Dragonfly heaven at a special Surrey heathland

Thursley Common, Surrey, June 2018

I’ve recently moved somewhere new and with that comes an interaction with new landscapes. In the United Kingdom, a distance of 25 miles can open up entirely new experiences in the outdoors through the sudden change in soils, topography and local culture. I have moved further south into Sussex, in touching distance of a tangled web of counties (West Sussex, East Sussex, Surrey and Hampshire), communities and habitats. One landscape that feels closer than it ever did is lowland heathland, a landscape I’ve come to learn more about in recent months.

I now know that dry lowland heath has been drastically lost over the past 150 years and it is rarer than rainforest. It is a human-made habitat with intrinsic ties to a pre-industrial way of life where local people grazed their animals, cut and burned heather, extracted sand, cut trees, but were unable to grow crops due to the poor fertility of the soils. It is subject to epic conservation projects in some places, like the Heathlands Reunited project working across the South Downs, tipping into Hampshire and Surrey in places outside the South Downs National Park.

My family have roots in Ireland and I have spent time there learning about the way of life of people who lived in the wild and very wet western areas. To my ancestors heather was an incredibly diverse resource. It could be cut at the right age to produce all manner of items, most fascinating to my mind were lobster pots weaved from woody heather growth. The subsequent cutting of heather allowed new growth and light to reach the heathland, benefiting many different species – denser growth for ground nesting birds, increased flower abundance – and a mosaic of vegetation lengths which further the species diversity through the creation of micro-habitats.

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With the popularity of the rewilding movement in the UK, heathlands are a point of contention because an argument for landscapes to be left to ‘adopt their natural state’. This is at odds with the desire to see heathlands humanised again, what is shown to produce the richest conditions for their wildlife. Heathlands which are ‘left’ or ‘rewilded’ become simply poor quality woodland in the sense of the lack of species diversity.

One site stuck in that tangled-web of counties is Thursley Common, a National Nature Reserve managed by Natural England in Surrey. I visited Thursley for the second time in June on a hot but mercifully breezy day. There were many thousands of dragonflies on the wing – so many I declined to ‘tick off’ the vagrant red-backed shrike which people were heading over to see but completely ignoring the riot of Odonata  – and the sandy paths were brimming with rare insect life.

Having visited Thursley a year before with a tour from the site manager, I had an idea of where the good stuff was and some background on their ecology. Over the winter I had looked forward to returning to try and photograph the heath sand wasp and mottled bee-fly. Thankfully the weather was perfect for this.

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Kneeling down on a sandy track it was possible to see the heath sand wasp, found only on lowland heath, mainly in the south of England. It was caching moth larvae that it had been hunting out in the heather. It’s hilarious how they use a small roll of sandy soil to close their doorway before heading off again to hunt on the heath.

They have every right to be cautious. Lying in wait on tiny scatterings of twigs were mottled bee-flies, a rare insect that parasitises the nest of the sand wasp. It wasn’t clear whether the sand wasp was wary of me or suspicious of the presence of the fly (do insects experience suspicion?) but at times the bee-fly deigned not to move, creating a kind of stand off between the two insects as the sand wasp waited to fly off to hunt and the bee-fly waited to hover and throw its eggs into the hole.

Sure enough, after the wasp had moved away, the bee-fly was hovering over the nest hole, chucking its eggs in like a footballer volleying the ball into an open goal.

These are two species which, without managed heathlands (interestingly much of the management they benefit from is the result of footfall exposing sand along the paths) would be lost. Woodland’s return would mean a loss of light, warmth and resultant heather growth where the sand wasp’s prey is found, meaning that the structure that binds these species would collapse.

Another unusual insect along the paths was the hornet robberfly. This is another type of fly that can be found in heathland and is classified as rare. It is possibly the largest fly in the UK but it looks like a hornet. Like many of our flies (bet you don’t consider them your own) it mimics the appearance of a predatory wasp to give a greater sense of protection. In terms of natural selection, it has survived probably because it looks like a species that has a world-shattering sting at the tip of its abdomen.

Robberflies do exactly what their name suggests, they steal insects and eat them, sucking them dry in about thirty minutes in the case of the hornet robberyfly. The best way to see them is through a macro lens and to hang out somewhere that you know has lots of other insects present. Some stunning photos are out there with robberflies holding on to their fly prey.

I spotted the hornet robberfly because it was sitting on a pile of manure, exactly where it likes to spend its time in life. It was using the manure as a perch to hunt where it can blend in with the hay stems that a horse or cow can’t quite digest. They also lay their eggs in the crevices of the dung.

It was a privilege to see these rare species, unseen to almost everyone (obviously), only present because of good management and an appreciation that human impacts can be positive for living things other than ourselves.