Spring Downland Butterflies (May):
Small Heath on Horseshoe Vetch Adonis Blues (Photograph by Andy Horton) Dingy Skipper (Photograph by Andy Horton)
Grizzled Skipper
Small Heath Butterfly
Adonis Blue Butterfly
Dingy Skipper
Grizzled Skipper

Noticable plants of the upper meadows include Greater Knapweed, Hardheads (=Lesser Knapweed), Field Scabious, Meadow Cranesbill, Alexanders, Pyramidal Orchids, Yarrow, Eyebrights, Musk Thistles, Sweet Violets, Horseshoe Vetch and many others.
Some Indicator Plants of Ancient Downland (Link)


The original historic reports state that originally a large part* of the downs including Mill Hill were presented to the people of Shoreham in 1938. (* The amount is still under enquiry.)

Just over 30 acres still remain as public open land. This is divided into about 11 acres of grassland and meadows above the ridge, about 9 acres of scrub, the copse and glades at the northern end, and about half of the prime Chalkhill Blue area of 6.4 acres of herbland remaining. 6 acres has been lost to a Sycamore woodland on the southern slopes. 

This is low fertility chalkland not suitable for grazing. The top area is effectively a wild meadow and the lower slopes a rabbit warren dominated by prostrate (not the upright form) Horseshoe Vetch

Chalkhill Blues:

Mill Hill is nationally important because of its population of Chalkhill Blue Butterflies. Estimates of the numbers are notoriously inaccurate. In the 1950s the population was estimated by R. M. Craske to be 50,000. This may be an exceptionally good year. I would estimate the numbers at that time to be nearer 25,000 for Mill Hill only. After the cattle grazing and thorn incursions the numbers plummeted to the most reliable estimate in 1960 of 6,000. The new road and Sycamore woodland further denuded the Horseshoe Vetch and bare chalk downland to a figure I have estimated at a top figure of 3,000 Chalkhill Blue Butterflies at the turn of the millennium (counted in 2003). Almost all these butterflies are now to be found on the six acres of the lower slopes. 
Graham Hart in the 1990s estimated the numbers at 6,000. This is not out of the question and this would accord with the R. M. Craske estimate of 50,000. This would be the maximum population density that could be expected on the carpets of Horseshoe Vetch (based on German figures)
Protection of the current population requires man management of the scrub incursions, which means removal of the Privet

Text by Andy Horton
Chalkhill Blue (Photograph by Andy Horton)
Chalkhill Blue Butterfly female
"Our family lived at The Mill House, Mill Hill, from around 1933 until about 1967, and every July we saw the "Butterfly Men" walking past onto the Downs. My father used to tell us that they were interested in the blue butterflies."
Heather Clark (née Eager), Ryde, Isle of Wight


20 June 2006
The first Marbled White Butterfly of the year fluttered strongly over the lower slopes of Mill Hill where the Horseshoe Vetch flowers had almost disappeared and the corkscrew-like seed pods could be discovered if searched amongst the emerging herbs and new flowers. The largest yellow patches on Mill Hill were now Bird's Foot TrefoilButterflies were frequent (about 50), but not common. The most prevalent on Mill Hill were now Common Blues and Small Heath Butterflies with about 15 each.
The hoverfly Rhingia campestris fed on Greater Knapweed on the middle Triangle area of Mill Hill. It was breezy at the top of the hill. Smooth Sow-thistle, Sonchus oleraceus, was recorded in the copse at the top of Mill Hill.
Butterfly Report & List
Adur Butterfly First Flight Times

Bee Orchid15 June 2006
With wild flowers bursting into flower everywhere, the highlight was about a hundred Bee Orchids in Mill Hill Drive. There was one Kidney Vetch flower seen on the Triangle section of Mill Hill. The first Greater Knapweed was seen in flower and Field Scabious.

About half of the 25 Adonis Blue Butterflies on Mill Hill showed signs of raggedness and age, whereas the Common Blues appeared fresher. I spotted my first Meadow Brown Butterfly of the year on the lower slopes, where I was surprised at a settled late Grizzled Skipper and I had a better look at a Large Skipper. There were eleven different species in an hour.
Full Butterfly Report
A Silver Y Moth, a Burnet Companion, a Treble-Bar and two pretty Mother Shiptons, Callistege mi, were all seen on Mill Hill.
A Skylark rose into the air.

12 June 2006
The first Meadow Brown Butterfly of the year was seen on Mill Hill. Other butterflies seen were Dingy Skipper (1), Small Heath (10), Adonis Blue (many, including several egg laying females), Common Blue (20), Brimstone (2), Small White (4), Painted Lady (1).

Report by Andrew Burns on Sussex Butterflies
Adur Butterfly First Flight Times

11 June 2006
Amongst the long grass meadow north of the top car park on Mill Hill, I had a brief sight of my first Large Skipper of the year (the only skipper of the day). I did not get a good a look as I would have liked to identify it, but Large Skippers precede the Small Skippers, so that is what it was. Adonis Blues (45 to 53 +) were most numerous on the lower slopes and the other species recorded were Common Blue, Large White, Speckled Wood (6), Holly Blue, Red Admiral and Small Heath (8).
Eight species.
Adur Butterfly First Flight Times
Butterfly Report (all sites)

Near the reservoir a group of five Magpies followed by a sixth were making a tremendous chattering racket.

On the lower slopes the Horseshoe Vetch had diminished considerably (it could not be seen from a distance), but the later growths on the middle and upper slopes showed patches even amongst the long grass with a handful of Adonis Blue Butterflies.
29 May 2006
The Old Erringham pastures were examined for their flora. It was quite different from Mill Hill with a higher proportion of grasses, but with a selection of herbs (excluding grasses), especially noting that the dramatic explosion of Bulbous Buttercups, with the blue Milkwort doing very well, and both Horseshoe Vetch and Bird's Foot Trefoil noted in small amounts. 
Adur Buttercups
Shoreham Bank with Horseshoe Vetch (not yet as extensive as 2005)
28 May 2006
Adonis Blue Butterflies were mating on the lower slopes of Mill Hill, with three mating embraces seen and at least another thirteen of these unattached bright blue butterflies flying around. Butterflies were seen in the morning included five Dingy Skippers, two Large Whites, and one each of Holly Blue, Red Admiral and Small Heath. This was less than usual for late May.
Adur Butterfly List 2006
Bulbous Buttercups in the rear and Horseshoe Vetch in the foreground Horseshoe Vetch Adonis Blues This Fairy Flax was spotted in the Old Erringham pasture

The prostrate Horseshoe Vetch was prevalent on the lower slopes, at about 70% of its luxuriance. Some flowers have not yet opened and it has appeared at the northern end which it usually does first, and has not yet appeared very much on the steeper banks, which are always a week later. In the Triangle area the Horseshoe Vetch was sparser than normal and on the upper plateau it was not prominent and was not instantly visible. Surprisingly there were some small patches of Horseshoe Vetch lost amongst the superabundant Bulbous Buttercups and a handful of patches of Milkworts in the Old Erringham pasture to the north-west of Mill Hill Nature Reserve. Also, in the meadow north of the upper car park, an erect variety of Horseshoe Vetch was spotted amongst the long grasses with a longer stalk (over 30 cm high, but still lower than the sward) and less leaves than the plant on the lower slopes. Summary: the Horseshoe Vetch is flowering over a week later than the last two years.
Herbs including Salad Burnet Cuckoo Spit (Click on the image for a close-up view) The wasp mimic is a hoverfly, a species of Chrysotoxum. Mushroom from the lower slopes, but also occuring above the ridge

I traversed the meadows around the upper car park and I did not note any butterflies although a Small Heath Butterfly was seen in the short sward near the reservoir. There were a few flying insects illustrated above in the dense meadows and at least one mushroom was noted in the short turf. The wasp mimic is a hoverfly, a species of Chrysotoxum.
21 May 2006
Three Swifts were seen (from southern car park of Mill Hill) flying over Frampton's Field before the cloud descended and obscured visibility and turned into steady rain that continued for the rest of the daylight.

Shoreham Weather News

Image: Alexanders and Cow Parsley on the southern part of Mill Hill Nature Reserve

Alexanders and Cow Parsley on the southern part of Mill Hill Nature Reserve

15 May 2006
My first two Silver Y Moths of the year flew from Frampton's Field, Old Shoreham. My first two Wall Brown Butterflies and my first Brimstone Moth were seen on a brief visit to Mill Hill. Two Partridges took flight from the Old Erringham buttercup-strewn pastures immediately to the north-west of Mill Hill. Silverweed was flowering on Mill Hill. The leaves of the Greater Knapweed were everywhere.
Full Butterfly Report

Eyed Hawk-moth, Smerinthus ocellata,14 May 2006
An attractive Eyed Hawk-moth, Smerinthus ocellata, was discovered on a Daffodil in my garden in Mill Hill Gardens, which was at one time part of Mill Hill.

Report by Paul Plumb
Adur Moths

At 10:00 am the resident Kestrel hovered in the overcast sky before the start of the Butterfly Walk on the lower slopes of Mill Hill which produced just two Small Heath Butterflies and a handful of small Pyrausta nigrata moths.The Horseshoe Vetch was just beginning, only about 5% of its full splendour. The sun struggled to come out in the afternoon and I recorded my first male Adonis Blue Butterfly of the year on the Shoreham Bank with 13 Dingy Skippers, five Grizzled Skippers and three Small Heath Butterflies.
Full Butterfly Report
Adur Butterfly First Flight Times
7 May 2006

A note was made of the Brown-tailed Moth caterpillars in their silk cocoons. The caterpillars seem to strip the upper leaves completely (in the one example noted) but most of the Hawthorn is still in leaf and not stripped bare. In the nearby Hawthorn without caterpillars, no damage can be seen. 

On the lower slopes the number of small moths were notable with both Pyrausta nigrata and Pancalia being common (over 100 each). Five each of Dingy Skippers and Grizzled Skippers were recorded with a Peacock Butterfly and a Large White Butterfly.

Butterfly Report
Adur Moths

1 May 2006
May came in with a shower. On the lower slopes of Mill Hill, the first Milkwort was seen in flower and the exiguous beginnings of the Horseshoe Vetch, Hippocrepis comosa. A single first Grizzled Skipper was recorded, the first of the year, with frequent (10+) small moths Pyrausta nigrata, seen for the first time this year,

26 April 2006
A Partridge whirred into flight on Erringham Hill as a Kestrel cruised overhead. South of the upper car park, a Rook probed the ground as a Skylark rose vertically and started singing until it was just a speck in the blue and white cirrus sky.
At the northern end of the lower slopes I spotted my first Dingy Skipper of the year that briefly sparred with a Peacock and the size difference was most noticeable. The Dingy Skipper is the first of I have heard of anywhere this year. A few Sweet Violets still flowered under the shade of the Hawthorn, but it was mostly Dog Violets in the open.
Adur Violets

24 April 2006
Half a dozen silken nests of the Brown-tailed Moths were noticed on Hawthorn trees on the southern part of Mill Hill.

19 April 2006
Andrena fulva (Photograph by Ray Hamblett) This attractive bee seen on the lower slopes of Mill Hill was the first time the Tawny Mining Bee, Andrena fulva, has been recorded on these Nature Notes pages. It is a female. The species is common and widespread. ID by Nicolas J. Vereecken on the Bees, Wasps and Ants Recording Society (Yahoo Group) 

Adur Bees

Caterpillar (Photograph by Ray Hamblett) There were many silk Brown-tailed Moth nests on Brambles at Mill Hill, Shoreham and a caterpillar noted and shown the photograph. The caterpillar was not connected to the silk nests and has been identified as an Oak Eggar Moth, Lasiocampa quercus, caterpillar (which does not associate with Oak).

ID by Trevor Boyd and Reg Fry on the UK-Leps (Yahoo Group) 
Development of the Oak Eggar (by Reg Fry)

Adur Moths

18 April 2006
Amongst the plants noted first in flower today were Dog Violets and Cowslips on the lower slopes of Mill Hill. But it was a remaining Sweet Violet that attracted a Peacock Butterfly.
Butterfly Report

9 April 2006
My first Swallow of the year flew low over the brow of Mill Hill and followed the country road northwards. Other Swallows had been seen by others in Sussex late in March.

Bee-fly6 April 2006
At last the first butterflies were seen on the lower slopes of Mill Hill: two definite Peacock Butterflies and at least one Comma Butterfly nectaring on the thousands of Sweet Violets in flower. There was a probable Small Tortoiseshell Butterfly as well.
Full Butterfly Report

A solitary Dotted Bee-fly, Bombylius discolor, a declining BAP species, was seen on a path through the scrub in the north-west and a tiny bee on a Daisy. This is the first time this fly has been recorded on the downs north of Shoreham.
Dotted Bee-fly (More Information)
Adur Flies 2006
Adur Solitary Bees

22 March 2006
Spring is imminent. There were Sweet Violets in flower one the slope by the most southerly seat on the southern section of the upper part of Mill Hill. These violets have large leaves. Then there were hundreds over the lower slopes of Mill Hill. These later violets have exiguous leaves. However, none of these violets were seen on the middle slopes in the Triangle area yet. The red stems of Dogwood were prominent. This woody scrub plant is the main incursor on the upper part of Mill Hill.
Adur Violets

2 March 2006
I surprised a female Sparrowhawk perched on a branch in the spinney between the top plateau of Chanctonbury Drive (SE of the bridge over the A27 to Mill Hill) and the A27. This is on the edge of the Mill Hill Cutting.  I got as close as two metres before the raptor flew off, but it was well camouflaged and it was not until I was three metres from it, did I see the bird of prey at all. It was much bigger with marked hooded eyes than the familar Kestrel and I estimated its height at 40 cm. This is much larger than the book size of the male which is only record to 30 cm.

17 February 2006
A flock of sheep are on the private agricultural hay meadow to the west of Mill Hill feeding on the stubble and grass as is usual for short periods in the winter.
There was absolutely not the remotest sign of the Sweet Violet clump flowering on the southern slopes of Mill Hill.
Adur Violets

1 February 2006
The cattle have been removed from the "lambing field" or intermittent pasture to the south-east of Old Erringham Farm and will not now venture on to Mill Hill. This is probably because the grass on the land has now been grazed to its optimum and is best left for the spring growth. This pasture is of no butterfly value although the fringes may contain the occasional wild flower.
January Cattle Report

The cattle are mostly on the paths where they deposit their dung30 January 2006
There are cattle all over Mill Hill from Old Erringham Farm enriching the low nutrient hillsides with their dung and threatening the flora (Horseshoe Vetch) and the internationally important population of Chalkhill Blue Butterflies. It looks like the fence was broken down deliberately, probably at the instigation of the South Downs Conservation Board on public land given to the people of Shoreham. There is also the danger or erosion, breaking up the steps under the hooves of the cattle and reduction of the amenity value of the downs. They were timid cattle and they were shooed of the vulnerable lower slopes by the public. Most of the dung was on the steps near the stile in the north-west corner of Mill Hill Nature Reserve.
First Draft of the Article for the Shoreham Society Newsletter

18 January 2006
There were a couple of House Sparrows next to a small eight caravan illegal encampment in the upper car park of Mill Hill which are unusual for this area. On the pastures to the east of Mill Hill a handful each of Rooks and Magpies were forgaging and on Mill Hill there were a few Crows. It is muddy under foot when human feet had trampled, with squelchy bits and puddles.

One tree on the upper slopes sported at least four of the common local lichens.

13 January 2006
My first visit of the year in the afternoon to the southern area and lower slopes of Mill Hill failed to find anything remotely newsworthy. The lower slopes looked more grassy than normal after the rain and there was still discarded chopped down Privet laying about. The remains of Carline Thistle were showing and the scrub was adorned by the straggly remains of Clematis. There was a discarded mushroom, which was probably Honey Fungus.
Pixie Path to Mill Hill (Link)

Mill Hill Wildlife Reports 2005 (Link)



Lower Slopes of Mill Hill


(Estimated numbers for Mill Hill Nature Reserve only are in brackets)
Chalkhill Blue (3000 +)
Adonis Blue (50 -100)
Dingy Skipper  (75)
Small Heath (250)
Wall Brown  (12)
Meadow Brown  (300)
Marbled White  (50)
Gatekeeper     (200)
Speckled Wood  (>50)
Green-veined White (2+)
Common Blue  (>3000+)
Small Blue       (5)
Brimstone        (8)
Small Skipper   (>50)
Large Skipper   (10+)
Grizzled Skipper  (20)
Brown Argus   (>30)

The other species may breed on Mill Hill, but there main breeding area will be adjoining fields or slightly further away. e.g. Small Blue (included above), Small Copper, Small Tortoiseshell, Green-veined White, Peacock, Ringlet, Small White, Large White, Comma, Holly Blue, Orange Tip. (=10)

The following are immigrants &/or hibernators:  Red Admiral, Painted Lady, Clouded Yellow.

The following have not been positively identified (because of ID difficulties):  Essex Skipper. This species is now included for a local field on the Adur Levels within 500 metres of Mill Hill.


The following may occur but it has not been positively identified (because it is elusive and hard to spot): Green Hairstreak.
The next one is no longer found on Mill Hill but were there in the recent (reduced drastically to almost extinct by 1948 last record in  1968) past: Dark Green Fritillary (Records of this butterfly in 1857, 1938, and 1945 when it was common.)
The next one is no longer found on Mill Hill but were there in the distant (1947) past: Grayling.
The next one has been recorded near Mill Hill in the middle distance past:  White-letter Hairstreak


The Silver-spotted Skipper does not appear to ever have occurred on Mill Hill
The Silver-studded Blue has never been recorded from Mill Hill

The Short-tailed Blue was recorded as a single immigrant in 1956.

Adur Butterfly Page


Link to the Mill Hill WILDLIFE REPORTS up to 2003
with lots of Butterfly observations

Lower Slopes (with Butterfly Reports)

Mill Hill Nature Reserve (including map)

MultiMap Aerial Photograph of Mill Hill

Back to Mill Hill
Upper Slopes
Middle Slopes
Lower Slopes
Grasses of Mill Hill
Mill Hill Copse

History of Mill Hill

Aerial Map
Lower Adur Levels (MultiMap) including Lancing Clump and Mill Hill

Hippocrepis comosa (Horseshoe Vetch)
First Draft of the Article for the Shoreham Society Newsletter

Link to Adur Valley Nature Notes 2003Link to the Adur Nature Notes 2004 Index pageLink to Adur Nature Notes 2005  Index pageLink to the Adur Nature Notes 2006 web pages