The value of worms and a belted beauty

Athayde Tonhasca is a specialist adviser at Scottish Natural Heritage with a particular interest in invertebrates. Here he takes a look at some of the less glamorous species of the natural world – earthworms, and a rather curious moth.

In 1881, a few months before his death, Charles Darwin published his last book: The formation of vegetable mould, through the action of worms. The book was a huge success, selling 6000 copies in the first year; more than On the origin of species when it was first published. In the book’s final paragraph, Darwin said:

The plough is one of the most ancient and most valuable of mans (sic) inventions; but long before he existed the land was in fact regularly ploughed, and still continues to be thus ploughed by earth-worms. It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures.

To most people, Darwin’s work on earthworms was a revelation about the importance of these discreet and humble animals. And his enthusiasm was well-justified; because of their burrowing, mixing and fertilizing, earthworms are vital to the process of soil formation, and consequently vital to plants and every organism that depends on them.

Earthworms also help maintain the structure of our soils; their burrowing creates tunnels that channel air, water and nutrients into deep layers of the soil. These burrows loosen up the soil to facilitate penetration by roots, and reduce runoff, thus decreasing the rates of erosion.

Different species (there are 26 in the UK) can be divided into three groups, based on their ecology and behaviour:

  • Epigeic earthworms (epigeic: refers to an organism that is active above the soil surface, from epi, meaning ‘above’ and geic meaning ‘earth’). These species live among leaf litter on the soil surface and usually do not to make burrows. They play an important role in decomposing leaves and plant matter on the ground.
  • Endogeic earthworms (endogenic: related to the interior of the earth). These worms live and feed underground, making burrows parallel to the surface. They eat only buried organic material, such as dead plant roots. As they spend their lives unexposed to light, they lack skin pigments and are usually pink, gray or white.
  • Anecic earthworms: These are the deep-dwelling species, and the most familiar types. They make build vertical burrows that can reach several metres down, into which they drag plant and other plant matter to feed. The common earthworm is their best known representative and the largest British earthworm.

By eating soil, dung, plant litter and other materials (depending on the species), earthworms break down organic matter into smaller fragments, helping bacteria and fungi decompose them and release their nutrients.

Earthworms are able to process 2–20 tonnes of organic matter per hectare each year, a digested volume that ends up as castings (worm excrement). Darwin calculated that in 10 years, worm castings from an acre of soil (0.4 ha) would form a 5 cm-thick layer of top soil (what he called ‘vegetable mould’). Castings are rich in nitrogen, phosphorus, potassium, magnesium and calcium, all minerals essential for plant growth, and also contribute to the physical properties of the soil.

Common earthworm (c) Laurie Campbell

Common earthworm (c) Laurie Campbell

With their relentless activity, earthworms gradually deepen the topsoil layer, mix soil and organic matter, increase soils capacity to absorb and hold water, and increase its fertility. Essentially, earthworms change the earth. It’s no wonder that Darwin called them ‘nature’s ploughs’.

Earthworms are something most of us are more likely to see than the belted beauty moth, which recently caused a deal of interest at our Rum National Nature Reserve. The female is particularly interesting for being wingless: and the belted beauty is one of several moth species characterised by reduced wings (brachyptery) or no wings at all (aptery).

Belted beauty

Belted beauty

Insects appeared in the Early Ordovician period (~479 million years ago), but the explosion of diversity that made them the dominant creatures on Earth happened when they acquired the ability to fly, thus becoming capable of exploring a three-dimensional world.

From then on, insects could occupy diversified niches, disperse and search for food more efficiently. In fact, it is believed that wings have contributed more to the success of insects than any other feature.

This raises the question of why the belted beauty, and some other moths, were selected to lose their wings or the ability to fly. This is a question that has puzzled biologists since Charles Darwin mused over the problem.

The answer may be related to the huge energetic cost of flying; flight muscles comprise 10-20% of the insect’s body weight. If flying does not give the species significant advantages, the energy required to sustain it could be diverted to some other function – such as producing more eggs, for example.

In fact, flightless insects are most often found in stable habitats (where dispersal is not necessary for the survival of populations), isolated areas (such as montane and coastal strands), and in areas where a great amount of energy is required for flight (for example, cold regions or areas subject to strong winds).

Conservation of energy in cold environments and adaptation to strong winds seem plausible explanations for the loss of wings of female belted beauty moths, but we can’t know for sure. What we do know is that the species is perfectly adapted to its environment. Wherever it occurs in Scotland (the west coast, Hebrides, Mull, Iona, Colonsay and Islay), females crawl by the dozens at the top of fence-posts, to disperse pheromones into the wind and so attract mates.


Further reading :

OPAL, a citizen science initiative, is open to all of those who would like to record their sightings.  Find out more @ .

By taking part in the above survey, you’ll help improve our knowledge of earthworms and the soils they live in – something we still know surprisingly little about. There is also a chance to learn some fascinating facts … for example it is often a surprise for people to learn that a hand full of soil has gone many time over through the gut of earthworns – they are the soil engineering, essential to healthy soil structure and areation.

Find out more about International Year of Soils 2015 at

And read all about the magnificent Rum National Nature Reserve at


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Spring stories from Muir of Dinnet

Squirrels and slow worms have been amongst the highlights at our Muir of Dinnet National Nature Reserve lately, as Catriona Reid (the Reserve’s Manager) reports in this May update. Down by the water things have been stirring too, so, all in all, plenty of reasons to visit this fabulous nature reserve.

It is easy to understand why squirrels do well here. Most of this pinewood is naturally regenerated – these trees have seeded themselves, not been planted – and pinewoods are the stronghold of red squirrels. Interestingly red squirrels shed their ear tufts in summer- they’re probably at least, in part, there to help keep their ears warm over the winter. But none of our squirrels have shed theirs yet.

Lochnagar from the reserve

Down by the lochs, the common sandpipers continue to noisily defend their territories. In common with a lot of birds that spend a lot of time around water (like wagtails and dipper) they bob up and down a lot.


My colleague Paul also captured some gorgeous shots of a willow warbler. It had found a moth and was removing the wings before eating the nice, fat juicy body!  Meanwhile, the ducks are continuing to produce ducklings. We spotted a batch of newly-hatched ones on Parkin’s Moss. This has been a real success story for wildlife – the dams installed here over 15 years ago have now allowed the bog to become wet enough for ducks, as well as seven species of damsel and dragonfly to breed.

Willow warbler with moth

But the champion baby-producers right now are the geese. Over 58 goslings were on the loch this week. Here, the geese are forming them into a ‘crèche’, where a few broods young join together with their parents for protection. The partnership between the greylag and the barnacle goose has also survived! We have at least another  four greynalce (or barlag) crosses this year.

More baby geese - up to 58 fluffy and cute goslings on Loch Kinord now.
One species of reptile on the reserve has been showing well this week.  The grass cutting was somewhat delayed until we persuaded this slow worm to shift off the lawn. Fortunately it was a lot faster than normal but we still got a lovely view of it. You can see how much shinier and smoother they look compared to adders.

Up close- I'd get much closer to this guy than an adder!

How big is the slow worm? only about 10 inches!

And, if you’re at Burn o Vat, it’s worth checking out the wild cherry or gean tree just outside the centre- it’s beautiful just now!

Find our how to get to Muir of Dinnet NNR, and more about the reserve at


Gean blossom

Posted in Muir of Dinnet National Nature Reserve, National Nature Reserves | Tagged , , ,

Deer count from the air

Jamie Hammond is a Deer Management Officer for Scottish Natural Heritage. One of the more dramatic tasks he works on is helicopter-based census work. It’s a tried and trusted way to accurately count deer, and here he reveals a little of what is involved in a deer count exercise.

In early March 2015, ten staff and contractors from the Wildlife Operations unit carried out a helicopter count of deer in the Breadalbane area. This was part of our ongoing support to the Deer Management Group, and our aim was to provide high quality data on the local deer population which will subsequently inform management of deer in the area.

Three helicopters were used for two-and-a-half-days to cover the 90,000 hectares and a total of 9,330 red deer were counted.

Red deer stag

Red deer stag (Cervus elaphus)
©Peter Cairns/2020VISION

A huge amount of work goes into preparing for these counts. We work closely with the Deer Management Group and estate owners and staff to identify the area, fence lines, and boundaries over the area we will survey and who will participate. This then needs to match up with a suitable weather window – ideally with low winds, good visibility and snow cover and crucially helicopter availability.

Often this has to happen at short notice so all the planning needs to be in place well in advance. Crews need to be identified, accommodation booked, landing sites for the aircraft organised and fuel located on site.

To add a further challenge this time around BBC Scotland’s Landward crew also wanted to film us in operation, as part of a story on deer counting for the new Landward series. We were delighted to help them out so in this instance this was another element to factor in.

On the morning of Tuesday March 10 it was all systems go and over the next two days the count team worked hard to cover the area, photographing groups of deer, grid referencing them and recording information and cross checking. All the individuals involved were highly experience in this type of work and used to the somewhat challenging conditions in the helicopter due to the wind (it’s not easy counting whilst battling motion sickness!), tricky weather conditions and suitable light for taking photographs . We also had to ensure it was completed within budget in the short time window we had.

Red deer Hind and young calf   © Danny Green/2020VISION

Red deer Hind and young calf © Danny Green/2020VISION

On completion of the day itself there followed several weeks of data processing, quality control and assistance from our Geographic Information Group colleagues to create count maps. The field team then collate all the information together into a count report that is then shared with everyone in the Deer Management Group.

Why do we survey and what do we do with the information?  Well, the data is quite simply used to influence management decisions, allow estates to balance their sporting objectives whilst maintaining deer densities at levels where negative impacts to designated features are minimised.

So all in all it’s a big effort from a large team of people to ensure the job is well done and we get valuable information to inform future deer management issues.




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A new look for our oldest NNR

The sun was shining on Rob Gibson as he cut the ribbon to officially open the new facilities at Beinn Eighe and Loch Maree Islands National Nature Reserve on Saturday. Around 50,000 people who visit the UK’s oldest NNR each year can now benefit from a £330,000 restoration of its visitor centre, which was able to take place thanks to 45% EU funding.

Continue reading

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Words and outdoor worlds: nature writing at Moniack Mhor

Linda Cracknell is a writer of fiction and non-fiction with strong links to nature and landscape. Here she whets our senses with words for outdoor places.

Get someone to close their eyes and bury their hands and nose in a pile of last autumn’s rotting leaves. What does it prompt — memories? imagination? words?


Exploring the outdoor world can return us to childhood. Examining the creatures living in the sandy deposits of the burn we become playful, crouching children, marvelling as we poke at newts and caddis-fly larvae. Inhaling pine resin evokes for one person the memory of her grandmother’s wardrobe; for another, sweet cicely rubbed between fingers releases a scent-memory of liquorice sweets. At its best, writing feels like a kind of play too; diligent play. We arrange words to spark up images, sounds and stories, capturing them for ourselves and for others.


Moniack Mhor creative writing centre near Beauly is running a residential course designed to bring together these two kinds of play. The centre stands at about 300 metres, its gusty heights giving a commanding view into Stathfarrar’s hills and down to the green depths of Glen Convinth. But nearby are forests with mysterious corridors offering bright keyholes to loch and hill, and open moorland on a high brink above monster-deep Loch Ness. At this elevation there are surprises of chilblain and sunburn and green and the clatter of black-throated divers in a mating display. It all weaves a potent magic.


Senses are the foundation of sharp, observational writing and if we start with that pile of leaves it isn’t long before words are generated.

‘What does it smell like?’

‘Pungent, like my den in the woods when I was 10.’

‘Choose a verb for what the scent of the leaves is doing?’

‘Punging – is that a verb?’

It can be if you make it one. The rotting leaves are punging. Verbs ring against nouns: Tree sleeping, Flower staring, Morning hooting, Sweet day whispering. It’s not long before metaphors surprise us with their appeal to imagination: Light like a snake charmer piped up a wood anemone from the dark cold ground in a forest clearing.

On such a workshop even people who think they ‘can’t write’ surprise themselves. By drawing on concrete experiences and with help from the rhythm and motion of walking through a landscape, we can all enter such play. And so we walk a line of poetry to pulse it into life; create a character and take a journey in their shoes; draw maps and name our own discovered places.


A course at Moniack Mhor is permission to refresh eyes that may have been half-closed by habit and find out what words can conjure in company with others. This August myself and poet Valerie Gillies, who says, ‘open air and birdsong are the inspiration to my writing’, will be leading a five-day residential course exploring places local to Moniack Mhor in words and imagination across any written form. Well-known naturalist and founder of the nearby Aigas field centre John Lister-Kaye joins us as guest reader — a chance for a very intimate reading from this year’s book, ‘Gods of the Morning’.

moniack weekends 013

And if you fancy arriving on foot, here’s my account of one way of doing this!

For more information about Linda visit her websiteWriting & Place , with Linda Cracknell & Valerie Gillies, and guest Sir John Lister-Kaye, takes place Monday 24th-Saturday 29th August.  All images courtesy of Linda Cracknell.

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Newt homes for great crested Highlanders

In 2007 a Black Isle dog walker noticed a strange looking newt. A few months later, also on the Black Isle in the Highlands, a schoolboy discovered a great crested newt breeding site.

Great crested newt © Sue Scott/SNH

Great crested newt © Sue Scott/SNH

Before this, there were only a dozen known sites in the Highlands where these rare newts could be found. Because these were all close to schools, roads or houses, most newt fans and herpetologists thought their presence this far north resulted from human introductions. These new finds, however, were well off the beaten track and they led to a search for further sites. Today there are more than 40 ponds in the Highlands where great crested newts are known to breed.

Great crested newt - Ben Ross/SNH

Great crested newt – Ben Ross/SNH

Some of these populations have become isolated though, and there is concern this could lead to inbreeding and potentially to populations dying out. More recently research has shown that great crested newts in the Highlands are not only native, they are unique and quite possibly the most famous newts in the world! Local newt expert David O’ Brien explains below how an SNH pond building project is bringing people together to help these famous newts.

The project aims to build around 25 new Highland ponds in areas where great crested newts are thought to have bred in the past. The ponds are designed specifically to meet the newts needs and it’s hoped they will reconnect isolated populations, helping them to become more resilient and their numbers increase.

An almost finished great crested newt pond on Forres Golf Course.

An almost finished great crested newt pond on Forres Golf Course.

So, what’s so great about crested newts? Why are local people turning out and giving up their time to help them? In half a minute on great crested newts, David explains why these curious creatures have always fascinated him.

For more information on this “poster boy of the amphibian world” visit our website.

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The capercaillie

The capercaillie is the world’s largest grouse which, in Scotland, lives in open mature pinewoods. One of our most elusive birds it probably became extinct in Britain in the mid-18th century, largely due to the destruction of native woodland habitat.  In 1837, birds from Sweden were reintroduced into Perthshire and by the early 1970s there were thought to be around 20,000 capercaillie in Scotland. However, since then the numbers have fallen dramatically.

Male capercaillie

Male capercaillie


Thus the capercaillie is of high conservation concern in Scotland as the population has declined to less than 2,000 birds. Strathspey remains the stronghold with around 75% of the Scottish population and was therefore the centre of a recent study looking at their breeding success.

The study produced a report which is the result of a partnership comprising SNH, RSPB Scotland and the Cairngorms National Park Authority (CNPA) and produced some interesting findings.

Native Scots pine woodland

Native Scots pine woodland

One thing to emerge is that there are complex links to the success of capercaillie in rearing young and the following factors:

  • habitat structure
  • predator activity
  • weather during the egg-laying and brood rearing period.

Some elements of the new report have been found before. In particular the link between poor capercaillie breeding success and wet weather in June (when females have dependent downy chicks).

Female capercaillie

Female capercaillie

The report also found a weak association between breeding success and a measure of pine marten activity.

One interesting new finding was that blaeberry leaves (a key food item for capercaillie) had a better defence against herbivores through their chemical composition in old-growth Scots Pine forest than in younger plantations.

Blaeberry flower. ©Lorne Gill/SNH

Blaeberry flower.
©Lorne Gill/SNH

Adult capercaillie and chicks depend heavily on blaeberry leaves, and their associated insects, as food. However, further work will be needed to test whether forest management could help to increase the quality of blaeberry in forests for capercaillie.

Capercaillie detail

Capercaillie detail

Sue Haysom of SNH welcomed the new report and noted that “This report improves our understanding of the complex relationships between weather, habitat, predators and capercaillie breeding success and how these factors vary across key woods in Strathspey.”

Justin Prigmore of the Cairngorms National Park Authority also commented on the report noting that: “Strathspey is the most important area in Scotland for the species and is the only area where numbers have remained relatively stable. It is essential that we do all we can to ensure their long-term survival here. This work shows that it is a complicated picture but helps direct where we need to focus effort for the future and will further inform the Cairngorms Capercaillie Framework which is working across this landscape scale.”

The capercaillie is not an easy bird to see and is very sensitive to disturbance so if you want a chance of seeing this special bird without risking disturbing them check out Caper Watch which continues till mid-May at the RSPB’s Osprey Centre at Loch Garten.


Find out more about capercaillie on the SNH website @


Image credits – Image one by Mark Hamblin/2020VISION, female capercaillie ©Danny Green,  other capercaillie shots by Pete Cairns/2020VISION. All other images © Lorne Gill / SNH.


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