Butterflies and moths overwintering in the Newhaven Fort tunnels

Our third year of surveying overwintering insects and bats in the tunnels at Newhaven Fort started on 14th December. The Fort management team kindly allows us access to the tunnels which are closed to the public at a time when the Fort itself is closed for winter maintenance. 

Peacock in diapause (Vanessa io)

Of the few butterflies which spend the winter in diapause, species like the Red Admiral (Vanessa atalanta) tend to prefer the cover of thick vegetation rather than a subterranean hibernaculum. They are the last species on the wing in most years and often one of the earliest seen the following year. We have never found Red Admirals in the tunnels. Peacocks (Vanessa io) and Small Tortoiseshells (Aglais urticae) are often seen on a warm morning in February or March basking on the bare ground around rabbit warrens, having emerged from within the holes. The Newhaven Fort tunnels offer a similar refuge and we find both species in small numbers here.

Bloxworth Snout (Hypena obsitalis)

Of all the insect species found overwintering within the tunnels, we are most interested in the Bloxworth Snout (Hypena obsitalis), a moth which is in the process of colonising coastal Britain from the south. It feeds as a larva on Pellitory-of-the-Wall, a nettle which grows in walls and crevices, hanging on along the edges of things - a bit like the Bloxworth Snout itself. The Newhaven Fort tunnels are emerging as one of the best spots in the UK known for this moth.

Bloxworth Snout (Hypena obsitalis)

Another notable moth we find is a well-known overwinterer, The Herald (Scoliopteryx libatrix). This species feeds on poplar and willow and there are a few of these trees in the northern edge of the Fort and Castle Hill Local Nature Reserve. This species has been seen in single figures in previous surveys. It is a common but beautiful moth which looks like an autumn leaf.

Eristalis tenax hoverflies clustered beneath a paint blister

In addition to these core species, we usually also see good numbers of the Twenty-plumed Moth (Alucita hexadactyla) which feeds as a larva on the abundant honeysuckle growing at Castle Hill LNR, a few Common Flat-body (Agonopterix heracliana) and a few individuals of the Fleabane Smudge (Digitivalva pulicariae), which are curiously found deep within the tunnels far from an obvious point of entry. All the other moths and butterflies we see are found fairly close to the open air, in the company of bristletails (Petrobius maritimus), various woodlouse species, slugs and snails, several species of midge and lots of spiders. Their prerequisites appear to be a stable temperature and some ventilation with protection from the weather, predators and pathogens. Some light intrusion to indicate changes in day length is probably also an important guide to the right time to re-emerge the following Spring.

So to 14th December 2016. Five of us ventured underground on what was a sunny winter day with a moderate southerly breeze blowing warm air across the English Channel from the continent. This weather pattern had been in place for several days prior to our visit and followed a period of colder weather with a number of overnight frosts. It's a shame the frosty weather hadn't lasted until our visit as this would have allowed an interesting comparison with previous years' surveys, which have always taken place during mild weather, but the mild weather did allow a direct comparison this year with the previous two. The thermometer read 13°C, which is pretty warm for a clear December day. Temperatures in the tunnels ranged between 12°C and 13.5°C. Here's what we saw:

Peacock (Vanessa io) (17)
Small Tortoiseshell (Aglais urticae) (9)
Twenty-plume Moth (Alucita hexadactyla) (67)
Herald (Scoliopteryx libatrix) (31)
Bloxworth Snout (Hypena obsitalis) (10).

Five species is the fewest we have seen since we started surveying the tunnels, yet we saw more individuals overall and beat our previous record of 112 by quite a margin: this time we saw 135. The reason for this was a significantly greater number of Twenty-plume Moths (December average is 40) and Herald (December average 7.5). It is misleading to place too much relevance on only a few years' data, but this December we saw a 67% increase of Twenty-plume Moths and a more than 400% increase of Herald.

The value of regular surveys grows with the accumulation of comparable data from year to year and we are beginning to see some interesting patterns emerge now that we are into our third year of monitoring. Observing overwintering insects also reveals a surprising insight into different species' behaviour. Predictably perhaps, warmth-loving butterflies tend to be in a much deeper state of diapause than moths, which are more tolerant of cooler temperatures. The Bloxworth Snout is particularly tolerant of low temperatures, often entering a shallow state of torpor rather than proper diapause. This ability to remain active at times when predators or competitors may be less active might offer a selective advantage as it radiates northwards into new territories, but it might consequently also be more at risk of severe cold snaps. If more people were able to inspect overwintering sites each year it would almost certainly help improve the understanding of how weather and climate influences the population dynamics not only of moths or butterflies but also all those species associated by a complex web of interaction.

The reasons for the increases in some species this December might be that the weather was good when the adults we saw were progressing through their earlier life-stages; it might be that predators and pathogens were fewer; it might be that previous years were influenced by adverse conditions at the time and we are now witnessing a regression to the mean. Whatever the reasons, the other species we saw this time were at much the same levels as in previous surveys. Questions arising from the collected data are exactly what is hoped for. Some of these questions might be answered if we can continue to collect data in future years.

A cluster of Herald (Scoliopteryx libatrix)

Early April at Barrow Head

Transect walking season, weeks one and two

It is the second week in April. My good friend David Harris and I have started our annual season of  transect walks around Newhaven's Castle Hill Local Nature Reserve. We will share alternate weeks between now and the end of October, or whichever time of year that there are too few butterflies on the wing to make the walk worthwhile. This is the sixth year that the transect has been walked and it has become a staple of my wildlife year. It is sometimes a tough commitment in high summer, when all the daily demands of life are queuing up impatiently asking for attention, but the transect walk is always a joyous few hours' escape from everything other than what can be seen before you.

David has walked week one; week two is my turn (David odd; Steven even). In week one only a single butterfly was seen: a Small Tortoiseshell (Aglais urticae) on the clifftop at the extreme west of the nature reserve. We have never had a quieter start to the season.

To compensate for the lack of butterflies and moths, David did make an excellent sighting of the Forget-me-not Shieldbug  (Sehirus luctuosus), also along the clifftop but just to the east of the headland known as Barrow Head. This is not a rare insect, but it is not common either and it's a new species added to our site list. It's food-plants (Forget-me-not or Myosotis species within the Borage family) can be found in quite a few places around the reserve and include Early (Myosotis ramosissima) and Field Forget-me-not (M. arvensis), which are just coming into bloom now, as well as the later flowering species Wood (M. sylvatica)  and Changing Forget-me-not (M. discolor). If luck is with you, you might be fortunate enough to see the small black bug crawling on the ground around the plant or perhaps basking on a leaf.

I have just completed the week two walk around Castle Hill. I am out early because the early morning sun is forecast to be replaced with cloud from late morning onwards. I have seen only one butterfly: a Peacock (Aglais io), on the sheltered glade on the north slope of the reserve. Other insects of interest seen included quite a few Dark-edged Bee-flies (Bombylius major) and an extraordinary number of Buff-tailed Bumblebees (Bombus terrestris) - several hundreds or more all basking in the sun, nestled and half enveloped in grass everywhere along the transect route. It is as though all the bees have been placed under a soporific spell.

As I return to my car, which is parked beneath Barrow Head, I am distracted by an attempted robbery: a lone Raven is visiting each of the many Jackdaw-hollows in the chalk along Barrow Head in search of Jackdaw eggs, like a taxman making house-calls. The Jacks are brave and mob the intruder as it moves systematically from one hole to the next. The Raven visits each hollow not with a short hop but with an exaggerated flycatcher-like loop away from the cliff and back again, tracing a teardrop in the air.

These are both Corvid species, but they are the largest and the smallest and the difference in size is startling. Their evolutionary close kin-ship stands for nothing. The Raven goes calmly about its business and appears to be indifferent to the smaller Jacks as they cartwheel through the air, but the hollows are all empty. It seems the Jacks are still nest-building and have not yet laid their clutch. The Raven perches on the ledge of each, looks monstrously within, pauses for a moment and loops back into the air. With all the house-calls made, the Raven moves away penniless in an eastward direction and the drama is over.

A slab of early morning cloud has drifted off to the east and the spring sun warms my back, while a chilly breeze frisks me from the west, chilly enough to usurp any comfort offered by the sun. As the Jackdaws and Feral Pigeons settle, I climb the slump past them and past Barrow Head on its east side towards a flush of golden flowers which have caught my attention and I find myself suddenly out of the influence of the breeze. Here, it is another day; a hot, calm morning in summer. The heat of the sunlight uninhibited by the breeze is astonishing.

Water-pepper - I think

The flower is Lesser Celandine (Ranunculus ficaria). The starburst flowers open only in sunlight, forming a mirror-mat of gold amidst a nest of heart-shaped green glossy leaves. It is a welcome sight, doubly so because they are the first I have seen on the ground we cleared a few weeks before when we were cutting brambles. It might have grown amongst the thorns in previous years, but it could be a pioneer. This flower, for all its early season beauty, is actually an invasive pest which is blooming amongst the grass in most areas across the reserve. A few steps away is a seasonal pool with what appears to be leaves of Water-pepper (Persicaria hydropiper) reaching up above the surface. It is a plant of winter-wet places. In summer its tresses of pink flowers droop in sorrow towards the parched ground.

Lesser Celandine (Ranunculus ficaria) - growing where recently bramble dominated

As I descend away from the splash of gold and skirt along the base of the cliff a movement to the right catches my eye and I see a basking Adder (Vipera berus) slide towards a clump of long grass with a small hole at its side. As I slowly crouch towards it and rest stone-still, the snake pauses and I am granted a view of the black arrowhead behind its red eyes.

Adders emerge from their underground hibernacula - often a mouse-hole they entered in October-time - at any time from late March or when daytime temperatures climb into double figures. Early mornings and late afternoons are the best times to search for them, when they bask in a sheltered spot, such as this, flattening their bodies against the warm earth, soaking up the sun's energy. This is an essential habit which aids hunting and digestion, especially early and late in the season. The immature male Adder before me will spend the next few weeks feeding mainly on mice or small reptiles such as lizards and slow worms. He'll take all the sun he can find.

This Adder might be the same individual we observed last year. He is not fully grown and I estimate that he is somewhere between two and three years old. Maturity is not reached until four or five years. Adders are fairly slow-growing snakes. He is possibly not mature enough to engage in the violent mating rite sometimes called the dance of the adders, which occurs in April or May. This is a wrestling match fought between males, in which no use of the fangs is made, and in which the winner may mate entwined with a female in a tangle with up to several other males.

Vipera berus - a basking female Adder

Adders are not the indiscriminate biters that some people hold them to be. They are misunderstood and vulnerable, unnecessarily persecuted by humans and predated upon by a number of animals including hedgehogs, birds of prey and crows - including the Jackdaws around the corner of this headland. Their venom is precious to them and they bite only if they are forced to defend. I have given this snake no reason to be fearful and he has paused and rewarded my cautious approach with the gift of a close observation. I back away and leave him to the sun.

The Jackdaws wheel and chatter above me and I return to my car, leaving the birds, bees, Adders and flowers to enjoy the sheltered sunlight.

Back into the Motherlode

A rich seam of hibernating moths and butterflies runs beneath the wintry land at Newhaven Fort and its stunning and embracing neighbour, Castle Hill Local Nature Reserve. They stand together, arm in arm, overlooking the Ouse estaury and facing the full force of the bracing English Channel winter. The historic tunnels are dark, damp, ventilated, mild and these conditions are stable. The temperature within the tunnels is consistently between 1°C and 2°C warmer than the ambient outside temperature. Any adult insect seeking an hibernaculum would increase their chances of surviving the winter as they fly into the tunnel entrances or ventilation shafts here. Buried alive each autumn to be reborn the following spring. We ventured into the dark, damp shafts twice during the 2015/2016 winter. This was the second winter of what we hope will be regular annual surveys. This is an account of what we found.

Outside and in: inside the southern counterscarp gallery

Outside and in: outside - the area close to the southern counterscarp gallery

Our first survey during this winter was made on 15th December 2015. The outside world was halfway through experiencing the warmest December on record and I was interested to learn whether the mild conditions had affected the number of hibernating insects within the tunnels. It had not; we saw very nearly the same number of insects as we had during the previous December. So does day length rather than temperature drive adults into hibernation, or is there a complicated juxtaposition between the two? All good tunnel surveys should generate more questions than you begin with - it's part of the journey.

Two new species were added to our list: Acrolepia autumnitella (Bittersweet Smudge) and Amblyptilia acanthadactyla (Beautiful Plume). Acrolepia autumnitella feeds as a caterpillar on bittersweet or deadly nightshade. The tiny caterpillar feeds within the leaves and creates characteristic pale blotches. As an adult, it remains small at about 6mm long, but its inconspicuous appearence is betrayed under magnification, revealing a macroscopic beauty in its brindled patches and pale cross-lines. There are two broods in most years, in July and again in October, when the adults hibernate and emerge the following spring to produce the next summer brood - exactly what our individual was doing. Photographs and further information about this and all the species described below can be found by following the links.

The Beautiful Plume (Amblyptilia acanthadactyla) is a common but spectacular little moth, which appears to have become more common during recent decades. It feeds in its early stage on a range of herbaceous plants and, similar to autumnitella, the adult flies in July and again in September, when it seeks hibernation.

Although total numbers were similar to those in 2014, there was an interesting variation in the numbers of individual species. The Bloxworth Snout (Hypena obsitalis) was present in almost the same numbers (thirteen this year; fourteen in 2014), as were Small Tortoiseshells (Aglais urticae), with six counted both this year and last. The Twenty-plumed Moth (Alucita hexadactyla) was more numerous with 47 seen this year compared with 32 last December. This intriguing little moth somehow chooses a resting place which, despite the pitch dark, often provides a cryptic background, for example a pebble-dashed wall. This makes it a challenging species to count with a headlamp, but perhaps the greater number seen this year suggests we have got our eye in better than we had during our first visit last year.

The Peacock (Aglais io) was seen in fewer numbers this year than last

The greatest contrast in numbers was seen in the Peacock (Aglais io). In 2014 we counted 33 individuals; this year we saw only twelve - nearly two-thirds less. Perhaps this was because fewer adults had survived this year to the point of hibernation? Perhaps last year's number will prove to be unusually high? More questions requiring an answer! Jean Jacques Rousseau once wrote that patience is bitter, but its fruit is sweet. This I am learning. We saw a total on ten species and 112 individuals during this survey, which has proved to be our best result to date, but only just greater than the very similar result obtained in 2014 (eight species, 109 individuals).

Curled autumn leaf: The Herald (Scoliopteryx libatrix)

Our second and final visit of this winter was made on Tuesday 2nd February. Why do we survey twice each winter? I don't know whether there is any value in this just yet, and a good enough reason might emerge during the coming years. For now, a second survey enables an interesting comparison with the earlier winter survey - a before and after or early- and late-winter evaluation. One clear benefit of a second visit is that it fulfils a need which grows within me during a long period which is otherwise absent of moths and butterflies. So the flame of personal gratification is perhaps the strongest attractant. But there is also a fascination that many of the individuals discovered during December have not move a single millimetre during the five or so weeks between our visits. There is a pattern emerging to this: certain species appear to enter a deeper slumber than others. For example, the butterflies - those poster boys of hot summer days - are regularly found in the same state in February as they were in December. The same may be said of the stunning Herald (Scoliopteryx libatrix), which hangs like a curled autumn leaf from the tunnel walls. Also apparently less active is the tiny micro-moth Digitivalva pulicariae (Fleabane Smudge), which inexplicably appears to seek the same section of deep tunnel a long way from the outside world and in which no other moth or butterfly species has so far been found.

A reluctant slumber? The Bloxworth Snout (Hypena obsitalis)

More active is the Twenty-plumed Moth, which will often flutter back into activity under torchlight. But by far the most restless species is the one we are the most interested in: the Bloxworth Snout. During the four surveys we have performed, the Bloxworths have proven to be sensitive to light, taking to flight as torchlight falls upon them and flying a short distance before settling down again. In February 2015 we counted only five of the fourteen individuals we had seen during our first visit in December. It seemed a fair suggestion that they were more tolerant than other species of cooler temperatures - a behaviour which is often witnessed in the outside world during the early and late winter, when they are seen around doorways - and that the Bloxworths emerge from a comparatively lighter slumber ahead of some other overwintering species. Does this convey some ecological or evolutionary advantage? Would this winter's second survey suggest the same behaviour? As well as one stand-alone survey could suggest this, yes it did: only seven of the thirteen individuals counted in December remained and the others were not seen. Of the ten species seen on 2nd February, only the similarly active Twenty-plumed Moth was seen in noticeably fewer numbers: 28 individuals compared with 47 seen in December. The numbers of both these species had roughly halved. Only patterns which emerge in future tunnel surveys will provide more robust data to these initial findings, but it is one of the more interesting findings we have made to date. Until December, patience.

One of the Bloxworth Snouts seen in February 2016

Another of the Bloxworth Snouts seen in February 2016

 

The Herald (Scoliopteryx libatrix) - a spectacular moth which is associated with Poplar and Willow

  

Overwintering insects in Newhaven

One of the surveyed areas at Newhaven Fort

There are not many places on this Earth where I have been buried alive and yet at the same time been able to see the far horizon. The tunnels at Newhaven Fort are one such place. On 17th December I had the privilege of accompanying underground the Custodian of Newhaven Fort, Steve Watkins, Lewes District Council Rangers Dan Fagan and Thyone Outram and Tony Hutson from the Sussex Bat Group. The purpose was to survey the accessible areas for hibernating bats and Lepidoptera. Along the way we saw only two Brown Long-eared Bats (Plecotus auritus), plenty of spiders, including many Amaurobius (probably fenestralis) which were active in the shady, damp, mild habitat. I didn't attempt to identify the spiders, but I was able to record a pleasing total of 110 moths and butterflies.

Two butterfly species were seen: Small Tortoiseshell (Aglais urticae) (6) and Peacock (Inachis io) (33) - two of which are pictured above. Six moth species were seen:

Case-bearing Clothes Moth (Tinea pellionella)  8 larvae
Fleabane Smudge (Digitivalva pulicariae) 3

Common Flat-body (Agonopterix heracliana)  5
Twenty-plume Moth (Alucita hexadactyla)  32
Herald (Scoliopteryx libatrix)  9
Bloxworth Snout (Hypena obsitalis)  14

This initial survey is hoped to be the first of a regular annual survey and some interesting data was collected to compare with what we see during future visits. The Case-bearing Clothes Moth (Tinea pellionella) larvae (pictured right) were, like most of the invertebrates we saw, close to the entrance and exit of a tunnel. They are likely to be feeding on natural fibres from rabbits or possibly birds nests, of which there are plenty of both within a short distance of where we saw them.

The only species we saw which was deep within a tunnel was Digitivalva pulicariae - the Fleabane Smudge (pictured below), and the three we saw were close together in a location which was roughly beneath the moat adjacent to the main car park. It is likely that they fed during their larval life stage on hemp agrimony (Eupatorium cannabinum), which has a fairly dense population on the adjacent Castle Hill Local Nature Reserve. How and why did they retreat to such an inaccessible part of the tunnels?

Fleabane Smudge (Digitivalva pulicariae)

Common Flat-body (Agonopterix heracliana) and Twenty-plume Moth (Alucita hexadactyla) are both very well known to hibernate overwinter as adults and to emerge when the day length and temperature increases the following spring. Both species have visited my moth trap on warm winter nights. It was no surprise to find these species within the tunnels, nor The Herald (Scoliopteryx libatrix) - one of the better known hibernators which, in its mimicry of a curled autumn leaf, could easily be mistaken or altogether missed.

Twenty-plume Moth (Alucita hexadactyla)

The Herald (Scoliopteryx libatrix)

Each of these species was a welcome sight during the lean winter months, but the value of this survey, the benefit of having made the effort to survey the tunnels, was seen in the fourteen Bloxworth Snouts (Hypena obsitalis) that we counted. This is a remarkable number.

The Bloxworth Snout in Sussex

Back in November, when the Newhaven Oleander Hawk-moth was making headlines, following its discovery by Steve Watkins and his colleagues, we (Thyone and me) had seen two Bloxworth Snout in the entrance tunnel to the Fort - the same location as the Oleander . They were at rest on the wall, a male and female. I suggested that the tunnels might offer a suitable hibernaculum for the species and, although we had previously decided that we should survey the tunnels, we made this species our main subject of interest. We were well rewarded. I would first like to place this in context.

I saw my first Bloxworth Snout in March 2010. It was an adult which had emerged from hibernation in the basement car park at Southover House in Lewes. It fluttered into my face as I walked out of the door, but came to rest for me to identify from a photograph I was able to snap.

Since 2010 I have seen it as a singleton on a further three occasions: at home in November 2012, when I saw one at rest outside of my kitchen door, at home again in July 2014 (an example of a second brood emergence?) and then up at the Fort in November 2014.

Using Colin Pratt's Complete History of the Butterflies and Moths of Sussex (2010) as a reference, the Bloxworth Snout was first recorded in Sussex in 1983 - in a garage at Houghton Green near Rye. One further 20th century record was made in 1997 at Littlehampton. A further five records were made between 2000 and 2009 before my moth flew into my face in Lewes. That adds up to a total of eight moths seen up to 2010. These records have led Colin Pratt to surmise that the moth, previously considered to be a scarce immigrant from continental Europe, was resident in the county by the turn of the century, if not before. All these sightings were singletons.

Between 2010 and 2013 the moth was recorded a further twelve times. Again, each of these reported sightings were of single specimens. This means that a total of twenty Bloxworth Snouts had been recorded in Sussex throughout its entire history in the county to the end of 2013. The brace that Thyone and I saw on 26th November this year was, it seems, the first recorded occurrence of two individuals in the same place at the same time.

The species is clearly becoming more widespread and a more regular visitor to Sussex-based Lepidopterists. This brings us up to date and the available data (excluding any records made during 2014) suggests that the species has a strengthening toe-hold along the Sussex coast. This was the situation as we entered the tunnels on 17th December: a total of 22 known adults previously recorded in the county.

This background helps to place the fourteen specimens we saw in the tunnels into context. It is a significant record which hints at the actual number of adults which may be present elsewhere in the tunnels at Newhaven and indeed along the Sussex coast. It is difficult to estimate how many of the fourteen moths were immigrants, but it is reasonable to suggest that most, if not all, are native to the cliffs at Newhaven, where they would have fed as larvae on either pellitory-of-the-wall (Parietaria judaica) or other Urticaceae species such as nettles. For those who are interested in climate change and the impact upon invertebrate species, the Bloxworth Snout would be a fascinating species to study and I suspect it will be recorded more frequently and in increasing numbers in the future.

I don't have that much data for records outside of Sussex, but I am currently aware that only Guernsey has returned greater numbers of the Bloxworth Snout, where the species is regularly seen in and around fortifications similar to those on the cliffs at Newhaven. I would strongly encourage the reader to seek out and survey any tunnels that you may gain safe access to, particularly in a coastal situation, in order to add to the knowledge of the Bloxworth Snout and other hibernating species. I will look forward to continuing this work in Newhaven - and I would happily join you elsewhere if you would like the company!

Many of the moths and butterflies seen were at rest near vertical shafts close to the open air, like this Bloxworth Snout

Castle Hill LNR, Newhaven: transect walk, week 24

Friday 12th September 2014 - a lovely afternoon spent walking along the transect route. Sunny (90%), warm (20°C), a bit of an easterly breeze but very warm in the more sheltered spots. Crickets and grasshoppers were buzzing in the grass and scrub, shieldbugs basking in the sun - but if you are looking at those then you are not focusing on the butterflies and moths!

Peacock (Inachis io)

White Bryony (Bryonia dioica)

Coreus marginatus Dock Bug

 

Field Bindweed (Convolvulus arvensis)

Honeysuckle (Lonicera periclymenum) berries

 

Butterflies (12 species, 330 adults)
Clouded Yellow (Colias croceus)  9
Large White (Pieris brassicae)  59
Small White (Pieris rapae)  190
Green-veined White (Pieris napi)  3
Small Copper (Lycaena phlaeas)  5
Common Blue (Polyommatus icarus)  14
Red Admiral (Vanessa atalanta)  8
Peacock (Inachis io)  5
Speckled Wood (Pararge aegeria)  26
Wall (Lasiommata megera)  4
Meadow Brown (Maniola jurtina)  3
Small Heath (Coenonympha pamphilus)  4

Moths (6 species, 27 adults)

Elbow-stripe Grass-veneer (Agriphila geniculea)  22
Yellow Belle (Semiaspilates ochrearia)  2
Vapourer (Orgyia antiqua)  1
Brown-tail (Euproctis chrysorrhoea)  216 larval webs
Ruby Tiger (Phragmatobia fuliginosa)  1
Silver Y (Autographa gamma)  1

Sphaerophoria scripta hoverfly

Other observations
The area of vegetated shingle to the west of the slumps beneath the cliffs is becoming more established. I wonder whether this will develop to emulate the flora along the coast at Shoreham Beach?

The area of vegetated shingle looking east and west below the cliffs, plus Sea Rocket (Cakile maritima).