Butterfly Spotting

PUBLISHED: 15:30 04 June 2008 | UPDATED: 15:13 20 February 2013

A brown argus

A brown argus

Helen Taylor from the local Wildlife Trust goes butterfly spotting in the chalk grasslands of the Chilterns and Berkshire Downs...

Helen Taylor from the local Wildlife Trust goes butterfly spotting in the chalk grasslands of the Chilterns and Berkshire Downs

It's surely one of nature's miracles that a stumpy caterpillar can fatten itself up, change into a dull chrysalis, but emerge as a beautiful and delicate butterfly. It seems the most unlikely transformation, but this is what is happening across Berkshire and the Chilterns throughout our summertime.

To find out more about BBOWT nature reserves, volunteering and events please visit www.bbowt.org.uk or call 01865 775476.

Butterflies can be found almost everywhere, but in Berkshire and the Chilterns we are blessed with one of the best habitats for summer butterfly-spotting - rare chalk grasslands. Once stretching across the Chilterns and Berkshire Downs, much of our chalk grassland has now been lost to encroaching scrub and arable crops, but thanks to the hard work of conservation groups like the Berks, Bucks & Oxon Wildlife Trust (BBOWT), places do exist where you can step back in time and enjoy a superb display of wildlife.

Rich in calcium from the underlying chalky soil and rock, this rare type of grassland supports a wide variety of wild flowers, with the summer pageant of orchids being a draw for many visitors. But it's not just humans that enjoy the delights of these seasonal blooms - butterflies and moths are attracted to these rich grassy slopes too.

Above: A small blue

Chasing butterflies in the Chilterns

For a fine day out, enjoy the magnificent views of the River Thames and sloping chalk grasslands of BBOWT's Hartslock Nature Reserve near Goring, famed for its orchids.

Butterflies that might be seen here include the chalkhill blue, green hairstreak, grizzled skipper and rare Adonis blue - catching the bright flash of the turquoise-blue male is a real treat.

Above: A marsh fritillary

To visit the reserve, park in Goring village and walk along the Thames Path for about one and a half miles to the entrance of the reserve. Here steep footpaths and steps will lead you on to the south-facing chalk downland where you can hunt for butterflies or simply relax and enjoy the stunning views. It can really feel as if you've stepped back in time to an ancient landscape.

If you want to enjoy more of the surrounding countryside, why not contact BBOWT's Wildlife Information Service on 01865 788307 or wildinfo@bbowt.org.uk for a WildWalk leaflet - a longer walk that takes in Hartslock and Goring.

Below: A green hairstreak.
Gavin Hageman

Another fantastic site for butterflies is BBOWT's Buttler's Hangings Nature Reserve near High Wycombe. This bank of chalk grassland is a summer suntrap for a rich variety of flowers and insects including the great green bush cricket (a species more common to the south coast) whose prolonged, shrill song can be heard on warm summer evenings. There are strong colonies of marbled white and chalkhill blue butterflies and you might be lucky enough to catch a glimpse of the fast-flying dark green fritillary or the silver-spotted skipper.

Buttler's Hangings, near High Wycombe
Aubrey Jenkins

Butterfly fact file

A chameleon in our midst
The green of the underwings of the green hairstreak butterfly is not made of pigments like other butterflies, but is produced by light reflecting from a microscopic lattice within the wing scales. Because of this, the colours that we see vary with the angle of view and the green hairstreak can appear to be anything from metallic apple-green to turquoise or even emerald.

Making the most of the summer
The common blue, like several other species, has two cycles of reproduction during one summer. The caterpillars that become the first brood of adults have hibernated over the previous winter and develop into butterflies during the spring. These butterflies will mate and lay the eggs which form the second brood, which hatch in September. The butterflies from this second brood mate and lay eggs quickly before the approaching autumn, and it is the resulting caterpillars that must then hibernate over winter, ready to form the first brood of the next year.

Lion of the local woodland
More than half of the butterfly species of Britain have been recorded at BBOWT's Warburg Nature Reserve - marbled white, small heath, common blue and green hairstreak to name just a few.

But Warburg is also a paradise for the rare purple emperor - the biggest woodland butterfly in Britain. It spends most of its time high up in the canopy, but occasionally males come down to the ground, showing off the brilliant purple sheen of their wings.

Purple emperors feed not on flowers, but from honeydew secreted by aphids, and even from dung and rotting animal carcasses - a real lion of the woodland!

To find out more about BBOWT nature reserves, volunteering and events please visit www.bbowt.org.uk or call 01865 775476.

Members of the Trust receive our events diary, a high quality magazine, and a detailed and beautiful book about the Trust's 88 nature reserves.

Hartslock Nature Reserve, near Goring.
Aubrey Jenkins

Above: A common blue.
Gavin Hageman

Nationally important for its archaeology as well as its wildlife, BBOWT's Seven Barrows Nature Reserve is an atmospheric site where butterflies abound amongst the Bronze Age burial mounds or 'barrows'.

The characteristic open, rolling grassland of the Berkshire Downs is the backdrop for the nationally rare marsh fritillary butterfly, and chalkhill blue, small blue, brown argus and marbled white butterflies. Only a mile outside of Lambourn, this compact nature reserve is perfect for a butterfly-spotting trip. The chalk grassland plays host to all sorts of plants and flowers from horseshoe vetch and fragrant orchid to the delicate blue harebell and clustered bellflower.

Try combining it with a visit to BBOWT's Watt's Bank Nature Reserve, just south of Lambourn, where, in only three small acres, an impressive 32 species of butterfly have been recorded such as green hairstreak, chalkhill blue and dingy skipper.

Visit www.bbowt.org.uk/all_reserves.html to find out how to get to any of BBOWT's nature reserves including those mentioned here.

Some other great places to see butterflies in Berkshire and the Chilterns include:

  • Ashridge Estate near Berkhamsted run by the National Trust - see www.nationaltrust.org.uk for details and events.
  • Greenham Common near Newbury jointly managed by West Berkshire Council and BBOWT - see www.greenham-common.org.uk for details and events.
  • Wildmoor Heath Nature Reserve near Bracknell jointly managed by BBOWT and Bracknell Forest Council - see www.bbowt.org.uk for details and events.

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