By Martin Kalaher
Chantry Hill is one of our top Sussex downland butterfly sites, but this princely accolade is not matched by the number of butterfly records sent in. In this article I will share with you some of its mysteries and delights and hopefully this will encourage a few more visitors (and a few more records!). What I won’t be sharing with you are any of my photographs, for all the images have been provided by Katrina Watson and John Williams – my thanks to them both.
For those who are not familiar with Chantry Hill I will set the scene with a geographical outline and mention a few highlights for each of the three combes. Following on, there is a brief personal exploration and then a summary of all the butterfly species that may be recorded, annually.
Chantry Hill is located to the south of Storrington and is easily accessed by driving to the Chantry Post car park, via Chantry Lane. The main east-west footpath of Chantry Hill is accessed from Chantry Lane, around 150 metres to the north of the car park. It is divided into three combes, which I will label east combe, middle combe and west combe. All three have impressive steep-sided slopes which at first glance may appear rather forbidding. They can be explored fully by descending to the bottom of each valley but there is a gentler alternative, which I shall explain in due course.
Both the north and west-facing slopes of the east combe are covered with
Yorkshire-fog and other tall grass species and therefore most of the chalk
grassland of this combe is considerably less biodiverse compared to the
other two. However, what it lacks in both floral and insect diversity it
can more than make up with astonishing numbers of butterflies that may be
found here. In June 2016 there were 3-4000 Small Skippers and 1500 Marbled
Whites recorded on these two slopes. When cattle were re-introduced to
Chantry Hill 4-5 years ago it was this area of Chantry Hill where the gains
were most obvious. Within 1-2 years of winter grazing there was a marked
improvement in some parts of this combe with significantly greater flora
diversity. Many hundreds of Cowslips, various scabious species and other
downland wildflowers began to appear amongst the rank grass species.
East Combe TQ 08872 12274
This is the hidden valley of Chantry Hill. Protected by very steep slopes
please do not venture forth unless you have good balance and a strong
heart! Should you explore it fully you will not be disappointed for there
is so much to discover. From the main east-west footpath descend into the
combe, initially heading for the centre. Halfway down the slope, take the
right-hand margin of an island of scrub and bramble, which is situated just
left of centre. All along this margin you will find an interesting variety
of male butterflies on territory. At the bottom of this scrub/bramble
island there is a small patch of chalk turf which abuts the east-facing
slope. In an area no more than 50 metres square you will find all “the
Blues” and much, much more. It is a delightful spot and well-worth a half
hour of your time, for there is so much to see (and anyway, you have a
steep climb ahead of you so will need a snack and some fluid before you
Middle Combe TQ 08637 12466
Back on the main east-west footpath continue west and you will come across
a right-hand fork that takes you to Greyfriars Farm and on to Storrington
(with the main east-west path leading you to Kithurst Hill). There are two
butterfly-rich areas to explore along this right-hand fork. Just 80-110
metres along this footpath there is an embankment to your left. This is
part of the archaeological remains and is one of the best places to look
for both Silver-spotted Skippers and Dark Green Fritillaries, two of the
iconic butterfly species that have colonised Chantry Hill. The top of this
embankment is full of Hairy Violets and in a good year one may find 30-50
Dark Green Fritillaries in just 100 metres square of downland. Back on the
footpath, head towards the Greyfriars Farm exit. Approximately 100 metres
before leaving the chalk grassland there is a sharp right-angle bend to the
footpath, heading due north. Leave the footpath to your right and head
towards the woodland margin at the bottom of the hill. This whole area is
excellent for butterflies but especially where the chalk turf abuts the
woodland margin. One can often record a dozen butterfly species in as many
minutes and is one of the few locations in Sussex where Dark Green and
Silver-washed Fritillaries regularly fly side-by-side. Many of the
butterflies present here are males on territory and this is as good a place
as any to watch the disputes of feisty near-neighbours.
West Combe TQ 08531 12678
Several times every summer I leave the sanctuary of my Storrington wildlife garden, access the nearest footpath and go tramping over Chantry Hill. It’s taken a few years, but I have gradually discovered all the best nooks and crannies and now have a very good idea as to where most of the butterfly colonies may be found. I now have an established route, which I always follow, and if the weather is kind, I reckon to complete a comprehensive butterfly survey in around four hours. I am never disappointed for one way or another Chantry Hill always delivers something of interest. It helps that I have a broad passion for natural history and enjoy in equal measure a Red Kite sailing overhead, discovering a clump of our native Betony or watching a male Brown Argus giving chase to all-and-sundry. It’s all part of the natural world of Sussex downland, and all equally beguiling.
So why is Chantry Hill so special? Well it’s got everything really, beginning with the view. Everyone will have their favourite Sussex view but the vista-to-the-north from the top of Chantry Hill must surely feature in the top ten! Then there are the birds that grace this area with their presence. There is almost always an up-draught available at Chantry Hill, regardless of the direction of the wind. The steep scarp slope is north-facing but additionally there are east and west-facing slopes of the three main combes. These up-draughts can be a problem for our butterflies but many of our raptor species and all the corvids just love it. Kestrels, Sparrowhawks and Common Buzzards are resident with Red Kites seen daily. Ravens are always present, and it has become the best place in Sussex to see large flocks of immature birds, often numbering 20+.
The flora is an absolute joy. With thin soils over-lying porous chalk, the variety of native wildflowers is astonishing. Every summer I discover different plant species that I didn’t realise were there. This year I found a bank full of Wild Basil in the middle combe and thousands of Wild Strawberry plants, courtesy of the recent scrub and bramble clearance on the east-facing slope of the middle combe. There is a wonderful variety of wildflowers at Chantry Hill but the dominant species that carpet the slopes are Cowslip in the spring, Marjoram in mid-summer and Devilsbit Scabious in late summer/early autumn.
Approximately 37 butterfly species may be seen at Chantry Hill, with the potential for the occasional visitor to add to the total. It can be much colder than other Sussex downland sites and as a rough-and-ready rule, the season is around two weeks behind other “warmer sites” such as Mill Hill. It is a windy location (and let’s face it, butterflies do not like windy conditions) but as there are slopes facing north, east and west there is usually somewhere that is protected from the prevailing wind (and if in doubt where to explore, try the lower slopes and especially the valley bottom of the middle combe). Working our way through the butterfly list I shall add in brackets the numbers I have recorded as a peak daily count over the past few years. Now, where shall I begin?
Six members of the skipper family are regular at Chantry Hill: Small Skipper (3-4,000), Essex Skipper (20-50), Silver-spotted Skipper (30-75), Dingy Skipper (100-150), Large Skipper (30-60), Grizzled Skipper (15-25) and Dingy Skipper (100-150). The skippers may be the “little brown jobs” of the butterfly world but for me they are attractive little butterflies, challenging us to identify them correctly and not always keeping still when we reach for our cameras. Chantry Hill is one of the few sites in Sussex where all six skippers may be found and recorded in good numbers.
Our skipper species can be quite fussy with their habitat requirements, as Silver-spotted and Grizzled Skippers need very short turf, Dingy Skippers can cope with a slightly higher sward, whilst Small Skipper, Essex Skipper and Large Skipper are generally found where the grass species are much taller. Chantry Hill is blessed with a fine variety of grassland habitats, thus accommodating the needs of all six skipper species. Most of the chalk turf of the west combe and the middle combe is kept short/fairly-short turf by the constant nibbling of rabbits and deer. By contrast the sward height of the east combe is much higher and dominated by coarse grass species, with far fewer wildflowers.
As Small, Essex and Large Skippers are widespread and fairly common throughout Sussex, I will leave them aside and concentrate on the other three. In the paragraph above I have described the skippers as being rather fussy, which may seem a slightly odd description? The underlying truth is that their larval food plants are the fussy ones and require very particular conditions if they are to survive/thrive. For these three uncommon skipper species the principal/sole larval food plants are as follows: Sheep’s Fescue (Silver-spotted Skipper), Wild Strawberry (Grizzled Skipper), Horseshoe Vetch and Birdsfoot Trefoil (Dingy Skipper). The first three on this list are all low, ground-hugging plants that cannot compete with larger, taller more vigorous vegetation. They can only survive where the turf is very short, which in turn emphasises the importance of grazing rabbits (at this location). As the caterpillars of Dingy Skippers may feed on both Horseshoe Vetch and Birdsfoot Trefoil this species can exploit a greater range of grass habitats and so the sward height is rather less critical for this species. This probably explains why there is a such large colony of Dingy Skippers at Chantry Hill (with daily counts of 100-150+), compared to the other two skipper species.
The “Whites and Yellows”
Six members of the “Whites and Yellows” are regular at Chantry Hill: Clouded Yellow (2-4), Brimstone (10-20), Large White (10-20), Small White (10-20), Green-veined White (2-5) and Orange-tip (4-6). These species do not form discrete colonies but roam the countryside seeking out mates and egg-laying opportunities. None of these butterflies are especially common at Chantry Hill. Migrant Clouded Yellows may be found in any of the wildflower meadows, but the middle combe is the most reliable place to find them, as there is usually plenty of nectar available and the valley bottom is generally “out of the wind”. The other “Whites and Yellows” can be found on the margins of the west and middle combe.
Seven of the eight Sussex “Browns” may be found at Chantry Hill and some of them in very good numbers, as follows: Wall Brown (5-12), Ringlet (30+), Meadow Brown (3,000+), Speckled Wood (3-6), Small Heath (500+), Gatekeeper (10+) and Marbled White (3000+).
There is a small Wall Brown colony, which can be located along the main east-west footpath at the southern end of the west combe. There may be 2-3 males on territory on the main footpath itself, with others in and around the archaeological remains. The discovery of several small colonies of Ringlet was one of the surprises of 2018. Chantry Hill is mostly “open aspect” terrain but there are many small islands of scrub/bramble and where the scrub is six feet or higher you are likely to find Ringlets. Meadow Brown can be very common, and it is usually the commonest butterfly species recorded, sometimes 3000+ as a daily count. There are always a few Speckled Wood around the northern margins, and a few Gatekeeper on the hedgerows in the north-east of the conservation area. Marbled White numbers vary enormously from year to the next but in the summer of 2016, they were astonishing numbers with around 3000+ as a peak daily count.
The Violet-feeding Fritillaries
Two members of the violet-feeding Fritillaries are regular at Chantry Hill: Silver-washed Fritillary and Dark Green Fritillary. Silver-washed Fritillaries may be located in the north-west of the reserve. Walking in from the Greyfriars Farm footpath they may be seen to the left of the path as you climb the steep slope towards the open area of Chantry Hill. Otherwise, the odd one can be seen flitting around the area “where the chalk turf abuts the woodland margin” (see West Combe, above).
As for Dark Green Fritillary I will quote Neil Hulme from The Butterflies of Sussex, when he describes the dramatic change in fortunes for this species, as a result of the resumption of cattle grazing – For some years previously, the Dark Green Fritillary had been a sufficiently rare sight along this stretch of the South Downs for a single specimen to cause considerable excitement, and maximum daily counts had been to ones-and-twos each season, if seen at all. However, the local population reacted to the improved habitat conditions with enthusiasm, with maximum day counts reaching 55 in 2013 and 65 in 2014. On a July day during the first post-atlas recording season, 2015 a daily minimum of 140 individuals were counted. Chantry Hill now hosts the largest population of Dark Green Fritillary in West Sussex, which may be growing. It was indeed still growing for in June 2016 the daily count peaked at 212.
At their peak Dark Green Fritillaries may be found anywhere at Chantry Hill but the upper one third of the slopes of the middle and west combes are rewarding as is the embankment by the archaeological remains. For photography I would recommend the many thistle heads that can be found on the valley bottom of the middle combe.
Five members of the Aristocrats are regular at Chantry Hill: Red Admiral (10-20), Painted Lady (3-6), Peacock (1-4, Small Tortoiseshell (1-5) and Comma (1-5).
Many of our migrant species stop off on Sussex downland hilltops, and both Painted Lady and Red Admiral can often be found on the main east-west footpath, in around the shrubbery just to the south of the archaeological remains at west combe. Otherwise, when the brambles are in flower check out the large clump of brambles that adorn the shrubbery 20-30 metres down the slope where the right-hand fork footpath leaves the main east-west footpath. In 2018 I recorded a minimum of five Painted Lady re-fuelling on this patch of bramble. One or two Small Tortoiseshell can often be found along the bank of the main east-west footpath.
None of these Aristocrats can be considered common at Chantry Hill but the far southern end of the middle combe is a good place to check for them. Adjacent to the main valley bottom there is an un-grazed meadow full of nettles and nectar-bearing native plants and one can usually find a good variety of Aristocrats there.
Duke of Burgundy
There is a meta-population consisting of 7-8 small colonies of Duke of Burgundy spread thinly over the Storrington downland. In this area it is the colony at Kithurst Hill that is most readily found and where many fine photographs are taken every year.
Coppers, Hairstreaks and Blues
Ten members of the Lycaenidae family may be seen at Chantry Hill as follows: Green Hairstreak (30-160), Purple Hairstreak (1-2), Brown Hairstreak (1-2), Small Copper (3-6), Small Blue (8-15), Brown Argus (50-100), Common Blue (150-800), Chalkhill Blue (30-80), Adonis Blue (1) and Holly Blue (1-4).
Green Hairstreaks cannot be considered a common butterfly species in Sussex, but this is one location where they can be recorded in very large numbers. The territorial males choose a variety of shrubs on which to perch but here they generally favour Hazel. They can be very common on the scalloped margins on the west side of the west combe and the east-facing slope of the middle combe. I have counted 30 territorial males in a 25 metre length of Hazel scrub, with more-or-less constant aerial battles between neighbours, sometimes involving 5-6 individuals. Common Ash and Beech dominate the woodland surround to the conservation area but there is some Oak where the odd Purple Hairstreak may be found. Brown Hairstreak is also present but in very small numbers. Both of these hairstreaks are common just a few hundred metres away in the fields surrounding Storrington.
In a good year Common Blue can be counted in the 100s but the numbers do vary considerably from one year to the next. The Chalk Hill Blue population is modest for a site of this size and Adonis Blue has yet to become established, although with quite a few second-generation Adonis Blue recorded at near-by Kithurst Hill in 2018, this may be about to change. There isn’t much Kidney vetch at Chantry Hill and so the Small Blue colonies are likely to remain modest in size. By contrast Common Rock-rose is plentiful, and Chantry Hill has one of the largest colonies of Brown Argus in Sussex. There are always a few Holly Blue to be found on the western and northern margins.
As I live in Storrington I usually walk from my house in Kithurst Lane, access the nearest footpath (marked A on the map) and then head towards Chantry Hill via Greyfriars Farm. A couple of hundred metres past the farmhouse the footpath forks, with the right-hand fork leading to the open area of Chantry Hill. Around 80 metres up this slope I leave the footpath to my left and explore the chalk grassland/woodland interface. For such a small area this is remarkably rich in butterfly species and as previously mentioned one can often find a dozen species in as many minutes. From there I head due south, back towards the main footpath. Bearing right I then explore the scalloped area on the far west of the conservation area and gradually work my way around the western edge of the west combe and then straight up the hill towards the archaeological remains. Continuing due south, I cross the high bank of these remains towards the main east-west footpath. This is where you can find a lovely variety of species, including Small Blue, Silver-spotted Skipper, Dark Green Fritillary and Wall Brown. Now on the main east-west footpath I head east, take the left-hand fork (back towards Greyfriars Farm) and then after 80 metres or so work my way down the east-facing slope of the middle combe (where the scrub has been removed in recent years) and where any number of species may be found, including Green Hairstreak, Silver-spotted Skipper, Dingy Skipper, Grizzled skipper and many, many more. Down the bottom of this slope where it abuts the valley floor is arguably the best place to find all the chalk specialist butterfly species. In just 50 metres square they can all be found. From there I head through the valley bottom and explore the meadow to the north, where Red Admiral, Comma, Small Tortoiseshell are often present. Returning to the middle combe I then head east and make my way towards the east combe, exploring any patches of scrub I come across. Then a steep climb back towards the main east-west pathway. This slope is covered in Yorkshire-fog and in a favourable year there may be 1000s of Small Skippers present and many hundreds of Marbled White.
A much shorter route and one that avoids most of the steep slopes can be taken from the Chantry Post car park (marked B on the map). Walking back down Chantry Lane the main east-west footpath is accessed. If it is a bumper year for either Small Skipper or Marbled White it is very worthwhile going down the slope of the east combe but only the top 50 metres or so. Then return to the main east-west footpath and just before reaching the middle combe leave the main footpath and head due north. You don’t have to go too far down the slope (in late June/July) when you may be surrounded by dozens of Dark Green Fritillaries. Return to the main east-west footpath and take the right-hand fork footpath towards Greyfriars Farm. All along the left-hand side of this path Silver-spotted Skippers and Dark Green Fritillaries may be found. Head down the footpath towards Greyfriars Farm but before the footpath enters an area of woodland (and the exit to Chantry Hill) turn right and check out the area of chalk turf/woodland interface previously alluded to. Then return towards the car park. This walk is around 2-3 kilometres and only involves one moderately steep climb.
The very steep slopes of Chantry Hill protected it from the plough in the Second World War and to this day the slopes continue to protect its three combes from casual footfall. Should you decide to explore its guarded valleys you will not be disappointed for there are few places in Sussex where one can find such biodiversity. There is pristine chalk turf, grassy meadows, hedgerows, shrub and all of this bordered by woodland. It is this variety of vegetation in just one square kilometre of downland that creates this diversity and therefore its appeal. Some 37 butterfly species may be recorded annually, the wildflowers are wonderful, and unusual birds such as Red Kites and Ravens in daily attendance. What more could you ask for?
Well, it can be a cold, windy place and so choose your day carefully and it goes without saying that ankle boots are necessary as is a snack and some fluids. This may not be the Matterhorn, but you need to be prepared for there are plenty of rabbit holes itching to trip the unwary and you really don’t want to face a steep climb without a little nourishment and re-hydration!
As for the butterflies, well there are a lot of highlights to choose from. Six species of Skippers and in very good numbers is a nice starting point. Of the six Whites and Yellows, the migrant Clouded Yellow always makes an appearance in the middle combe at some point during the summer/autumn. The Browns are very well represented and in good years there are very large colonies of Meadow Brown (3000+), Small Heath (500+) and Marbled White (3000+). From a single egg-laying Dark Green Fritillary to a colony exceeding 200 (in a just a handful of years) is a spectacular success story; courtesy of a well-thought-out conservation strategy and a small herd of cattle! The Aristocrats can be seen anywhere in Sussex but migrants such as Painted Lady may land and re-fuel in significant numbers. A few Duke of Burgundy may be seen and there are large colonies of Green Hairstreak, Brown Argus and Common Blue.
I always look forward to my next visit to Chantry Hill for it never fails to deliver something a bit different, something a bit special. Perhaps when I am doing one of my 2019 butterfly surveys, I will bump into one or two of our Sussex BC members?
There are some beautiful photographs shown above and none of them are mine. My thanks and congratulations to Katrina Watson and John Williams.
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