Wildlife Trust Reserve
Site: Heartwood Forest
Grid Reference: TL162114
Access: North-east of Sandridge, about 4 km north of St. Albans
Parking: Large car park at the Sandridge end
Public Transport: Nearest stations are Harpenden to the north-west and Welwyn Garden City to the east
Key Species: Purple and White-letter Hairstreaks
Best time to visit: Late June and July
Further information: Woodland is on the western side of the car park
Additional Notes: Owned by the Woodland Trust
Site: Hoddesdon Park Wood NNR SSSI, near Hoddesdon
Grid Reference: TL351084
Access: Several footpaths and trails
Parking: TL347087 (Goose Green off Lord Street) or TL346077 (Ermine Street off Cock Lane)
Public Transport: Nearest station is Broxbourne from London Liverpool Street
Key Species: White Admiral
Best time to visit: Late June and July
Further information: The site is very good for woodland flowers in the spring
Additional Notes: This is a Woodland Trust Reserve
Site: Northaw Great Wood SSSI, near Cuffley
Grid Reference and Postcode: TL280038 - EN6 4BG
Access: Several footpaths and trails
Parking: TL282040 (off the Ridgeway) Carpark and toilets - small charge payable for parking.
Public Transport: Nearest station is Cuffley from London Kings Cross. Regular bus service to Cuffley
Key Species: White Admiral, Purple Hairstreak and Silver-washed Fritillary. Good for all woodland butterflies! There is Purple Emperor territory close to the carpark but there have been few reports of groundings
Best time to visit: Throughout the season
Further information: This is a good woodland site for White Admiral and Silver-washed Fritillary. There are toilets next to the carpark
Additional Notes: The site is managed by Welwyn and Hatfield Council
Site: Norton Green Common, near Stevenage
Grid Reference: TL228227
Access: Accessed by byways south of North Green, there are several footpaths and tracks
Parking: Norton Green TL229233
Public Transport: Nearest railway station is Stevenage which is just over 2 km to the east.
Key Species: The area is good for many species including some specialist woodland butterflies!
Best time to visit: Throughout the season but late June and July for Purple Emperor, Silver-washed Fritillary and White Admiral
Further information:
Additional Notes: The woodland is privately owned so please keep to the public footpaths
Site: Ruislip Woods NNR SSSI, Ruislip
Grid Reference: TQ083899
Access: Several footpaths and tracks
Parking: Various locations including:
TQ086891 (Ruislip Lido)
Mad Bess Wood (TQ079896)
St Vincent's Hospital (TQ095897)
Public Transport: Nearest tube station is Northwood Hills, 2 km to the east, served by the Metropolitan Line of the London Underground. The nearest railway station is West Ruislip which is 2 km to the south.
Key Species: Purple Emperor, White Admiral and Purple Hairstreak. Good for all woodland butterflies!
Best time to visit: Throughout the season but late June and July for Purple Emperor and White Admiral
Further information: Ruislip Woods consists of Bayhurst Wood, Copse Wood, Mad Bess Wood, Park Wood, Poor's Field, Grub Ground. It is the biggest single area of woodland in Greater London. There are toilet and refreshment facilities at Ruislip Lido
Additional Notes: Ruislip Woods is owned and managed by the London Borough of Hillingdon
Site: Symondhyde Great Wood, near Welwyn Garden City
Grid Reference: TL199107
Access: Between Hatfield and Sandridge, north of Coopers Green Lane
Parking: Small car park at the site
Public Transport: Nearest stations are Hatfield to the south-east and Welwyn Garden City to the north-east
Key Species: Purple Hairstreak, Silver-washed Fritillary and White Admiral
Best time to visit: Late June and July
Further information: Mixed woodland. Best part is power line wayleave north of the bridleway
Additional Notes: Owned by Gascoyne Cecil Estates
Site: Whippendell Woods, near Watford
Grid Reference: TQ076978
Access: West of Watford, beyond Cassiobury Park
Parking: Several car parks on the perimeter
Public Transport: Nearest stations are Watford to the east and Croxley on the Metropolitan Line to the south
Key Species: Purple Emperor, Purple Hairstreak, Silver-washed Fritillary, White Admiral and White-letter Hairstreak
Best time to visit: Late June and July
Further information: Ancient woodland with wide rides and glades
Additional Notes: Owned by Watford Borough Council
Site: Wormley Wood NNR SSSI, near Broxbourne
Grid Reference: TL318058
Access: Several footpaths and trails
Parking: TL331064 (Bencroft Wood West off White Stubbs Lane)
TL318066 (limited access)
TL315046 (footpath access with restricted parking from Hammond Street, gate is locked at night)- good for the south side of the wood
Public Transport: Nearest stations are Broxbourne from London Liverpool Street. Regular bus service from Waltham Cross to Cheshunt, Hammond Street
Key Species: Purple Emperor, White Admiral, Purple Hairstreak and occasional Silver-washed Fritillary. Good for all woodland butterflies!
Best time to visit: Late June and July
Further information: Part of the Broxbourne Woods complex but rarely visited by butterfly watchers. This a wood of two halves - the northern section is relatively high canopy mature woodland but the southern section, is much younger and rich in sallow and honeysuckle and as a result it is a very important site for Purple Emperor and White Admiral.
Additional Notes: This is a Woodland Trust Reserve



Site: Chorleywood Common, near Rickmansworth
Grid Reference: TQ031962
Access: Just outside the M25 (junction 18) and south of the A404
Parking: Car parks at the site
Public Transport: Nearest stations are Rickmansworth to the south-east and Croxley on the Metropolitan Line to the east
Key Species: Marbled White and Purple Hairstreak
Best time to visit: Late June and July
Further information: Acid, neutral and chalk grassland plus woodland
Additional Notes: Owned by the Chorleywood Parish Council
Site: Ellenbrook Fields, near Hatfield
Grid Reference: TL207086
Access: West of Hatfield Business Park and the University of Hertfordshire de Havilland Campus
Parking: Car park at Notcutts Garden Centre near the south-western corner off Hatfield Road
Public Transport: Nearest station is Hatfield
Key Species: Marbled White, Purple Hairstreak and Silver-washed Fritillary
Best time to visit: Late June and July
Further information: Permissive paths on the site containing grassland and woodland at the northern end
Additional Notes: Owned by Goodman UK Business Parks
Site: Hampstead Heath
Grid Reference: TQ263873
Access: North of Hampstead, 6km north of central London
Parking: Very limited
Public Transport: Nearest station is Hampstead Heath
Key Species: Marbled White, Purple Hairstreak, White Admiral and possible Purple Emperor
Best time to visit: Late June and July
Further information: A mixture of deciduous woodland and grassland attracting a high number of species
Additional Notes: Owned by the City of London Corporation
Site: Mardley Heath Nature Reserve
Grid Reference: TL248183
Access: East of the A1(M) west of Woolmer Green
Parking: On Heath Road
Public Transport: Nearest station is Knebworth
Key Species: Marbled White, Purple Hairstreak and Silver-washed Fritillary
Best time to visit: Late June and July
Further information: Acid grassland and secondary woodland
Additional Notes: Owned by the Welwyn-Hatfield Council
Site: Merry Hill, near Bushey
Grid Reference: TQ130940
Access: Between Bushey and Carpenders Park
Parking: No parking on Merry Hill Road
Public Transport: Nearest station is Bushey
Key Species: Marbled White and Purple Hairstreak
Best time to visit: Late June and July
Further information: Grassland and young woodland on the edges
Additional Notes: Owned by the Woodland Trust
Site: Monken Hadley Common
Grid Reference: TQ252974
Access: Between Monken Hadley in the west and Cockfosters in the east
Parking: Car park at end of Bakers Hill, just west of railway
Public Transport: Nearest station is Hadley Wood
Key Species: Marbled White and Purple Hairstreak
Best time to visit: Late June and July
Further information: Grassland and woodland. Includes the Covert Way Nature Reserve just east of the railway containing dense woodland but with a large clearing
Additional Notes: Common land vested in the Monken Hadley Common Trustees and the London Borough of Enfield
Site: Oak Hill Park
Grid Reference: TQ280945
Access: Between east Barnet and Southgate
Parking: Car park off Parkside Gardens near the golf course
Public Transport: Nearest stations are Oakleigh Park to the west, and Oakwood and Southgate to the east on the Piccadilly Line
Key Species: Marbled White and Purple and White-letter Hairstreaks
Best time to visit: Late June and July
Further information: Deciduous woodland plus some grassland
Additional Notes: Owned by the London Borough of Barnet
Site: Panshanger Park
Grid Reference: TL306125
Access: Between Welwyn Garden City and Hertford
Parking: On Thieves Lane, Hertford
Public Transport: Nearest station is Hertford North
Key Species: Marbled White, Purple Hairstreak and possible Purple Emperor
Best time to visit: Late June and July
Further information: A mix of deciduous woodland, arable farmland, mixed and wetlands
Additional Notes: Owned by Tarmac Ltd., managed in partnership with the Herts & Middlesex Wildlife Trust
Site: Pishiobury Park, near Sawbridgeworth
Grid Reference: TL478139
Access: South of Sawbridgeworth from Newton Drive
Parking: Car park off A1184 (Harlow Road)
Public Transport: Nearest station is Harlow Mill
Key Species: Marbled White
Best time to visit: Late June and July
Further information: A variety of grassland, wetland and woodland habitats in a parkland landscape
Additional Notes: Owned by the East Hertfordshire District Council
Site: Stanmore Country Park
Grid Reference: TQ173927
Access: North of Stanmore
Parking: Car park at the main entrance off Dennis Lane
Public Transport: Nearest station is Stanmore
Key Species: Marbled White, Silver-washed Fritillary, Purple and White-letter Hairstreaks
Best time to visit: Late June and July
Further information: Acid grassland and mature woodland
Additional Notes: Owned by the London Borough of Harrow
Site: Stanwell Moor, near Heathrow
Grid Reference: TQ042749
Access: Open land to the west of Heathrow Airport
Parking: No car park
Public Transport: Nearest station is Wraysbury
Key Species: Purple Hairstreak
Best time to visit: Late June and July
Further information: Secondary woodland and rough grassland
Additional Notes: Owned by various organisations
Site: Trent Park, Enfield
Grid Reference: TQ282970
Access: Northern edge of Enfield Borough
Parking: Inside the park by the cafe
Public Transport: Nearest stations are Cockfosters and Oakwood, both on the Piccadilly Line
Key Species: Marbled White, Purple and White-letter Hairstreaks
Best time to visit: Late June and July
Further information: Mix of woodland, arable farmland and grassland
Additional Notes: Owned by the London Borough of Enfield



Site: Aldbury Nowers, near Tring
Grid Reference: SP951129 (SP950137 Upper compartment)
Access:Several footpaths
Parking: SP949128 - layby on Northfield Road (turn left just north of Tring Station). Space is limited, but there is additional parking at Tring Station about 600m away. Warning: there have been reports of car thiefs from the layby in 2007
Public Transport: Nearest station is Tring (London Euston to Tring).
Key Species: All chalk species but in particular Grizzled Skipper, Dingy Skipper and Green Hairstreak. Large numbers of Brimstone butterflies. Small Blue are now confirmed to be breeding on the site. Dark Green Fritillary are now being seen on regular occasions in the summer.
Best time to visit: All season but late April and May for Small Blue, Grizzled Skipper, Dingy Skipper and Green Hairstreak. Also Chalkhill Blue and Dark-green Fritillary
Further information: This is a site of two halves. Walk across the field from the layby to the immediate grassland slopes. These compartments are good for all species although Grizzled Skipper are rarely encountered. Walk through the site and take the Ridgeway path towards Pitstone Hill, the furthest compartment is some distance up the steep path just before the path opens onto Pitstone Hill. The slopes here are very steep and great care must be taken. All species are present in this compartment including Grizzled Skipper although they can be elusive. They are most likely to be encountered at the bottom of the escarpment around a large bramble bank.
Additional Notes: This is a Herts & Middlesex Wildlife Trust site and has recently been subject to major habitat restoration. There are some very steep slopes and strong shoes are recommended
Site: Hexton Chalk Pit, near Hitchin
Grid Reference: TL106299
Access:Several footpaths in the area
Parking: It is possible to park on the road close to the entrance at approx TL106301. Alternatively park in the village of Hexton but take great care walking along the road.
Public Transport: A bus service from Hitchin passes through Hexton
Key Species: Dingy Skipper and Chalkhill Blue. Also occasional Green Hairstreak. Dark-green Fritillary are now being seen on regular occasions in the summer.
Best time to visit: All season but late April and May for Dingy Skipper and July and early August for Chalkhill Blue. Look out for Dark Green Fritillary.
Further information: This is one of the best sites in Hertfordshire for Dingy Skipper and Chalkhill Blue. In some years there are very large numbers of Chalk-hill Blue
Additional Notes: This is a Herts & Middlesex Wildlife Trust Reserve. The site is close to the Pegsdon Hills (Bedfordshire) and could form part of a longer visit to the area.
Site: Roughdown Common, near Hemel Hempstead
Grid Reference: TL026055
Access: West of Hemel Hempstead (Box Moor Trust Centre)
Parking: Small car park at Westbrook Hay
Public Transport: Nearest station is Hemel Hempstead
Key Species: Green Hairstreak
Best time to visit: Late April and May
Further information: Chalk grassland. Small Blue colonies just a few metres on the northern side of the A41 at Bourne End
Additional Notes: Owned by the Boxmoor Trust
Site: Therfield Heath, Royston
Grid Reference: TL343402
Access:Several footpaths across the Heath
Parking: TL347406 Sports Pavillion Carpark or TL336402 off the Baldock Road, towards Therfield
Public Transport: Nearest station is Royston (London Kings Cross to Cambridge).
Key Species: All chalk grassland species - in particular Chalkhill Blue and recently Dark Green Fritillary.
Best time to visit: All season but July and early August for Chalkhill Blue
Further information: The site covers a large area and butterflies will be encountered throughout. Pasque Flowers can be found in the spring.
Additional Notes: The site is managed by the Therfield Heath Conservators. Fox Covert is a Herts & Middlesex Wildlife Trust Reserve
Site: Tring Park, near Tring
Grid Reference: SP930104
Access:Several footpaths
Parking: There are several options. Park in Tring and walk across the Park from SP925110 (by the Natural History Museum). Alternatively off Hastoe Lane at approx SP923101 or Hastoe Cross Roads at SP923094 (walk along road to wood entrance but care must be taken walking along the road). It is also possible to enter from the Wiggington side at approx SP934105.
Public Transport: Nearest station is Tring from London Euston.
Key Species: Chalk species. Also Silver-washed Fritillary and Purple Emperor
Best time to visit: All season but April and May for Green Hairstreak. July for Purple Emperor and Silver-washed Fritillary
Further information: This is a large site and has been one of the best in Hertfordshire for all species. The escarpment slopes are very steep and great care must be taken. The Purple Emperor can be elusive. No Grizzled Skipper have been recorded for some years.
Additional Notes: This is a Woodland Trust Reserve.
Site: Weston Hills, near Baldock
Grid Reference: TL246324
Access: East of Baldock, west of the A505 bypass
Parking: Car park at the southern end on Hatch Lane
Public Transport: Nearest station is Baldock
Key Species: Marbled White and possible Dark Green Fritillary
Best time to visit: Late June and July
Further information: Chalk grassland with some woodland
Additional Notes: Owned by North Hertfordshire District Council



Site: Alexandra Park
Grid Reference and Postcode: TQ300902 - N22 7AY
Access:Several walks and trails
Parking: Several carparks on site
Public Transport: Nearest station is Alexandra Palace
Key Species: Urban butterflies including Holly Blue, Purple Hairstreak and White-letter Hairstreak
Best time to visit: Throughout the season
Further information: A good site for urban arboreal and grassland species
Additional Notes: The site is owned by the Alexandra Park and Palace Charitable Trust
Site: Bushy Park
Grid Reference and Postcode: TQ155965 - TW12 2EJ
Access: North of the River Thames surrounded by Hampton, Teddington and Hampton Court
Parking: In the park near the Diana Fountain
Public Transport: Nearest stations are Hampton to the west, Hampton Court to the south and Teddington to the north
Key Species: Small Copper, Small Heath, Purple Hairstreak and possible Brown Hairstreak
Best time to visit: July and August
Further information: Acid grassland and small areas of woodland. Brown Hairstreak eggs found at nearby Hampton Court Green
Additional Notes: Owned by the Royal Parks
Site: Fryent Country Park
Grid Reference and Postcode: TQ195877 - NW9 9SG
Access: Between Kingsbury and Wembley in north-west London
Parking: On Fryent Way near Barn Hill
Public Transport: Nearest stations are Kingsbury to the north and Wembley Park to the south
Key Species: Marbled White and Small Copper
Best time to visit: Late June and July
Further information: Mix of meadows and hedgerows
Additional Notes: Owned by the London Borough of Brent
Site: Kensal Green Cemetery
Grid Reference and Postcode: TQ230825 - W10 4RA
Access: Between the Grand Union Canal and Harrow Road, south of Kensal Green
Parking: Car park on site
Public Transport: Nearest station is Kensal Green on the Bakerloo Line and Overground
Key Species: Purple Hairstreak
Best time to visit: Throughout the summer
Further information: Flower-rich grassland and mature trees
Additional Notes: Owned by the General Cemetery Company
Site: Mudchute LNR, Isle of Dogs
Grid Reference: TQ382787
Access:Entrance gate to Reserve is on the opposite side of the road from the exit of Mudchute Station. Several walks and trails
Parking: Details not known but if coming by car follow sign for A1206 Isle of Dogs
Public Transport: Nearest station is Mudchute (Docklands LR). Bus routes: D6, D7, D8 or any service to Asda Isle of Dogs.
Key Species: Urban butterflies
Best time to visit: Throughout the season
Further information: Despite its urban location 17 species of butterfly have been recorded
Additional Notes: The site is managed by the Mudchute Association
Site: Tower Hamlets Cemetary LNR, Tower Hamlets
Grid Reference and Postcode: TQ367822 - E3 4PX
Access:The main gate is situated in Southern Grove. Several walks and trails, main gates are unlocked at 8:00am and locked again at dusk/9:00pm. Kissing gates remain open at all times
Parking: Details not known
Public Transport: Nearest station is Mile End (Central, District and Hammersmith & City Line Underground). Bus routes are: D6, D7, 25, 277 and 339.
Key Species: Urban butterflies including Holly Blue
Best time to visit: Throughout the season
Further information: An excellent urban site for butterflies - Silver-washed Fritillary made an appearance in 2006!
Additional Notes:



Site: Bovingdon Brick Pits
Grid Reference: TL004028
Access: West of Bovingdon in west Hertfordshire
Parking: Limited parking in Bovingdon
Public Transport: Nearest stations are Chesham to the west and Hemel Hempstead to the east
Key Species: Dingy Skipper, Marbled White and Silver-washed Fritillary
Best time to visit: May for Dingy Skipper. Late June and July for Marbled White and Silver-washed Fritillary
Further information: Disused brick pits
Additional Notes: Owned by the Boxmoor Trust
Site: Waterford Heath LNR, north of Hertford
Grid Reference: TL317149
Access:Several footpaths
Parking: TL317149 (off Vicarage Lane) for North and South Pit
TL320145 (off Sacombe Road) for the South Pit
Public Transport: Nearest station is Hertford North from London Kings Cross. A Monday to Saturday bus service from Hertford to Stevenage stops in the village of Waterford
Key Species: Grizzled Skipper
Best time to visit: April and May for Grizzled Skipper
Further information: This is probably the best site in Hertfordshire for Grizzled Skipper. The key areas are the plateau on the north pit near the railway line and the steep escarpment on the Sacombe Road side of the south pit.
Additional Notes: This is a Herts & Middlesex Wildlife Trust Reserve. Strong shoes are recommended