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.
Tors started out as a lump of granite beneath the surface, which cracked vertically into squares and then part-way through horizontally to form something resembling a stuck-together stack of square pancakes. Millions of years of weathering then gradually rounded these off and widened the cracks between the layers to result in a more burger-like appearance.
In some cases the horizontal cracks didn't go all the way through so the layers are still joined (the skewer through the brioche bun to stretch the burger analogy to its limit). In the cases where they did fully separate, a massive rocking stone such as the famous Logan Rock at Treen could be created, or the whole lot could collapse into a pile of huge rocks.
The "basins" on the tops of some of the tors are also the result of repeated freezing and thawing of water which has collected on the surface.
The word is from the Celtic language but is likely to have come from the Latin turris, meaning "tower", derived from a similar word in Ancient Greek.
The summit of Helman Tor is enclosed by the stony banks and walls of a Neolithic Tor Enclosure. Excavations have revealed evidence of occupation, including houses, pottery and stone tools carbon-dated to the Early Neolithic.
A stone axe was found in 1971 on the flanks of the tor. It was given to the Royal Cornwall Museum who examined the greenstone it is made from and concluded that it's likely to have originated from Mount's Bay. This gives some suggestion of the trading taking place in Early Neolithic times. Clay from the pottery sherds on the site has also been found to be made from "gabbroic" rocks which only occur in the St Keverne area within Cornwall, suggesting a trade in pottery. This is also supported by finds of "gabbroic" pottery at other Neolithic sites such as Carn Brea.
Gorse is also known (particularly in the Westcountry) as furze from the Middle English word furs. This itself is from the Old English word fyres, closely related to the Old English word for fire.
Like sloes and damsons, bullaces are a member of the plum family and may originally be native to Great Britain. The fruits resemble sloes but are a bit larger and bullace trees are not so thorny as blackthorn. Despite being a distinct species from sloes, the name is from the Old French for sloe - beloce. The Cornish dialect name is bullum tree.
The taste of bullaces is astringent like sloes when unripe but when fully ripe (quite late in the autumn) some are just about sweet enough to eat raw. As with sloes, freezing them (traditionally the first frost in the days before freezers) makes them less bitter. They are typically used in cooking to make jams or for fruit wines where their tannin content makes the wines age well. They will also do just as well as sloes for flavouring gin.
The taller trees along the road are oak.
The older an oak tree becomes, the more acorns it produces. A 70-80 year old tree can produce thousands. Acorns are high in carbohydrates and as well as being a staple food for squirrels, they are also a really important food for deer and make up a quarter of their diet in the autumn.
The (leather) "tanning" process got its name as it involved extracting the tannins from acorns or oak bark and soaking these into animal hides over 1-2 years to preserve them. From the brown oak juice containing the tannins, the colour "tan" was named and from this the expression "sun tan" arose.
Cornwall Wildlife Trust was founded in 1962 as the Cornwall Naturalists' Trust and was run entirely by volunteers until 1974. It was renamed in 1994 as part of a national initiative to unify the names of wildlife trusts across the country. It now manages over 50 nature reserves and has over 17,000 members with over 1,000 active volunteers.
There's a volunteering section on the Cornwall Wildlife Trust website which includes lots of marine activities as well as things in the nature reserves.
Wetlands act as sponges, storing and gradually releasing water which helps to prevent floods and buffer river levels during dry periods. Sediment and nutrients washed off the land by rainwater are absorbed by the wetland plants, feeding the wetland ecosystem but also filtering and cleaning the water before it enters rivers.
The magpie is believed to be one of the most intelligent of all animals. The area of its brain used for higher cognitive function is approximately the same in its relative size as in chimpanzees and humans. Magpies can count, imitate human voices, recognise themselves in a mirror and have been observed regularly using tools to keep their cages clean. It has even been suggested that magpies may feel complex emotions, including grief.
A tributary of the River Par flows along the edge of Red Moor and tin-bearing gravels were deposited which became buried under the topsoil. This had been discovered by the Early Mediaeval period and the gravel was mined for tin until the 19th Century. As well as the valuable tin oxide (which is typically black), the gravel also contained some iron. When this comes into contact with air and water, rust-coloured iron hydroxides are formed which colour the lakes and this is thought to have given rise to the name of the moor.
Catkins begin to form on hazel trees from November onwards and in February these reach full size and flower before the leaves appear. The word is from the Dutch katteken (meaning "kitten") as the catkins resemble small cats' tails.
Hazelnuts can be found beneath the trees in September and October and are a favourite with squirrels so you'll need to forage those that haven't already been nibbled. Once harvested, the nuts need to be dried before shelling and eating. Wash and dry the nuts first to reduce the chance of them going mouldy. Then lay them out on something where the air can circulate and dry them for 2-4 weeks. An airing cupboard is a good place. You can tell that they are ready when the nuts rattle in their shells. Once shelled, the nuts can be stored in a fridge or even frozen for a couple of years.
Hazel is one of the smaller native trees, reaching only 20ft. When allowed to mature, the tree lives for about 70 years.
The Ramblers Association and National Farmers Union suggest some "dos and don'ts" for walkers which we've collated with some info from the local Countryside Access Team.
Do
Don't
The lakes are the remains of the Wheal Prosper tin streamworks.
The first method to extract tin was known as "tin streaming" which reached its peak in the 12th Century, though continued until the mid 20th Century.
Alluvial deposits occurred where a river had eroded the tiny crystals out of mineral veins. Due to tin being so heavy, the crystals had become concentrated on the bottom of the stream as the lighter rocks around them were washed away. Over time these deposits were buried in gravel and sand, and eventually soil.
Using quite elaborate banks and channels, the river was diverted to wash away the soil and gravel, leaving the heavy tin-rich rocks behind which could be dug out once the river was diverted away.
One side-effect of all this industry was that the topsoil, sand and gravel washed downriver caused the silting of many river estuaries and once-thriving mediaeval river ports literally dried up and were superseded by sea ports.
Once the relatively rich alluvial deposits had been used up, mostly by the 18th Century, mineral veins were instead mined directly.
The common earthball is a woodland fungus that looks a bit like a scaly white or pale yellow potato and its external appearance could be confused with a small puffball fungus.
Earthballs have a slightly different approach to release their spores than puffballs. When mature, puffballs have a central opening in the top through which the spores puff out. With the earthball, the surface of the cap ruptures when the spores are ready to release.
Since puffballs are edible and earthballs are poisonous, it is a common offender for stomach upsets arising from misidentification. This might seem strange as puffball flesh is pure white whereas the internal earthball flesh is dark (purple/brown/black) when mature. The potential for confusion arises because when very young, the earthball flesh is pale.
Cuckoos are migratory birds that overwinter in Africa and are first seen, or more often heard, in Cornwall during the spring. The cuckoo is well-known for laying its eggs in the nests of other bird species. The adult cuckoo is a mimic of a sparrowhawk - a predator; this causes other birds to abandon their nests, allowing the female lay her eggs. Although cuckoo eggs are larger than those already in the nest, cuckoos produce eggs in several different colour schemes to match those of several species of bird. Since the cuckoo chick is a much larger than even the full-grown foster parents (which they seem not to notice, assuming their offspring is just a bit portly), it needs to monopolise the food supply. It therefore methodically evicts all other eggs and chicks from the nest.
The information board mentions that the hazel in the woods is coppiced.
Coppicing is a traditional form of wood production that became redundant when industrial sawmills could easily cut full-grown trees into a range of timber sizes.
The approach with coppicing is, rather than simply planting trees and letting them grow to full size, that the trees are grown only until the trunks are suitable for use as poles and then they are cut to the ground and allowed to regrow.
The cycle produces varied habitats of clearings, bushes and small trees which each support different types of wildlife. Coppicing has therefore been reintroduced in many places as part of a conservation woodland management scheme to promote biodiversity.
Sphagnum (peat) mosses use compressed air to launch their spores. To get an idea of the acceleration that the spores are launched with, an astronaut in a rocket launch experiences an acceleration g-force of about 3 g and the maximum in a fighter jet is about 9 g. Sphagnum moss spores are accelerated at 36,000 g!
By using their tail as a parachute, squirrels are able to survive falls from high trees. This allows them to attempt risky jumps between treetops that don't always work out. They are one of the few mammals that can (but not always) survive an impact at their terminal velocity i.e. if a squirrel jumped out of an aeroplane, it may well survive.
Bracket fungi are one of the most important groups of fungi responsible for wood decay. This is good for nutrient cycling but less good if you own a forestry plantation. Many bracket fungi begin on living trees and can eventually kill a branch or whole tree by damaging the heartwood and allowing rot to set in. They can continue to live on the dead wood afterwards and a much more diverse range of species of bracket fungi are found in old natural forests with lots of dead wood.
Devil's bit scabious can easily be confused with sheep bit, so much so that sheep's bit is sometimes called "sheep's bit scabious", despite not being a member of the scabious family. Both plants have blue pom-pom-like flowers and although sheep's bit has its main flowering period in May and June before devil's bit gets going, their flowering periods do overlap in the late summer. Devil's bit is usually a taller plant and has pink-purple anthers protruding above the blue flowers. It also has quite big leaves whereas sheep's bit leaves are small and hairy.
The name "devil's bit" has come from the Middle English develesbite although the thinking behind the mediaeval name is not completely obvious. According to folklore, it's from the short black root, bitten off by the devil in a sulk. The scabious family of plants are said to be named for their treatment of skin ailments so "devil's bite" could have been a name for a particular condition.
The jay is a member of the crow family recognisable by the flash of electric blue on their otherwise brown body. Their natural habitat is woodland, particularly oak.
Like squirrels, jays collect and bury acorns as a winter food store. Once jays were the main means by which oaks colonised new locations as a population of 65 jays can bury (but not always find again afterwards) half a million acorns in a month. Jays prefer to bury their acorns in open ground which is an ideal spot for a new oak tree.
The field is grazed by a lot of rabbits as well as some cattle.
If a rabbit is placed on its back and its legs are stroked, it appears to go into a relaxed trance and many owners of pet rabbits thought this was a cute thing to do that was enjoyable for the rabbit. It's now understood that this reaction, known as "tonic immobility", occurs when the rabbit is extremely stressed because it thinks it is about to be eaten by a predator! It is effectively a "playing dead" reaction to lull a predator into a false sense of security so the rabbit can make a sudden escape when the predator isn't paying attention.
Field mushrooms are very closely related to the familiar supermarket button mushrooms and are the most commonly-eaten wild mushroom in Britain. They usually appear in grazed fields between July and November but can be out as early as May. They can sometimes be seen growing in a ring. The gills start out pink and become brown with age and the cap is slightly downy, especially around the edges, often with a skirt left on the stem. As there are a few species of white mushroom that all look quite similar, care needs to be taken to avoid eating poisonous species.
In particular, the common but poisonous "yellow stainer" looks very similar to a field mushroom and consequently causes the most mushroom poisonings in Britain. If the flesh is of a yellow stainer is cut or bruised, particularly at the base of the stem, a yellow liquid starts to seep out (unless the mushroom is very dried-out). This can take a few minutes to be apparent so it might not be until you get them home that you notice yellow patches where the caps have rubbed against something. The yellow stainer also has an unpleasant "chemical" smell (sometimes described as an "elastoplast smell") which helps distinguish it from the more appealing "mushroomy" smell of a field mushroom. A small minority of people have been reported as suffering no obvious ill effects from (presumably accidentally) eating yellow stainers but for the vast majority of people they cause stomach upsets which can be fairly severe including cramps, projectile voting and diarrhoea.
A pair of buzzards have a territory which includes a number of possible nesting sites which can be as many as 20. They move nesting site each year which prevents a buildup of nest parasites such as bird fleas. The new nest is decorated with fresh green foliage.
The Saints' Way runs for 30 miles from Padstow to Fowey, and follows one of the likely routes of early Christian travellers making their way from Wales and Ireland to the Continent during the Dark Ages. Rather than risk a premature martyring on the rocks around Land's End, they would disembark their ships on the North Devon and Cornish coast and cross the peninsula, on foot, to ports on the south coast such as Fowey. The Bush Inn at Morwenstow is thought to be one of the stopovers from the North Devon ports. The route from Padstow to Fowey was in use before the Dark Ages which is evident from Roman coins found along the route. However it is thought that it was likely to have been in use even earlier still, in the Iron Age.
The buzzard family is quite closely related to hawks and consists of a number of different species which occupy different habitat niches (e.g. colder countries further north). The buzzard species we see in the UK is the common buzzard. This is one of the largest birds of prey in Britain with a wingspan of over 4 feet.
The name buzzard is from mediaeval English buisart which itself came from the Old French word buson. It is based on the Latin word for hawk or falcon buteo hence its scientific name is Buteo buteo.
Buzzards are not quiet birds! Their long, loud "pieeuuu" call can be often be the first thing to give away their presence and is one of the easiest bird calls to remember. It is thought that the original Latin word for buzzard was probably an onomatopoeia (i.e. an imitation of the bird's call) within the constraints of what was deemed an acceptable Latin word (suggesting "pieeuuu" would probably have resulted in being fed to the lions!).
Buzzards were once thought to be a threat to game birds and were actively shot. During the 1950s-60s, the combination of myxomatosis nearly wiping out one of their main food sources and use of pesticides such as DDT caused further decline in the buzzard population. Since then the population has gradually recovered and buzzards are now the commonest and most widespread bird of prey in the UK.
A large proportion of buzzards diet is earthworms and carrion and consequently they have a reputation for being lazy and scavengers. However, when they need to be, buzzards are formidable predators. Diving on rabbits and small mammals from a slow or hovering flight, or from a perch, they nearly always make the kill on the ground.
In a natural habitat, buzzards perch at the top of trees to survey the surrounding fields. Their brown-and-white pattern camouflages them quite well so it's quite common for walkers to inadvertently disturb what turns out to be a huge flapping monster just feet away. Telegraph poles provide a perfect alternative to trees without any cluttering branches so buzzards can often be seen perched on the top, unfazed by cars passing beneath.
Buzzards breed once they reach 2-3 years old. During their breeding season in spring, male buzzards create spectacular aerial displays to impress females by soaring high into the air and dropping suddenly towards the ground. The birds then pair for life.
A pair of buzzards have a territory which includes a number of possible nesting sites which can be as many as 20. They move nesting site each year which prevents a buildup of nest parasites such as bird fleas. The new nest is decorated with fresh green foliage.
Biologically, there is no such thing as "toads": there are just many species of frog, some of which were given the name "toad" if they were a bit drier- or wartier- looking. However, the 2 species of frog known as the "Common Frog" and "Common Toad" are those you are most likely to encounter in Cornwall, so for discerning fairytale princesses, here's how to tell them apart:
Newts are members of the salamander family, which dates back to the Jurassic period. The newt species you are most likely to encounter in Cornwall is the palmate newt. Great crested newts aren't found in Cornwall at all. Common newts, contrary to their name, were only ever found in the far east of Cornwall and have become rarer over time. In recent years, the newt population has declined in the UK overall due to pollution and destruction of their habitat. Old farm ponds with good weed cover make good habitats as newts prefer still water to fast-flowing streams.
The name "newt" is actually from a mistake. The Old English word was ewt and so it should be "an ewt" but because this sounds the same as "a newt", ewts accidentally gained the "n" from "an".
Newts walk with a side-to-side gait by moving their front-left and back-right legs forward at the same time, followed by the other diagonal pair. This waddling form of motion is the origin of the phrase "pissed as a newt".
However, unlike drunk people, when injured, they have the remarkable ability to regrow limbs, eyes and even their heart! They are consequently of major interest to medical science.
The orchids are one of the largest families of plants with over 28,000 recorded species, many of which live in the tropics. It is thought that the first orchids evolved somewhere between 80 and 100 million years ago. The word "orchid" comes from the Greek word for testicle on account of the shape of the plant's tuber. Consequently, in mediaeval times, the plant was known as bollockwort.
Fungi are often most noticeable when fruiting, either as mushrooms or as moulds but their main part is a network made up of thin branching threads that can run through soil, leaf litter, wood and even living plant tissue.
Fungus is the Latin word for mushroom but is derived from the ancient Greek word for sponge since this is what they were thought to resemble. Biologically, this isn't so far off either as fungi are more closely-related to animals than plants.
95% of all plant life on Earth, including trees, relies on a symbiotic relationship with fungi. It is thought that without fungi, land plants could not have developed at all. Fungal mycelium often grows around or actually within the roots of plants and give the plant access to water and nutrients it couldn't otherwise obtain easily from the soil. In return, the plants provide the fungi with sugars produced through photosynthesis.
Pond skaters are able to stand on the surface of water due to long legs and water-repellent hairs on their feet.
The weight on each foot is less than the combined cohesive forces between water molecules ("surface tension") around it. Their long legs space out their feet so that the dents in the water's surface from each foot don't connect.
However, in order to walk on water, pond skaters must exert extra force to propel themselves which if applied to the surface of the water would sink them. The very tips of the water-repellent hairs on their feet penetrate the surface of the water and these create swirling vortices like tiny oars. The vortices transfer momentum down below the surface of the water so the surface of the water doesn't need to take all the force.
The little yellow flowers with four petals all over the moor in July are tormentil (Potentilla erecta). Its common names include Bloodroot and Flesh and Blood because roots yield a red dye which is still used as an ingredient for artists' colours (tormentil red). The roots also have very a high tannin content and have even been used to tan leather. Extracts from the plant have been widely used in folk medicine and is it still used as a remedy for diarrhoea and as a lotion for skin sores.
The salt-laden breeze coming off the sea dries out leaf buds and inhibits growth so the plants end up growing most vigorously in the lee of the wind. In the direction facing the prevailing wind, the growth is therefore more compact and stunted whereas in the lee of the wind, the branches are much more straggly. The result is that the trees appear to point away from the prevailing wind. Where there are no obstacles interfering with the wind direction, the shape of the trees can be used as a compass. Prevailing winds come from the southwest, so in general, trees in Cornwall point northeast.
Granite is the most common igneous rock found at Earth's surface and also the oldest - thought to be formed up to 300 million years ago.
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.
Granite mostly contains slightly acidic chemical compounds, and consequently there is nothing to neutralise acids arising from plant decay and carbon dioxide dissolved in rainwater, resulting in acidic moorland soils.
Granite is pretty hard stuff. It ranks at 7 out of 10 on the Mohs hardness scale. It's harder than normal steel but not quite as hard as hardened steel (which is 7-8). Cutting on granite worktops is therefore not a good idea as knife blades become blunt quickly.
Dragonflies were some of the first winged insects to evolve, around 300 million years ago in the "age of amphibians" before the dinosaurs. Fossils of early dragonflies have been found with wingspans of up to two feet across.
Dragonflies are named after the way they hunt, as both the larvae and adults are carnivorous predators. Mosquitoes form a large part of their diet both for adults and particularly for the larvae (nymphs). One dragonfly can eat tens of mosquitoes in a day and an average of over 100 per day has been recorded for the nymphs of some species. It is thought that this is an important factor in keeping the mosquito population under control. Dragonfly nymphs have a massive lower jaw to engulf their prey (a bit like an Angler Fish) and are also able to propel themselves by shooting a jet of water out of their anus.
Their two sets of wings beat out of phase, and the frequency, amplitude and the angles of each set of wings can be controlled. This allows dragonflies to hover in a completely stationary position for over a minute, perform extravagant aerobatic manoeuvres and even fly backwards.
Damselflies are predators similar to dragonflies but are easily distinguishable by the way their wings fold back parallel to the body when at rest whereas the dragonflies' wings are fixed at a right angle to the body. The Damselfly has a much smaller body than a dragonfly which means it has less stamina for flight. Nevertheless, it can hover, in a stationary position, long enough to pluck spiders from their webs.
Male damselflies have two sets of genitalia. At the start of mating a packet of sperm (spermatophore) is transferred outside of the male's body between the two and then passed on to the female who uses it to fertilise her eggs as she lays them. Female damselflies lay their eggs inside vegetation. For some species this is in water plants and the female can swim underwater for half an hour before returning to the surface to breathe. Males often guard the egg laying female to prevent a rival male from sneaking in and replacing the spermatophore with his own.
Damselfly eggs hatch not into damselflies but water-living nymphs which look a bit like a dull-coloured damselfly with a 3-forked tail instead of wings. The tail is actually a set of gills used to breath underwater. When the larva is fully developed, it climbs out of the water on a stem or rock. Its skin then splits open and a damselfly emerges with wings which need to be inflated and dry before it can fly.
Biologically, there is no clear distinction between ducks, geese and swans (geese and swans are one lanky subfamily of ducks). Dark-coloured ducks get the equivalent of "grey hairs" with age - their feathers gradually turn white.
The species of duck that you're most likely to encounter is the mallard. Mature males have striking iridescent green heads and dark bodies whilst females look totally different - a brown and white pattern which offers much better camouflage. However, both have a common feature that is unique to mallards - an iridescent blue patch on their wings.
In situations where ducks need to watch out for predators, they can sleep one half of their brain at a time, keeping one eye open for danger. In safer circumstances, ducks will sleep fully.
Male ducks (drakes) have a penis which falls off every autumn and regrows the following spring. The length each year depends on the amount of competition for females and varies up to a maximum of the duck's whole body length.
Ducks can change gender. This happens for about 1 duck in 10,000 and more commonly from female to male than the other way around. It seems to occur in a flock of ducks where there is a significant gender imbalance where it gives the duck that changes a competitive advantage. It's likely that the female to male direction is a bigger evolutionary win because one male can fertilise multiple females.
Feeding bread to ducks is quite bad for them although not feeding ducks anything at all is potentially worse as many have now become reliant on being fed. White bread lacks many of the nutrients that ducks need but ducks will gorge on it to the point of ignoring other foods, effectively becoming junk food addicts. The problem is that by filling up on just this, they can become malnourished, deformed and even die. Some healthier things to feed ducks are leftover peas, sweetcorn, seeds, rice and salad.
The word crow is from the Old English crawe. Since this sounds a lot like the noise the bird makes, there is a misconception that the Old English is directly derived from this. In fact the word is far older. It's related the the Old Saxon kraia and can be traced back further to a Proto-Indo-European word from the late Neolithic period which is thought to mean "to call hoarsely".
The word "crow" is sometimes used to refer to the whole crow family (including jackdaws, rooks and ravens) and sometimes specifically to the common (carrion) crow. Carrion crows can be distinguished from their cousins by being totally black (jackdaws have grey heads, rooks have pale beaks) and having a slender and fairly straight beak (i.e. not the broad beak with a hooked top that a raven has). Biologists use the word "corvids" for "crow family" to avoid ambiguity, or to show off.
The collective noun for a group of crows is a "murder". The term has been traced back to around the 15th Century, originally as a murthre (which was a Middle English word that meant "murder"). It is thought that the expression may be based on crows scavenging carcasses.
Birds of the crow family are considered to be among the world's most intelligent animals, displaying a high learning ability and are able to use logic for solving problems. Researchers have found some crow species capable of not only tool use but also tool construction. Crows have also demonstrated the ability to distinguish individual humans apart by recognising facial features. If a crow encounters a cruel human, it can also teach other crows how to identify that individual.
Research has shown that crows have a much higher density of neurons in their forebrains than primates do (the density of neurons in this region is thought to correlate with intelligence).
The brain of a crow accounts for 2.7 percent of the bird's overall weight whereas an adult human's brain represents 1.9 percent of their body weight. This is even more impressive when considered in context: birds need to be as light as possible in order to fly.
Ravens are considered the most intelligent crow species, outperforming chimpanzees in some tests. Consequently an academic is quoted as saying that crows are "smarter than many undergraduates, but probably not as smart as ravens."
Studies have shown that crows are capable of self-discipline. If offered one piece of food now or two later, the crows will resist temptation and wait. However if the initial piece of food is a high value item such as sausage, they won't take the risk.
Crows are omnivores and their ability to eat anything from animal feed to potato chips has allowed them to capitalise on food sources created by humans. Their problem-solving skills also allow them to access food that less savvy animals cannot, for example tugging on bin liners and tucking each fold under their feet to raise the contents of waste bins in motorway service stations.
Crows have a vocabulary of different calls with specific meanings and these can be varied to convey emotion like a human tone of voice.
The sounds that crows make have also been found to vary with location rather like regional accents in humans. When a crow moves into a new area, it mimics the calls of the most dominant flock members to fit in with its peer group.
There is a somewhat brutal rural tradition of hanging dead crows in fields with crops. Scientists now understand why this was so effective. Research has shown that crows understand the concept of death and can distinguish an (obviously) dead crow from a taxidermically-stuffed (alive-looking) crow. Crows often gather around a dead individual in "crow funerals" to try to determine the cause of death and assess the threat to themselves. They become wary of the place a dead crow is found but will also harass humans who handle crow corpses.
In the 3rd Century BC, the Romans named their ill-fated gangplank for boarding other ships "corvus" (Latin for crow) because its end contained a large metal spike which was thought to resemble a crow's beak. The end of the gangplank was dropped from a height onto the captured ship and the spike acted as a nail, attaching the gangplank to the deck of the ship being boarded. The design was short-lived because the 36ft gangplank sticking up from the front mast of the ship did nothing for its stability and consequently resulted in almost two entire fleets being lost in rough seas.
The hawthorn tree is most often found in hedgerows where it was used to create a barrier for livestock, and in fact haw was the Old English word for "hedge".
Hawthorn has many folk names which are spread across quite a diverse range of features. Names such as "maytree" or even just "may" are references to when it flowers. However "whitethorn" is not about the blossom but a reference to the lighter bark colour than blackthorn. The name "bread and cheese" derives from the very young leaves being edible. It is also sometimes called "thornapple" due to the apple-like shape of the fruits. This is not a coincidence as both the hawthorn and apple are members of the rose family.
There are two species of hawthorn found in the UK. Common hawthorn (also known as one-seed hawthorn) has a single seed in each berry. The other species - known as midland or woodland hawthorn - has two seeds per berry (and 2 stigmas in the flower rather than one). In Cornwall, the "midland" species is - as you might guess from the name - not that common.
As well as its thorns, another thing that makes hawthorn good for hedging is its very rapid rate of growth of around half a metre per year. Consequently one of the alternative common names for it is "quickthorn".
In sheltered places, hawthorn trees can reach 20-40ft in height and live up to 400 years. In harsher environments such as the coast and moors they can be as little as 5-6ft tall.
The flowers of the hawthorn are known as "May Blossom" and were traditionally used as decorations in May Day celebrations. Now, however, the hawthorn generally doesn't flower until the middle of May. The reason for this is that May has moved! Until 1752, Britain used the Julian Calendar which had leap years every 4 years but no other corrections. This results in a length of day that is fractionally too long, so the first of May gradually slipped forwards over the centuries. By the 1700s, the first of May was 11 days ahead of where it is today.
In Mediaeval times, bringing hawthorn blossom into the house was thought to bring death and it was described as smelling like the Great Plague. The explanation for this is thought to be that the hawthorn blossom contains trimethylamine which is one of the first chemicals formed when animal tissue decays. Young leaves of the plant can be used in salads as the chemical is not present in the leaves so these taste nutty rather than of death.
Hawthorn's red berries, also known as haws, are abundant in September and October. These are an important winter food for birds such as thrushes and small mammals such as dormice and wood mice.
Hawthorn berries have traditionally been used to make fruit jellies as they contain pectin and have an apple-like flavour. A reason for making seedless jellies is that the seeds in hawthorn berries contain a compound called amygdalin, which is cyanide bonded with sugar. In the gut this is converted to hydrogen cyanide.
The genus name for hawthorn - Crataegus - is derived from krátys the Greek word for "hard" or "strong". Hawthorn wood is fine-grained, dense and most definitely hard. It has traditionally been used for things that benefit from these properties such as wooden mallets, the teeth of rakes and cogs for mill wheels.
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.
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