Special places, hidden stories

Sphagnum moss by Ross Hadinott

The BBOWT team tell us about their favourite spots and what makes them so special. This month: moth trapping on Wildmoor Heath

In this blog series members of our team share a photo of their favourite spot on our reserves, and tell us the story behind it: what makes it so special, and the work that goes in to maintaining it. There’s always more than first meets the eye!

This month Roger Stace lets us in to the secret world of all-night moth trapping on Wildmoor Heath, and some of the amazing species recorded there.

Wildmoor Heath by Roger Stace

Wildmoor Heath by Roger Stace

JM: Could you start by introducing us to Wildmoor Heath?

RS: Wildmoor Heath is a 90-hectare site near Bracknell in Berkshire, it’s a SSSI [Site of Special Scientific Interest] and an SPA, a Special Protection Area, which is a European designation for the heathland birds that are found there – nightjars, woodlark and the Dartford warblers that do well there. The SPA covers a whole swathe of heathland in the Thames Basin, so across the whole SPA those are the key species - on Wildmoor we don’t have quite enough open ground for the woodlark, but nightjar and Dartford warbler do well and they breed there every year.

These birds, especially the Dartford warbler, are heathland specialists, so you won’t see them on any other habitat, and we’ve lost something like 80% of our heathland across the UK since the 1700s. In Berkshire a study comparing maps from the 1700s with ones from about 10 years ago found that there was a 98% reduction in heathland cover in Berkshire, so what we’ve got left is really important. It’s not just Wildmoor in that area, we’ve also got Broadmoor Bottom; then there are our heathlands in West Berkshire as well.

Heathland hasn’t had quite the same media coverage as wildflower meadows, but they’re an equally important habitat with some very specialist species, not just the birds but reptiles as well. Our remaining adder population in Berkshire is mostly found on heathland, and if you go further south you get species like the smooth snake and the sand lizard as well, which are very much heathland specialists.

JM: Why did you choose this particular site?

RS: Wildmoor is probably the most unique of the heathland sites we have in Berkshire in terms of the mixture of wet and dry heath. It’s a fantastic undulating site with valley mire areas at the bottom full of sphagnum mosses, bog asphodel and even little carnivorous plants – the round-leaved sundews that have little sticky leaves to catch insects on. We see them regularly – they’re rather unassuming, just a few millimetres across the leaves, they’re not great huge things that’ll take your leg off!

Lots of people live round there so some places on the reserve are quite busy, but on the right day you can lose yourself amongst the heath and feel properly in the wild. And because it’s part of the wider Thames Basin heaths, if you find the right vantage point you’re not just looking at Wildmoor, but across bigger swathes of extensive heathland out across the Thames Basin.

Wildmoor moth trap by Roger Stace

Wildmoor moth trap by Roger Stace

JM: Tell me about this first photo.

RS: This is the place where we did our moth trapping last year. There’s a lovely area of dry heath with a mixture of different heather plants growing across this area, and a scattering of pine trees including a particularly large one with a little bench under it which is where we set up for the night, looking out across the hill into the valley mire. In this picture you can see two species of heather – bell heather and calluna or ling heather, then there’s the Scots pine, birch, bracken and in the far distance is the mire where the mist is rising, the wetter area with all the sphagnum mosses and sundews and so on.

That was just a really lovely spot, particularly as it was getting dark, the visitors had all gone so you’d got the place to yourself. The nightjars started chirring away, we set up our moth traps and they started arriving.

One of the things I especially like about doing moth trapping on our nature reserves is that you get to see them in a whole different light – that doesn’t quite make sense does it?! But it paints a different picture of the reserves when you’re there in the dark and you see everything in a different way. So I feel fortunate that I’ve taken up moth trapping as a hobby that I can tie into work and visit some fantastic places when different wildlife is active. The owls off in the woodlands hooting away, nightjars on the heath, the moths and bats flying around you, glow worms at the right time of year as well.

JM: What happens on a moth trapping expedition?

RS: We arrive an hour or so before sunset to scope out the area, and decide where we’re going to put the traps. You put a white sheet down underneath each trap to enhance the light – the moths will go into the trap but a lot of them will also fly around and land nearby so it just allows you to see them that much more. There’s lots of reeling out of cables and setting up a generator somewhere not too disturbing (and we usually chain it to a tree as well just in case!).

I usually invite along members of our team at BBOWT, but I have a regular group of moth trappers, or moth-ers as we say, and they’re the real experts who’ve been doing it for decades. I’m still very much in the learning phase having been doing it for seven years. There are 2500 species of moth in the UK, which are divided into micro-and macro-moths (although some micromoths are bigger than some macro-moths, just to confuse everyone!). That’s why it's good to have the experts there – it’s a lot to remember!

Moth trapping by Adrian Wallington

Moth trapping by Adrian Wallington

Once we’re all set up it’s just getting dark so we fire up the generator and the lights. There are lots of different variations of moth trap, from build-your-own to £300-400 models, but it’s basically a bright light with some kind of box with a funnel. The moths fly towards the light, go into the funnel and drop into the box. You tend to put egg boxes inside because they’re nice and easy for the moths’ feet to hold onto, and they can hide themselves away in the nooks and crannies and feel safe.

We often have eight or ten traps of different kinds scattered around the reserve and we tend to circulate between them through the night to see which moths are coming in. It keeps us fairly busy! We make our way around the different traps, open them up and a few moths will inevitably fly away. But you can then go through the egg boxes and record everything you find. We take them out to identify them and then they fly away again – there’s no harm done.

JM: Do you stay all night?

RS: This particular night on Wildmoor three of us stayed all night – or rather, I slept in the back of the Ranger for three or four hours. The best time for moth trapping is high summer, when it’s not getting dark until 10pm anyway, and getting light at 4am. So we’ll be going around checking and recording until one or two in the morning, getting a bit of sleep and then trying to get back up for the dawn. You’re not good for much the day after that! I tend to eat a lot of chocolate to keep me going – I don’t drink tea or coffee so I can’t rely on caffeine!

Clifden nonpareil by Roger Stace

JM: What’s your most exciting record so far?

RS: Probably my first sighting of a Clifden nonpareil at Snelsmore four or five years ago, I’ve got a very clear image of the first time we saw it – it hadn’t come to the moth trap but someone was walking between traps and saw one flying around, and this is a big moth, about the same size as Britain’s largest butterfly, the Swallowtail. As well as the iridescent blue on the upper side of the hindwing, the undersides of both the fore- and hindwings are bright white with black stripes, so seeing it in torchlight flying around was really vivid and exciting.

True lover's knot by Roger Stace

These are some of the other species we saw that night. First, a true lover’s knot - it’s quite small, but I like the moths that aren’t necessarily big and showy - the really intricately marked smaller ones are beautiful. This is a heathland specialist that feeds on heather and bilberry, so we always catch them when we’re anywhere near heathland.

Pine hawk-moth by Roger Stace

This is a pine hawkmoth – there are a number of pine trees near where we were trapping. I do like the big chunky hawkmoths as well! Great meal for a nightjar or bat too.

Black arches by Roger Stace

This moth is called a black arches. I love the huge feathery antennae, which are a way of telling that it’s a male moth. The females release pheromones and a lot of species have these big antennae in the males, which they use to detect the pheromones.

Buff-tip by Roger Stace

This is a buff tip – I just love these moths, the camouflage is incredible. Spot the moth! The evolution and development that a moth goes through to eventually end up looking like a broken twig just blows my mind.

Elephant hawkmoth by Richard Burkmar

And finally an elephant hawkmoth, I always love to find these.

JM: Where does the data go?

RS: The data all goes into our big database of species records for BBOWT nature reserves. It’s useful to have an idea of what key species are there, and we might occasionally tailor management to support them but that’s actually quite rare. The data is more useful in that it goes to the National Moth Recording Scheme – there’s a county recorder for each county who compiles a picture of how moths are doing year on year within Berkshire, for example, and that all goes into the national database. It’s really useful data for building up a picture of how species of doing on a national level, and how climate change, habitat destruction, intensive agriculture and light pollution might be changing populations.

JM: Have you noticed changes in populations over the last seven years?

RS: You definitely notice changes year to year in terms of how moth numbers are doing – you get better years and worse years. Speaking to anyone who’s been doing it for a length of time, you’ll see that there are trends, particularly in abundance – there are species that have gone from being common to being rare or even locally extinct. But then there are also species whose numbers have increased – a nice example of that is the Clifden nonpareil I mentioned earlier. Even five or six years ago everyone got excited when we got two or three records in the whole county (normally it’d be a migratory moth so you’d get a few records later in the year). And then people started recording it quite frequently on Snelsmore Common, and now we’re getting hundreds of records per year where it seems to have settled and started breeding locally. Its caterpillars eat aspen, so it’s got plenty of food plants around. Sadly the overall trend for moths along with many other insects is not a positive one.

Roger Stace has worked for BBOWT across all three counties, and is currently Land Manager for West Berkshire.