Zennor to St Ives coastal walk
  1. Start by catching the bus from Trenwith Bridge in St Ives (turn left out of the car park, follow the road to the double roundabout and turn left to walk uphill to reach the bus stop just after the 2nd roundabout). Depart at the Zennor Turn bus stop and walk a few paces back along the road to the turning to Zennor. Follow the single track road towards the church until it ends in a T-junction.

    The name Zennor comes from St Senara, to whom the church is dedicated. There were no roads to Zennor until the 1800s so goods were brought here on sledges pulled by animals.

  2. Turn right at the junction and pass Bos Cres then turn left down the track marked "Coast Path". Follow this until it ends, with a small path leading ahead.

    The church building dates from Norman times, though the churchyard itself may date back further. The west tower is thought to be from the 13th century and the north aisle was added in a 15th Century rebuild. Only two of the 15th Century carved bench ends remain and these have been used to make the "mermaid chair", one end of which depicts the Mermaid of Zennor. It is thought that the octagonal font is mediaeval, and may date from the 13th century.

  3. Follow the path ahead to a stone stile.

    The twin promontories of Zennor Head are along the coast path to your right and the long, thin headland behind the headland on the left is Gurnard's Head, due to its profile being similar to that of the fish.

  4. Cross the stile to reach a sign for Zennor Head where the path meets the coast path. Keep right to join the coast path and follow it around the headland and behind Porthzennor Cove until it eventually ends via a few steps at a T-junction with another path at a granite waymark.

    As you follow the path from Porthzennor Cove to the junction, notice how the stones on the path change from hard fine-grained rocks to coarse-grained granite and the path starts to get gritty from weathered granite. The huge blob of granite that makes up most of West Penwith starts here, but didn't quite make it as far as Zennor Head. However, the heat from the molten magma, that eventually cooled to form the granite, altered the surrounding rocks.

  5. When you reach the junction, turn left and follow the coast path around the bay to the headland and to the back of the next bay until you reach a stone stile, just after waymarks.

    In this area, magma was forced under high pressure between the surrounding rocks which created granite sheets, visible as light-coloured bands in the darker rocks. You can see these in the rocks on the point that you cross over before you reach Wicca Pool, where the main mass of granite meets the sea. At low tide, rows of granite blocks can be seen in the channels between the grey rocks which would have originally been a single tendril of granite that later cracked.

  6. Cross the stile and stream and follow the path until you eventually reach a stone stile.

    The dandelion-like flowers along the coast are most likely to be catsear, also known as false dandelion. Catsear is very salt tolerant, not only growing along the coast but actually in sand dunes. The easiest way to recognise it is by the hairy leaves, hence the name. If you can cope with the texture, the leaves are edible and are much less bitter than dandelion leaves.

    Another way to tell them apart is when they are flowering. Although dandelion flowers over quite a long period, the most profuse flowering is in April and May whereas catsear's intense flowering period is in late June and through July. Catsear has neater flowers than dandelion with squarer edges to the petals (but still toothed). The stems supporting the flowers are also solid, in contrast with the hollow stem of the dandelion.

    Along the coast, from June onwards but particularly in the late summer and autumn, parasol mushrooms are common. They are one of the easier mushrooms to recognise due to their huge size (and umbrella shape when fully open). The brown flecks on their otherwise white flesh are caused by the rapidly expanding young mushroom bursting through a brown outer coating as it grows (a bit like "sugar puffs" breakfast cereal!). Other characteristic features include a snakeskin-like brown pattern on the stem and there's often a ring around the stem which is detached (can be carefully slid upwards to verify).

    Parasol mushrooms have firm white flesh and delicate flavour which is not strongly "mushroomy". This makes them an excellent carrier for other flavours within a sauce, adding texture and body to a dish.

    The word granite comes from the Latin granum (a grain), in reference to its coarse-grained structure. Granite forms from a big blob of magma (known as a pluton) which intrudes into the existing rocks. The huge mass of molten rock stores an enormous amount of heat so the magma cools very slowly below the surface of the Earth, allowing plenty of time for large crystals to form.

  7. Cross the stile and follow the coast path until you reach another stone stile.

    Heather plants have a symbiotic relationship with fungi which grows inside and between some of the plant root cells. Up to 80% of the root structure can be made up of fungi. The fungi are able to extract nutrients from poor, acidic soils that plants struggle with. In return, the plant is able to generate other nutrients (e.g. sugars by photosynthesis) that are useful to the fungi. A similar partnership between plants and fungi occurs in lichens.

    In July 1916 a huge area of fog caused problems for shipping all along the North Cornish coast. The Neto - a 3000 ton steamship on its way to Cherbourg carrying hay and fodder for the British cavalry horses - ran aground on Gurnard's Head and was wrecked. As salvage work began, another large cargo ship - the Enrico Parodi - laden with coal, appeared from the fog and ran aground just 300 metres away on the Carracks Reef. The salvage crews immediately switched their attention to saving the Enrico Parodi as only the bow was grounded and there seemed a good chance of floating her off at high tide. However as they attempted to tow her off using a salvage ship, a minor leak in the bow split open and the ship began to sink rapidly. The ship was quickly abandoned and sank in the deep water off The Carracks.

  8. Cross the stile and follow the coast path until you reach a pedestrian gate.

    The rocky islands off the point are known as The Carracks.

    The Carracks are named after the Cornish word for "rock". The largest island in the group is sometimes known as "Seal Island" due to the grey seals that live there, and boat trips from St Ives can be seen visiting the island to see the seals. The group of smaller islands closer to St Ives are now known as The Little Carracks, but in the early 20th Century they were still known as Carrack-an-Heythen which is from the Cornish meaning "rock of the birds".

    The rocks on the point surround a rocky lagoon that is isolated from the sea at low tide. The kelp beds surrounding the rocks provide shelter for small pollack which can be seen quite easily from the rocks when the sea is calm.

    The Cornwall Seal Group Research Trust gather information about the numbers of seals in each location to study migration behaviour. Each seal has a unique pattern of spots which is like a fingerprint, allowing individuals to be identified so photos are also very useful.

    If you see one or more seals, take a photo if possible but never approach the seals to take a photo - use a zoom from a clifftop. Send the location, date, number of seals and photos if you have them to sightings@cornwallsealgroup.co.uk.

  9. Go through the gate and follow the path until you reach a granite waymark with three yellow arrows.

    Gannets are the largest sea birds in the North Atlantic with a wingspan of up to 2 metres and are easily recognisable by their long white wings with black tips. Gannets can dive from up to 30 metres, achieving speeds of up to 100kph as they strike the water, enabling them to catch fish much deeper than most seabirds. To achieve this they have air sacs in their face and chest, which act as cushioning when they hit the water. Also they have no external nostrils, instead they are situated inside the mouth.

  10. Keep left to continue on the coast path and reach another junction of paths.

    The mermaid of Zennor is a Cornish folk tale, recorded in the 1870s. The story is of a beautiful and richly-dressed woman who occasionally attended services at St. Senara's Church and enchanted parishioners with her beauty and her voice, though they were intrigued that she never seemed to age over the many years she was seen. The mysterious woman became interested in a young man named Mathey Trewella - the best singer in the parish, and one day he followed her home and the two disappeared. Neither was seen again until a boat was anchored near Pendour Cove and a mermaid appeared, asking the crew to lift the anchor as its fluke was resting on her door and she could not reach her children. The crew recognised the mermaid as the mysterious woman who had sung at the church.

    The story is thought to have been inspired by the carved bench end in the church, rather than the other way around (some versions of the legend say that the church carving was created to celebrate the mermaid).

    More about the Mermaid chair.

    Stories of mythical half-woman half-fish creatures date back over 3000 years to Ancient Assyria and Greece and have been part of English culture for over 1000 years. The word "mermaid" comes from the old English word mere, meaning sea. Before the mid-19th Century, dugongs and manatees were routinely referred to as mermaids by mariners although in Cornwall, the most likely creature to be attributed to being a mermaid is a seal. The U.S. National Ocean Service felt it necessary to state in 2012 that no evidence of mermaids has ever been found.

  11. Turn left and follow the path downhill through a gate and down some steps to a footbridge. Cross the footbridge and walk a few paces to reach another junction of paths. Keep right and follow the path uphill to reach a trig point.

    The name "chough" is from the bird's call although this is not that accurate as "chough" is more like the sound a jackdaw makes (a very short "chu"). Locally, choughs were known as "chaws" which is a better representation of their (much longer) sound.

    The old Cornish name for the bird is Palores, meaning digger, which is thought to be a description of it rooting for invertebrates.

    The scientific name (Pyrrhocorax pyrrhocorax) means "fire crow" which is likely to be an allusion to its red bill and legs. This possibly also relates to the birds' mischievous reputation during the Tudor and Elizabethan periods for stealing lighted candles or embers and dropping these onto roofs, which were generally thatched in Cornwall at this time.

  12. Continue on the coast path to reach a junction of paths with a waymark post on the right.

    The process of placing trig points on top of prominent hills and mountains began in 1935 to assist in the retriangulation of Great Britain - a project to improve the accuracy of maps which took three decades.

    A plate (known as a "flush bracket" and marked with an ID code) on the side of each trig point marked a known measured height above sea level. The brass plate on the top with three arms and central depression (known as a "spider") was used to mount a theodolite which was used to measure the angles between neighbouring trig points very accurately. These angles allowed the construction of a system of triangles which covered the entire country and provided a measurement system accurate to around 20 metres.

  13. Bear left and follow the path along the coast to reach a metal kissing gate.

    Known as the "Merry Harvesters", the stone circle beside the Coast Path is reported as being fairly recently constructed to resemble one of the ancient stone circles, although many of the ancient circles were themselves reconstructed in Victorian times: The Merry Maidens near Lamorna Cove even gained an extra Maiden during its Victorian reconstruction.

  14. Go through the gate and turn right to follow the well-worn path. Stay on the main path (ignoring paths leading onto the headland on the left) to reach a wooden gate across the path.

    The northwest-facing coastline of Penwith was particularly treacherous for shipping. The high cliffs along the coast prevented ships from being able to see the lighthouses at Trevose Head or the Longships. From Cape Cornwall, the wall of granite runs towards the rocks of the Wra, or Three Stone Oar, off Pendeen, some of which are just below the surface. The cliffs continue all the way to St Ives, and part-way along is the protruding Gurnard's Head which was another major hazard for shipping.

  15. Go through the gate and follow the path along the coast until you pass beside a towering rock outcrop and reach another gate. Go through this and walk a short distance to reach a fork in the path with a waymark.

    If you encounter what looks like a small snake on the coast path with a golden-coloured stripe along the length of its back, it's a slow worm.

    During the summer months, slow worms can sometimes be seen basking in the sunshine, particularly on pieces of stone which act as a sunbed. Being reptiles, they don't generate their own body heat so they need to get it from an external source. Despite their resemblance to snakes, slow worms are lizards that have evolved to lose their legs. They are a good example of convergent evolution, where quite unrelated groups of animals have evolved to fill a similar niche. Slow worms are surprisingly long lived, and may exceed 30 years of age in the wild and over 50 years in captivity.

    Sea foam (also known as "spume") is formed due to organic compounds known as surfactants present in seawater. Under turbulent conditions, the surfactants form persistent bubbles which float to the surface, stick to each other through surface tension and are driven onshore by the wind. The surfactant compounds themselves arise from processes such as the offshore breakdown of algal blooms.

    On beaches, sea foam can conceal deep pools and gullies with an apparently flat, uniform surface. Tread carefully, especially on beaches you don't know well, to avoid walking off the edge of a precipice or vanishing into icy cold water.

  16. At the fork, bear left down the outer path and follow this around the headland until you reach a fork in the path where a tiny stream crosses the path.

    The foundations of an engine house are all that remains of the mine buildings which were once on Hor Point. The mine worked a copper lode which is exposed on both sides of the headland.

  17. At the fork, bear left towards the rock outcrop and follow the path to a pedestrian gate.

    At Hor Point, a radar station was built during the Second World War to monitor shipping and low-flying aircraft. The stations required the antennae to be swung back and forth to detect reflected signals. These were originally powered by members of the Women's Auxiliary Airforce mounted on wheel-less bicycles which chains attached to a gear system, but were later replaced by electric motors. After the war, in 1945, the radar station was disposed of using explosives, reducing it to rubble which rolled down the hill. Chunks of the debris are still on the coast path and in the undergrowth above it.

  18. Go through the gate and continue until you reach a grassy area just after the rocky causeway ends.
  19. In the grassy area, bear left to follow the main path over one low wall and continue to reach a second low wall.

    St Ives has a reputation amongst artists for its light. As well as the more obvious reflections from the sea, the north-facing aspect also has a bearing on this.

    To see a rainbow it must be sunny behind you and raining in front of you. As sunlight passes through raindrops, some is reflected back to you. Since in Cornwall the equator is to the south then the place to see rainbows over the sea is on the north coast (especially in the mornings).

  20. Keep right after the wall to pass the rock outcrop. Once you cross the brow of the hill, bear left towards the rock platform and then make for the red lifesaving buoy beside the sea. Follow the path along the edge of the coast towards St Ives from the buoy to reach a waymarked kissing gate.

    The beach ahead is Porthmeor, which has a typically functional Cornish place name, meaning "big cove".

  21. Go through the gate and follow the path to the fence of the Bowling Club. Continue on the path around the bowling green until you reach a fork in the path just before the Bowling Club building.

    In January 1938, the SS Alba was on its way from Italy to Wales and sheltering from a gale but mistook the lights of Porthmeor for those of St Ives and ran aground. The St Ives lifeboat was launched and rescued 23 crew from the ship but then capsized and was washed onto the rocks. The lifeboat crew were all rescued but five of the Alba crew drowned. The boilers from the Alba can be seen on Porthmeor beach at low tide. Bomb disposal experts were acquainted with them in 2012 after they were mistaken for an unexploded sea mine by holidaymakers unfamiliar with Cornwall's metallic shoreline fixtures.

  22. Keep left to follow the path alongside the stone wall. Continue until this emerges onto the pavement of the road.

    The Holy Well of St Ia (Venton Ia in Cornish) is a spring located opposite Porthmeor Beach, below the churchyard. The spring has been incorporated into the stone walls that surround the cemetery and now consists of two recesses each containing a trough of water. The resulting frenzy of stonework has been described as not one of the prettiest holy wells in Cornwall, despite the effort that must have gone into it. A plaque states "The holy well of St Ia, until 1843, the main water supply to Downalong" (the name for this area of the town).

  23. Join the lane and follow it downhill, past The Tate, to reach a junction with a cobbled street.

    Porthmeor is the largest beach at St Ives, and consists of golden sand. There's a beach at all states of the tide although it's quite a narrow strip at high tide. The beach faces north into the Atlantic so it gets some reasonable surf.

    The name means "big cove" in Cornish. It is often referred to as "Porthmeor beach" and although the appended "beach" is technically redundant (given that the name already means "cove"), it does serve to distinguish it from Porthmeor Cove, not so far away along the coast near Morvah.

  24. Keep left at the junction in the direction signposted for St Ives Museum and then stay on the lane. Follow it around a bend to the right and along a short cobbled section to reach Quay Street near the pier.

    Smeaton's Pier was constructed towards the end of the 18th Century and was originally about half the current length, ending with the lighthouse. In the 1860s this was extended by adding a wooden pier (which was even longer than the current one) but this had collapsed within 20 years. The remains of the wooden supports can still be seen at the lowest point of the tide. Finally the stone pier was extended at the end of the 19th Century and the three arches were added so that sand could flush out from the harbour to prevent it silting up.

  25. Turn right onto Quay Street and follow this along the harbour to reach the Lifeboat Station.

    The Sloop Inn, which lies on the wharf, is dated to "circa 1312", which makes it one of the oldest inns in Cornwall. The building is likely to have been rebuilt a number of times over the centuries and the current structure is thought to date from the 17th-18th century. It is described by Lonely Planet as "a classic old fishermen's boozer, complete with low ceilings, tankards behind the bar and a comprehensive selection of Cornish ales."

  26. Continue ahead from the Lifeboat station on the path along the sea front to reach a lane beside St Ives Art Club.

    St Ives has had a lifeboat since 1840, though the original was a rowing boat launched from the harbour. In 1867, the RNLI relocated it to Porthgwidden beach and built a boathouse for it. This was not well thought out as launching through the surf proved near impossible and so it was quickly replaced by a building in Fore Street. In 1911, a new boathouse was built on the quay which was better suited to launching the lifeboat which had become motorised by this point. This was finally replaced with the station you see today which was built in 1993 to accommodate a larger modern boat.

  27. Turn right onto the lane and follow this to a crossroads. Cross the road opposite signposted to Visitor Information (Guildhall). Follow the lane past the Guildhall to a junction.

    During Victorian times, open air painting became popular and the scenery and mild climate of St Ives generated a reputation as the ideal place for marine painting (of the decorative rather than boat-keeping kind). Once the railway was completed in 1877, St Ives became more accessible. Around this time, the pilchard industry was in decline which resulted in many unoccupied net lofts, cellars and workshops. These became converted into artists studios, with the first recorded in 1885 which had been converted from a sail loft. In 1920, Bernard Leach arrived and went on to make St Ives internationally famous through his pottery. St Ives has continued to attract artists and is now considered to be one of the most important art centres in Britain. In 1993, the St Ives branch of the Tate Gallery opened (named after the sugar magnate Henry Tate of Tate and Lyle). Since 1978, there has been a St Ives September Festival which runs for 15 days during which many artists open their studios to the public.

  28. Bear left across the road at the junction to the small lane to the left of the building opposite with lanes either side. Follow this until you reach a concrete ramp on the left.

    Barbara Hepworth moved to Cornwall at the outbreak of WW2 in 1939 and was part of the St. Ives School of Painting. She is famous for her abstract sculptures, which often featured simple, geometric forms and was a close friend of abstract sculptor Henry Moore. She died in a fire in her studio in 1975 thought to be caused by smoking in bed.

  29. Bear left up the path alongside the ramp and climb the flights of steps to emerge on a residential road.

    There are several reasons why seagulls should not be fed.

    One is that human foods are not nutritionally suitable for seagulls but seagulls are not smart enough to know these can damage their health.

    Another is that seagulls become dependent on humans and lose the skills to obtain food from natural sources.

    The reason most affecting us is that feeding seagulls makes them less scared of humans. Since seagulls do not have have the emotional wiring to empathise with humans, fear is the only thing preventing that interaction being aggressive. Seagulls are innately aggressive when it comes to food as their behaviour with other seagulls demonstrates. There are many examples of children being attacked (who then drop food, reinforcing the behaviour).

  30. When you reach the top of the steps, turn right onto the road and follow it until you reach a car park on the left with a path signposted to Trenwith car park.

    The extra distance covered by going up and down also adds to the distance shown on a map. However, despite your legs telling you otherwise, this is actually not that huge either. There are two parts to it:

    On an exceptionally arduous walk solely on the coast with lots of deep valleys, the distance travelled "up and down" is likely to be at most about 10% compared to the distance on the flat. For a more normal coastal circular walk the "up and down" distance is typically not much more than 5% of the distance on a flat map.

    The second consideration was worked out by Pythagoras. The shallower the incline, the less significant the elevation adds to the overall route distance. Even with an average gradient of 1 in 3 (which is insanely steep), you're looking at only around 10% of the total elevation distance being adding onto the route length.

    So since the elevation distance itself is already a small percentage of the route length (5-10%), the small "pythagoras" percentage (less than 10%) of the already small elevation percentage is not much more than a gnat's whisker.

  31. Bear left up the path to the Trenwith car park and follow it until you reach a signpost for Leach Pottery.

    Bernard Leach is considered one of the pioneers of the studio pottery movement. After learning ceramic skills in Japan, he set up a pottery in St Ives in 1920. Bricks salvaged from the National Explosives Works at Upton Towans were used for the first kilns and rhododendrons growing near the Steeple were harvested as fuel. Clay from the pits at St Erth was used for some of the pottery. Leach wrote several books on pottery and was influential in promoting the Japanese pottery tradition in the West. In 2008 Leach Pottery was restored and reopened as a museum to celebrate his work and legacy.

  32. Turn left up the small path beside the signpost to reach the pedestrian crossing to the car park.

    The large car park in St Ives was once the site of Wheal Trenwith which was mainly a copper mine, although a small amount of tin ore was also extracted. Amongst the copper ore was a black crusty ore that miners thought was copper oxide, but smelting it proved unsuccessful so it was discarded on the waste tips. It was identified as pitchblende (a Uranium ore, containing other radioactive decay products of Uranium-238) but it was seen of no value. An account from 1843 states:

    Pitch-blende occurs in great abundance among the copper ores of Wheal Trenwith, and was long carefully collected, and thought to be black copper ore. The low prices obtained for the ores with which it was mixed, and the inferiority of the metal they yielded, equally disappointed the miner and the copper-smelter; until a specimen of the copper was examined by Mr. Michell of Calenick, and found mixed with uranium in a metallic state. The ores were then inspected, and pitch-blende being discovered among them, its nature and prejudice to the copper ores were explained to the workmen, by whom it has been, of course, since rejected. Was there ever an instance in which an acquaintance with Mineralogy and Chemistry would have been more useful ?

    By 1907, the economic value of radium was well understood and waste tips were being worked for this valuable ore; small pockets were also extracted from the shallower areas of the mine. Between 1911-1917 there were 694 tonnes of uranium ore recovered, mainly from the waste tips. There are reports that pieces of the pitchblende ore can still be found around the edges of the car park today. It is radioactive so handling pieces of the black rock is not advised.

The Greater Black-backed Gull is the largest member of the gull family and a bird of formidable size, with a wingspan of nearly 6ft. Unlike other gulls, the Greater Black-backed Gull is highly predatory. Young birds are a significant portion of its diet and it tends to live amongst other seabirds where it can eat the neighbours. It has also been known to swallow whole rabbits and even eat young lambs. It often steals food from other seabirds using its large size to intimidate them into dropping it, and consequently it is sometimes referred to as a pirate.

The large black birds nesting on offshore rocks, known colloquially as the cormorant and shag, are two birds of the same family and to the untrained eye look pretty similar. The origin of the name "shag" is a crest that this species has on top of its head and the cormorant doesn't. The cormorant is the larger of the two birds with a whiter throat. The shag's throat is yellow, and mature shags have a metallic green sheen on their feathers which cormorants lack.

The fulmar is a grey and white bird related to an Albatross although it can be mistaken at a distance for a gull. Close up, the beak is the giveaway: the fulmar has a tube on its beak which is visible as a black bar across the beak at a distance. The tube is a gland for excreting salt from the seawater that they drink. As a defence mechanism, the fulmar regurgitates foul smelling oil from its stomach - the name comes from the Old Norse for "foul" (full) and "gull" (mar). The oil disrupts the waterproofing of predatory birds' feathers in a similar way to a crude-oil spill, so they avoid preying on fulmars.

Clapper bridges are an ancient form of bridge built out of stone slabs spanning piers in the river. Most were built during mediaeval times, often beside a ford where horses and carts would cross. There is disagreement over the origin of the word "clapper". One candidate is an Anglo-Saxon word cleaca meaning "a bridge of stepping stones". Another is a mediaeval Latin word clapus which is is thought to have originated in Celtic Western Europe and to mean "pile of stones".

Ravens are the largest member of the crow family and have a bigger wingspan than a buzzard. They are most easily distinguished from other members of the crow family by their very large black beak which has a hooked top. Other members of the crow family have straighter beaks. Their call is a deep croak.

During Victorian times, ravens were exterminated by farmers and gamekeepers throughout much of the UK but retained a stronghold in the southwest. Their nests, constructed of robust twigs, can be seen along the cliffs in Cornwall.

Researchers have found that ravens use gestures to communicate in a similar way to humans. Obviously ravens don't have hands so instead they point with their beaks to indicate an object to another bird, just as we do with our fingers. They also hold up an object in their beak to get another bird's attention.

Scientists have found that ravens will console a friend after it has had an aggressive encounter with another bird. This is good evidence for empathy i.e. the birds are able to determine emotional needs of other birds and respond to them.

Bracken is a type of fern. Perhaps the easiest way to spot mature bracken plants is by their sturdy stem which acts a bit like the trunk of a tree with leaves going out horizontally from this. Other ferns leaves tend to grow directly out of the ground. Earlier in the year, bracken is recognisable by the fronds emerging from the ground singly rather than grouped in tufts.

Although the fronds of bracken die back each year, the black underground roots are perennial and spread extensively, sending up fronds at intervals. The root system of one bracken plant can stretch up to a quarter of a mile across making bracken one of the largest plants in the world.

Fossil records indicate that bracken dates back at least 55 million years. By 24 million years ago it had a worldwide distribution and it is now thought to be the most common plant in the world.

Bracken is both poisonous and carcinogenic to many grazing animals which will avoid it if at all possible. Eating bracken is not recommended as it is thought that the carcinogenic properties may also apply to humans based on the circumstantial evidence that Japan, where young bracken fronds are a delicacy, has the highest levels of stomach cancer in the world.

Bracken releases toxins into the soil which inhibit the growth of other plants, and the shade created by its large leaves and its thick leaf litter also makes it hard for other plants to compete. This and avoidance by grazing animals makes it quite difficult to control, particularly in steep areas where mechanised cutting or ploughing is difficult. Treading by livestock can reduce bracken's competitive advantage, particularly during winter when frost can attack the roots.

In woodland, the Victorians used a horse-drawn roller to control bracken. The hollow roller was made from a frame of iron bars which crush bracken stems but allow springy tree saplings to ping back. This horse-drawn method still survives in Cornwall and is sometimes hired by the National Trust for their woodlands.

Bracken has been used as a fuel for centuries but is of interest as a modern biofuel due to its very high calorific value. Normal firewood produces around 15-19 gigajoules of heat per tonne of material (depending on moisture content - drier is more efficient hence kiln-dried logs). Elephant grass can produce around 18 GJ/t and bracken can deliver 21 GJ/t. At least one company has piloted creating compressed fuel briquettes from bracken in a similar way to elephant grass.

Stonechats are robin-sized birds with a black head and orange breast that are common along the Cornish coast all year round.

The name "stonechat" comes from the sound of their call which resembles stones being knocked together.

During the summer months, stonechats eat invertebrates. As temperatures drop and there are not so many of these about, they make do with seeds and fruit such as blackberries. Quite a few die in cold winters but this is offset by their fast breeding rate during the warmer months.

A similar-looking bird called the whinchat is also present in the summer but this can be identified by a white stripe across its eye. Both stonechats and whinchats can often be spotted perching on dead sticks or brambles protruding above gorse and heather, and consequently the term "gorse chat" or "furze chat" has been used locally to mean either species. For a long time, stonechats and whinchats were thought to be members of the thrush family but genetic studies have revealed they are actually members of the (Old World) flycatcher family.

From geography lessons at secondary school, you'll probably know that wave-cut platforms form where waves hit the cliff face and create a wave-cut notch into which the cliffs above eventually collapse. The reason the cliffs are eroded faster than the platform below them is more in the realms of physics:

Nevertheless, the platform does slowly erode. At Porthleven it is estimated that the platform is eroding at a rate of 1mm every 5 years.

Granite formed as a molten blob of rock beneath the surface, underneath millions of tons of other rock. As the granite cooled, it cracked, mostly vertically due to the pressure from above. Hot water circulated through the cracks, reacting chemically with the rocks and depositing minerals. Over millions of years, the softer rocks above were eroded and the pressure from the weight of the rock above was released, causing horizontal cracking in the granite. The result is cubic blocks where the rough edges have been gradually smoothed by weathering.

Both Common Dolphins and Bottle-nosed Dolphins are quite frequently encountered off Cornwall. Bottle-nosed Dolphins are the species found in marine parks and are the saloon car of the dolphin world: quite large (adults are 7-12ft long), plain grey and tend to cruise at fairly low speeds though they can do short bursts of over 30km/h. Common Dolphins are their sports car cousins: a little smaller (adults are 6-8ft long) with a flashy hourglass-shaped "go faster" stripe of gold at the front and light grey at the back and can swim up to 60km/h. The considerable intelligence of dolphins includes the ability to learn new behaviours from each other and cooperate with other dolphins or even human fishermen to catch fish.

The herring gull is the gull most commonly encountered in Cornwall, with a grey back and red spot on their yellow beak. They live for around 12 years and are highly intelligent birds with strong communication and social learning skills. This has allowed them to evolve strategies to obtain food more easily by stealing it from humans, either when briefly left unattended or by swooping and grabbing from unsuspecting hands.

Whilst their pasty and ice cream stealing antics in coastal resorts might give the impression there are lots around, the coastal herring gull population dropped by about 50% from 1970 to the mid 1980s and the decline has continued with another drop of around 50% up to 2020.

Part of the decline in coastal herring gull populations can be explained by a migration of birds inland to urban areas. Birds have been driven inland in search of food and roosting sites due to declining fish populations and lack of undisturbed coastal nesting sites. In urban areas, streetlights allow gulls to forage by night and there is no longer much competition from red kites, which scavenged the rubbish tips in the Middle Ages.

At the time of writing, a survey of the inland populations is being carried out to determine the relative size of these vs the coastal population and if these are stable. The first datasets from some of the devolved UK Nations suggest that is unlikely to explain the majority of the decline. Since the 1990s, 96% of the population in Northern Ireland died out predominantly from botulism. It's thought that birds seeking food on rubbish tips might be bringing this back to colonies.

The herring gull is an example of a "ring species". In Europe, the lesser black-backed gull and herring gull are distinct species, yet as you circumnavigate the globe, the populations become more similar until they merge in the middle as a single species.

Herring gulls are able to communicate nuances both by altering the frequency and timbre of their calls - conveying, for example, the relative severity of a threat in an alarm call. They also analyse and remember the personality of their neighbours, ignoring more skittish birds but taking action when a more trusted bird raises an alarm.

According to "The Z to Z of Great Britain", there are just over 40 place names in Britain that begin with the letter Z; over three-quarters of them are in Cornwall. One of the main reasons for this is that the Cornish word for "coastal inlet" is zawn, and coastline is something that Cornwall has rather a lot of.