Getting there

Collard Hill is just south of Street in Central Somerset.

The site is immediately east of the B3151 Street to Somerton road, in the south-east sector of the cross roads between this B road and the ridge-top C road that runs west to east from Berhill (Ashill) to the Butleigh Monument.

The grid reference for the centre of the slope occupied by the Large Blue is ST 488 340.

• How to get to Collard Hill on the Multimap website

The butterfly now flies all along a quarter of a mile stretch of steep, south-facing slope at Collard Hill.

The slope is exposed to southerly and westerly winds, and on windy days the butterfly will seek the shelter of the scattered scrub patches. (The slope to the east of the cross slope barbed wire fence is in private ownership and does not support the butterfly.)

© Matthew Oates

Parking

Please park in the National Trust car parks opposite the Youth Hostel on Ivythorn Hill, grid reference ST 482 344. These are off the Street to Berhill road, due west of the Collard cross roads (along the hill top road). Look for the Large Blue sign. There is an interpretation board in front of the youth hostel.

You will then need to walk approximately 200m eastwards along the paths through the grassland on Ivythorn Hill, on the north side of the road, towards the cross roads, following the blue-topped posts.

Access to Collard Hill is through the footpath gate in the south-east sector of the cross roads (head towards the scattered Scots pine trees on the slope).

Please take great care when crossing the road as visibility is limited and vehicles travel at speed - over a blind summit with a 60mph speed limit.

It is possible to drop passengers off in a pull-in along the road leading east from the cross roads to Butleigh Monument. They will then need to cross a stile and head up the gentle slope, southwards. We recommend this route for people who might find the cross roads difficult.

Note that pulling out eastwards from this pull-in is difficult. It is best to turn round first and head towards the Ivythorn car parks. We do not recommend parking here as break-ins have been known to occur.

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Accessibility

In addition to the difficulty of crossing the cross roads, please note that the Collard Hill slope is steep, hard and bumpy, and is very slippery when wet, so please wear walking boots (not wellingtons) and take care. Sandals are inadvisable.

The Large Blue flight season is notoriously difficult to predict, and depends much on the weather.

Normally, the first males should appear around 7 June and numbers should be best during the third week of June, possibly the first days of July.

• For up to date information please phone the National Trust Large Blue phone line

At present, you should manage to see at least half a dozen Large Blues in an hour of suitable weather. In hot weather they tend to have a siesta during the early afternoon.

How to identify the Large Blue

Large Blues appear in various guises: they can look small, large, dark, dull or bright. The only other blue butterfly present on Collard Hill with which it can be confused is the common blue, which is generally smaller and lighter, has no black spots on the uppersides and has orange spots on the undersides. The first brood of the common blue should be virtually finished at Collard Hill by mid June.

Both sexes of Large Blue take nectar from low-growing plants, especially wild thyme. It is difficult to tell the sexes apart, especially since the males visit wild thyme flowers and gyrate their hind wings in the manner of laying females.

© National Trust

© National Trust

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2009 Open Day: Sunday 21 June

Collard Hill is always open, and visitors are always welcome, but the Trust is making a special effort to welcome visitors and facilitate visits on Sunday 21 June this year, from 10.00am to 5.00pm. We will have an extra number of wardens and volunteers present then.

Facilitating visits and visitor numbers

The Trust runs a dedicated phone line from approximately early June through to mid-July. It is regularly updated. Its main aim is to guide people as to when and when not to visit! Calls are charged at standard rate. There is no answer phone facility.

It is strongly advisable to phone this number before visiting, especially if travelling any distance.

There is always at least one person on hand (at least two at weekends) to facilitate visits at Collard Hill.

The following table shows the numbers of recorded visitors since Collard Hill opened in 2002:

The hill tends to be quite busy on sunny weekends during the Large Blue season, when we record over 50 visitors a day. In the early years the butterfly was largely confined to one part of the site, but it is now flying all along the slope, which helps to spread the visitor load nicely. If you want peace and quiete, come early or late in the day - for Large Blues can be quite active then in hot weather.

People visit from all walks of life, not just butterfly buffs and photographers. A large number of local people visit and we are starting to receive more visits from families and people who are not dedicated specialist naturalists. Visitor of the Year 2006 was a five day old baby!

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© National Trust

How is the Large Blue doing at Collard Hill?

The Large Blue was introduced to Collard Hill in 2000, as a translocation from an established population a few miles away. Since then it has had a couple of difficult years, due to poor weather and / or difficulties in arranging appropriate grazing, but it is now doing very well and is almost certainly set to increase much further.

The population is monitored by two methods: a standard butterfly transect that is walked daily in suitable weather, and detailed egg counts of eggs are made after flight season has finished.

The following table shows the number of Large Blues recorded on transect each year:

We anticipate the population to increase further, though not necessarily every year. It may well double or treble within the near future. But, of course, much depends on the weather, particularly during the flight season in June, but the butterfly can also be adversely affected by drought, especially in spring.

When is the Large Blue flying at Collard Hill?

Large Blue flight seasons are notoriously difficult to predict, and remember that the Large Blue is not a typical butterfly, spending much of its life underground!

The following table shows the structure of the flight season from 2002-08. It provides a useful guide.

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Grazing and Habitat Management

Initially it proved difficult to achieve the right level of grazing on the slope where the Large Blue breeds. Much of the western end of the slope was dominated by tall Upright Brome grass, a coarse grass that grazing animals do not favour. But spring grazing has tamed this grass and greatly increased the area of short turn suitable for Large Blue butterflies.

We had to erect a fence along the crest of the hill to achieve the necessary control of grazing. This enables us to move animals on and off the Large Blue’s slope easily, without causing over-grazing or under-grazing. We also had to place water troughs in both these compartments.

The Large Blue is totally dependent on grazing by farm stock at Collard Hill. We are highly fortunate in that a local farming family, George & Pat Burroughs from Home Farm, Butleigh Wood, have taken on the challenge admirably. The butterfly would not persist without their efforts.

George runs his beef cattle on the hill and Pat has purchased some Dartmoor ponies specifically to follow on from the cattle. It is especially important that we graze the site hard in May, to counter the year’s main pulse of grass growth, and then remove stock before the flight season begins.

Pat and George also provide accommodation for the seasonal Large Blue Warden. They are key partners in the Collard Hill venture.

Trust wardens and volunteers manage the scrub positively. There is no scrub invasion problem on the hill, and the blackthorn scrub supports the scarce Brown Hairstreak butterfly. Scrub management is really a matter of cutting bays to provide shelter for butterflies in rough weather, and occasional patchy coppicing.

Group Visits

Please contact the National Trust North Somerset office first (01934 844518) if you would like to make a group visit to Collard Hill.

Matthew Oates - National Trust butterfly specialist - February 2009

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