Moths in special habitats: Sea-cliffs and Headlands

In this article, we will look in detail at the some of the more remote, rugged and wild habitats around Britain's coastline. The Ordnance Survey of Great Britain estimates that the mainland, together with all of the smaller islands, has a coastline of 19,490 miles! A large proportion of this is cliff or rocky in nature and its grand scale represents an immense amount of available habitat for all forms of wildlife. Britain's coastal cliffs are equally blessed with complex geology, giving rise to multi-layered, vertical life zones. Climate and vegetation constantly change along the coast from county to county, as do some of our most specialised resident moths. The fact that most cliffs and headlands are facing out to sea also means that biological degradation brought on by excessive use of pesticides and fertilisers, and so often blamed for the downturn of inland invertebrate populations, has little or no effect here.

Sea-cliffs and headland at South Stack RSPB (Anglesey), June 2011 (Roger Wasley).

There are many other reasons why coastal cliffs and rocks are so good for moths. The coastal climate tends to be much more constant than that experienced inland, which means that a whole range of specialised wild food plants can thrive. The general inaccessibility of the habitats to grazing animals and humans means that these are not eaten or cut down. There are many places such as caves, crevices and recesses where eggs, small larvae, pupae and hibernating adults can shelter during the winter storms. Natural erosion and cliff fall can provide new bare areas, where colonising plants form an important part of the early succession and give some of our scarcer host-specific moth species a chance to spread onto new ground. It is essential to ensure that these natural processes continue and to make sure that freshwater springs flow normally to avoid long-term changes in hydrology.

Devonshire Wainscot in Glamorgan, a characteristic species of the rocky coastlines of southwest England and south Wales (Barry Stewart).

Some of the most important moth food plants that are found at these habitats are Rock Sea-spurry, Sea Campion, Sea Plantain, Thrift, various vetches and Wild Cabbage amongst the rocks, with Holm Oak and various grasses along the cliff top. Many of the moth life stages are seemingly faced with potential natural hazards such as high tides, land-slips, storms, salt spray and so on, but appear to survive well in what, to man, is a dangerous environment.

The best sea-cliffs and headlands for moths tend to be found in the south and west where the climate is milder. Some of the Hebridean islands are also good, no doubt due to the effect of the Gulf Stream. Certain sites and areas have a proven track record for seeing good moths and these include:

• Abbot's Cliff and adjacent Folkestone Warren LNR (Kent)
• Durlston CP (Dorset)
• Portland (Dorset)
• The western Jurassic Coast of Dorset either side of Charmouth
• Prawle Point (Devon)
• The Lizard (Cornwall)
• Hartland Point (Devon)
• Hurlstone Point (Somerset)
• The Gower (Glamorgan)
• Pembrokeshire coast
• South Stack RSPB (Anglesey)
• The Ballycotton area (Co Cork)

Prawle Point (Paul Bryant).

Hartland Point (Devon) (Paul Bryant).

Apart from the resident species, sea-cliffs and headlands are also good places for incoming migrants, which we will cover in a forthcoming article. Some very large sites such as Folkestone Warren LNR have extensive areas of accessible under-cliff, as well as steep chalk cliff accessible by steep zigzag footpaths. These various sections all have their own micro-climate and harbour different moths, so considerable effort may be needed to see the various specialities. Perhaps the most important consideration when thinking of light trapping at these sorts of locations is safety. Try to place moth traps on open flat areas adjacent to well-marked footpaths. Wait for a calm night; moths will be difficult to attract if it is blowing a gale. Coastal moths are quite mobile and traps set around the edge of car parks will often produce the same results as those placed in more precipitous situations. Try to set up equipment before dusk and leave overnight rather than packing away in potentially dangerous conditions in the dark. Most of the best coastal headlands and cliffs will be accessible from car parks and coastal footpaths managed by the National Trust, various heritage trusts or local councils, so always make sure you obtain permission from the landowners if thinking of doing a nocturnal moth survey at any site. It is also a good idea to inform the local coastguard of your intention to run bright lights at open or exposed coastal sites.

The following guide is a basic reference to the times of the year the moths are at large, and further research must also be done as to find out exactly where they are found. Most of the species should be covered by the various major reference books such as Waring and Townsend. Individual county publications and websites are other sources of information. Some species can be looked for during the day. The Chalk Carpet can be found sparingly around the English coast in July and August where suitable chalk cliffs are to be found. It can be easily disturbed and followed up on accessible slips and under-cliffs. The Bloxworth Snout has an interesting lifestyle with one long overwintering brood and another shorter mid-summer brood, and can be found at any time roosting in caves, man-made structures and small holes in stone walls. The Thrift Clearwing can be seen around west Cornwall, west Pembrokeshire and on Anglesey. Because of its tiny size and fast flight it is best looked for with the aid of a special "hyl" pheromone lure. Place this amongst cliff-top Thrift flowers on sunny afternoons in June or July.

Thrift Clearwing, Anglesey, June 2011 (Roger Wasley).

Habitat for Thrift Clearwing at South Stack RSPB (Anglesey) (Roger Wasley).

It is worth waiting until June before targeting coastal cliffs and headlands. Species that emerge during the second half of May remain on the wing and are soon joined by many others. It may also be early summer before the weather improves enough for a prolonged nocturnal visit. Galium Carpet, Lesser Treble-bar, Netted Pug and Cream-spot Tiger are soon supported by Mullein Wave, Portland Ribbon Wave, Valerian Pug, Thyme Pug, Brussels Lace and Dew Moth.

Mullein Wave, Kent, 2011 (Steve Whitehouse).

A trip to the Gower or west Pembrokeshire headlands in June can provide Pod Lover and Barrett's Marbled Coronet. The later species can also be looked for at Hartland Point and Prawle Point (both Devon).

Pod Lover, Pembrokeshire (Mike Pritchard).

More resourceful moth-ers taking a mid-June excursion across the Irish Sea to the rugged Cork coastline near Ballycotton can add both Bordered Gothic and the Grey to the two just mentioned above. The Bordered Gothic is now considered extinct in the East Anglian Brecks and although still rumoured to be on Portland (Dorset) there are no confirmed records there for over a decade. Morris's Wainscot can be looked for at dusk at damp land-slips along the western Jurassic Coast of Dorset in late June.

Bordered Gothic, Co. Cork (Matthew Deans).

Hoary Footman, Annulet and Brown-tail emerge in early July together with Crescent Dart, Northern Rustic, L-album Wainscot and White-lined Dart.

Northern Rustic, Co. Clare (Steve Whitehouse).

L-album Wainscot, Dorset (Steve Whitehouse).

Later in July Marbled Green, the Confused, Devonshire Wainscot and Rosy Minor make their appearance.

Marbled Green, Suffolk (Matthew Deans).

Confused (Steve Whitehouse).

Any serious moth-er will, at some stage in their career, find a trip to Hartland Point (Devon) in mid- to late August absolutely essential. With luck, Hoary Footman, Square-spot Dart, Black-banded, Devonshire Wainscot and Scarce Blackneck will all come to light and some of these can also be found nectaring on cliff-top flowers just after dusk.

Steep scree slope and cliff-top habitat at Hartland Point (Devon) (Paul Bryant).

Black-banded, Devon (Paul Bryant).

Scarce Blackneck, Devon (Paul Bryant).

A similar trip timed a month later to the Isle of Portland (Dorset), specifically the slightly less spectacular but equally productive disused quarry adjacent to Cheyne Weares car park, will give the visitor ample chance to observe Feathered Ranunculus, Beautiful Gothic and Feathered Brindle. Great care must be taken when descending from the cliff-top path down to the flat quarry bottom south of the car park, especially if carrying electrical equipment. Once set up, the quarry walls give virtually all-round protection from the wind. This site is also very good for migrants and micro-moths at any time of the year.

Cheyne Weares quarry, Portland (Dorset) (Paul Bryant).

Feathered Ranunculus, Kent (Paul Trodd).

Beautiful Gothic, Dorset (Steve Whitehouse).

Still in Dorset, a late-September or early-October night at the famous Durlston Country Park just south of Swanage can — with the right weather conditions — be a memorable experience. All of the Portland specialities can be expected, albeit perhaps in smaller numbers, and there is the added bonus of the two classic Holm Oak feeders: Oak Rustic and the recently established Sombre Brocade. Another recent colonist, the Clancy's Rustic, is now quite regular in traps into October and the awesome Brindled Ochre can also be seen before winter hibernation. Durlston also has a fine track record for rare and wonderful southern migrants. Always contact the visitor centre staff in advance, advising of your intentions, and always let them have a full species list the morning after if possible. You can contact them via their website.

The lighthouse gully at Durlston CP (Dorset) just before dusk (Steve Whitehouse).

Sombre Brocade, Dorset (John Chaimey).

Clancy's Rustic, Hants (Simon Wright).

Brindled Ochre, Dorset (Steve Whitehouse).

There are many other hundreds of miles of coast to explore. Many places will be under-recorded so there are always chances of discovering something new, either at county or national level. It is very important to let individual county moth recorders have a complete record of what you find. And remember always think 'safety' and enjoy.