Thorley Wash Nature Reserve

Nature Notes columnist Jono Forgham’s second in a trilogy of guides to local habitats that are perfect for a school holiday wander. This week: Thorley Wash Nature Reserve

There are three ways to access this splendid reserve, which is managed by Herts and Middlesex Wildlife Trust. Firstly, park in the car park in Pig Lane just before Twyford Lock and pick up the footpath heading south. After a mile along the Stort Navigation, there is a brick bridge that leads onto the reserve.

Secondly, park near Spellbrook Lock in Spellbrook Lane East and head north to the bridge. Finally, park in the lane leading to Challenge Gym off the Spellbrook road, head back 400 yards and take the footpath through a bramble and willowherb field, over the railway line and into the reserve.

The weather forecasts of late have been rather inaccurate and a glance at last week’s made Monday (July 31) the best day to visit. Consequently, I set off fairly early, parked in Pig Lane car park and got onto the towpath. Leaden skies, breezy conditions and the threat of drizzle didn’t fill me with much optimism of finding much – and so it proved.

Several banded demoiselle damselflies darted over a nettle patch, their metallic blue colours somewhat dimmed in the poor light that made photography challenging.

Mallards and moorhens patrolled the river whilst, overhead, swallows and house martins hawked for insects above a copse of alder trees. These birds’ numbers will soon increase along the river as they follow it for their migration south.

A large helix species of snail sauntered across the path, moving as rapidly as a snail can manage as it was out in the open and therefore liable to be predated. This one made it to the safety of the grass verge and back into cover.

All along the riverbank were good stands of many wildflower species: willowherbs, purple loosestrife, teasels, forget-me-not, common comphrey and large bindweed with its white, bell-shaped flowers. It’s worth checking these for pollen-feeding insects and, in one, an Episyrphus balteatus hoverfly, aka the marmalade fly. It was so grey I needed to set up the flash for a photo.

Goldfinches and linnets circled in small groups, calling constantly. Both great spotted and green woodpeckers called from afar as I approached the bridge.

It dawned on me that I had recorded no butterfly species at all, but this was soon rectified when one of several small whites sailed by and landed on bindweed for a quick photo. This was the only species I saw in the three hours I was in the field.

I went through a small, overgrown copse before emerging with sedge and reeds either side of the track. Here, huge stands of purple loosestrife, meadowsweet and hemp agrimony were in full flower – a pleasure to see.

I headed to a favourite spot where many insects have been recorded over the years. By the footbridge leading out of the reserve over the railway line is a stretch of nettles and comphrey. I changed lens to my close-up macro, put my gear down and had a wander along the path to see what I could find. Very little, as it happened, due to the grey and gusty conditions.

On a comphrey leaf was a click beetle species showing a dark head with brown wing case. One of several species were possible, but I suspect it was the common Athous bicolor. An amber snail sat upon another leaf before a flickering movement in the grass attracted my attention. A field grasshopper posed long enough for a photo before leaping away. I always wonder if grasshopper and cricket species actually calculate where they are springing too or just hurl themselves into the vegetation.

I checked the heads of knapweed and here several common red soldier beetles (Rhagonycha fulva) were feeding upon the pollen. On one flowerhead, a pollen beetle species was also in attendance.

I then scanned the sedge fields to the south and, right in the distance, was one of the reasons I decided upon this habitat: a herd (or obstinacy) of water buffalo. These had recently featured in a wildlife photo for The Guardian, so, if good enough for that publication, surely good enough for the Indie. I thought I would carry on checking for more insects and then take a wander to see these beasts.

Upon another comphrey leaf was a small yellow fly: Chrysopilis asiliformis or little snipefly, a regular resident of wetland habitats. Another insect landed nearby before hopping off straight away. I caught up with it, a common froghopper (Philaenus spumarius).

The sky darkened, the breeze picked up and drizzle began to descend. I covered up my optics and thought I would head home to return later for water buffalo shots. On my way back I managed distant photos of both the banded demoiselle and a blue-tailed damselfly.

The forecast for the rest of the day and Tuesday looked dismal, so I processed my photos and caught up with nature records from a few surveys I am involved in.

Tuesday dawned bright and calm, so back to Thorley Wash, this time parking by Challenge Gym and walking over the railway line straight to where I had been based 24 hours earlier. A whitethroat popped up from the brambles as I stopped to photograph the common toadflax that grows in profusion right next to the railway line – the only place locally where so much of this attractive plant can be found.

I set off to find the buffalo but, handily for me, they were heading towards me, offering photo opportunities. This herd of 10 will be on site until autumn, helping to keep the grasses etc in good health. They were certainly chomping through this while I was present.

A red admiral butterfly alighted for a photo as several gatekeeper butterflies worked their way along the path, stopping briefly to nectar upon the loosestrife and common fleabane. With the change in the weather, there was much more insect activity.

I noted red galls growing on the underside of the willows that border the Stort backwater. These are made by a small wasp species, the leaf reacting with the chemicals that the wasp deposits. The leaf produces a red swelling in which the wasp larvae grow. There is no damage to the health of the tree as it would not be in the interest of the wasp to damage or kill the tree as it is the only host it uses for raising its grubs. The gall is called willow red bean-gall and can be very prevalent in early autumn.

A flock of 16 herring gulls meandered northwards as a kestrel flew from a large oak. I got back to check the lower vegetation and came across a bright metallic green fly, one of the Lucilia species, commonly referred to as greenbottles.

By now the buffalo had wandered off to the middle of the habitat and taken up residence under a small stand of willows. A common buzzard called unseen and another great spotted Woodpecker bounced overhead with its characteristic jerky flight.

From the railway footbridge, there is a path all around the reserve with a few hand-carved benches for picnics. One depicts otters whilst another shows water voles, so a perfect spot to take a break and watch the nature go by. Even on poor weather days there are things to find and, on a sunny, warm and calm day, there is plenty to see.

It is well worth the short amble to see what you can find, with the added bonus of water buffalo – not an everyday sight around Bishop’s Stortford.

My next offering will be the final in this trilogy of good places for a family visit – one that is easily accessible from Stortford and offers a wealth of nature possibilities.

Finally, a correction. My previous piece, about Aubrey Buxton Nature Reserve near Stansted, had photos of a brimstone butterfly and a comma butterfly. Somehow, the captions were transposed. The bright yellow butterfly is indeed the brimstone. Thanks to those who pointed this out.

Enjoy a nature walk and picnic at Aubrey Buxton Nature Reserve near Stansted in the school summer holidays