Four-mile walk taking in the River Stort and Bat Willow Hurst Country Park in Bishop’s Stortford ideal for school summer holidays

Nature Notes columnist Jono Forgham covers your fortnightly look at nature around Bishop’s Stortford

To conclude my trilogy of local habitats worth a visit during the school holidays, I decided to visit the River Stort from the town centre and take a wander north as far as Bat Willow Hurst Country Park.

I parked in the multi-storey car park, headed over to Sworder’s Field and joined the footpath that runs along the bank of the river. Several mallards headed my way anticipating food, but they were unsuccessful with their requests.

Plenty of work going on here and I was a little dismayed to see the hedge that surrounded the castle mound has been removed and replaced by iron railings. Gone is a nesting site for thrushes, blackbirds and robins. However, there appeared to be improvements to the banksides that look like they will encourage more vegetation here. Already plenty of purple loosestrife along this section.

I arrived at the tarmac stretch of the path heading towards Grange Paddocks; here, a solitary hogweed in full flower. Always attractive to pollen and nectar feeders, so I stopped to check the flowerhead. A large hoverfly species was present, Epistalis pertinax.

Here the vegetation was more mixed with Indian balsam and orange balsam. Both are non-native species and highly invasive. Growing in the river, plenty of sedges and reeds that could benefit from being cut back. A shoal of roach fed under the footbridge near the car park along with a few small chub. A pair of Moorhens were feeding their two juveniles. A second brood I would imagine at this late stage of the breeding season. Overhead, plenty of goldfinches and several linnets whilst a chiffchaff called from a willow.

A few banded demoiselle damselflies wafted along the far bank, too distant for a photo, their metallic blue bodies glimmering in the partial sunshine. These were males as the females are metallic green. Butterflies were ever present, mainly small and large whites, but I was waiting to photo these once I arrived at Bat Willow.

I watched from the bridge near the leisure centre thinking that it will only be a few months before the overwintering siskins will be returning to feed upon the numerous alders that grow along the river. I had hoped for a grey wagtail by the weir, but too many dogs were enjoying the water so I moved on. A thirsty wood pigeon popped down onto a handily-placed branch to stretch into the water for a drink as I crossed over the entrance road to the centre and gained access to the football fields.

A male kestrel darted from an ash tree whilst, overhead, I heard the alarm calls of house martins. I scanned the sky to discover they were mobbing a male sparrowhawk which was circling high over the fields.

I took time out to sit on a bench near a large meander hoping that the resident kingfisher would put in an appearance, but it was neither heard nor seen during the entire wander.

I crossed Cannons Mill Lane where a party of long-tailed tits zipped through the leaves. In total around 15 were present showing that, for some birds, it is already autumn. In the car park, a pair of large white butterflies were engaged in a courtship flight before the female settled upon the ground with the male flying overhead, occasionally dropping down to actually stand on her.

I entered what used to be known as the Red, White and Blue Field, named after the pub that used to be on the corner of Rye Street and Michaels Road. Now it seems to be called Grange Paddocks Meadow and has, at present, a herd of splendid English longhorns. Like the water buffalo at Thorley Wash they were very distant, so I decided to carry on and planned to get some photos of them upon my return. A common buzzard hunted overhead, its effortless flight aided by the warm thermals rising from the grasslands.

I crossed Michaels Road into Bat Willow where I headed immediately to the smaller of the balancing pools as this is a hotspot for dragonflies and damselflies. I wasn’t disappointed as plenty were on the wing. However, I did note that their numbers were considerably lower than they have been in the last few summers and wondered if the fish in the pool were feeding upon the nymphs. There were several goldfish and a couple of quite large carp. I presume the former have been added by locals, but the carp seemed too large to have been there since the pool was created. Maybe these too have been introduced?

I began searching the vegetation for roosting insects whilst also noting new plant species for the walk. The pervading scent of water mint was ever present. Common blue damselflies flew across the water as pond skaters whizzed across the surface, their legs making small dimples in the meniscus of the water. One roosted upon a reed leaf for a photograph whilst another kindly landed on the ground right in front of me.

Several species of dragonfly have a favoured look-out twig or leaf, so I stood near one that a common darter was frequently using and managed a few shots. A similar species arrived also; the ruddy darter. The easiest way to identify these two species is to check the legs. The common darter has yellow stripes on the legs whilst those on the ruddy are all black.

An emperor dragonfly was chased off by a large brown hawker. I got out my binoculars to check the surface vegetation and discovered many small red-eyed damselflies resting upon the leaves. This is a relatively new species for the UK list, first arriving in Essex in July 1999, and has now expanded its range to include most of Hertfordshire and surrounding counties. A good damsel to find at a new site such as this.

I enjoyed my picnic by the pool before leaving my camera bag etc and heading off to check the grasslands around the pool. Plenty of butterflies, but catching up with them with my macro lens was somewhat of a trial. Common blues were numerous, the female being, confusingly, brown and very similar to another species that was also present, the brown argus. I managed to catch up with a few of these before I began following a very flighty small heath. Again, after many attempts, I managed to get close enough for a reasonable photo before it flew off. These small butterflies have a habit of resting on their sides, showing off their distinctive underwing plumage.

I came across a stand of wild marjoram which is mainly a chalk-loving plant, but, over the last few years, I have noted an increase in this plant around the town, particularly along the River Ash south of Little Hadham and along the footpath north of Hadham Hall. This is another plant that is a favourite with insects.

Some years ago I netted a small micro moth from wild marjoram, a species I was not familiar with and, after a little research, identified it as Acompsia schmidtiellus, a species that had been declared extinct in Hertfordshire in 2006. A pleasing find indeed. Several more specimens of this small moth have since been added to the county records. The only previous record was from 1950.

After a good wander around I headed back to photograph the cattle which were still over by Rye Street. Such passive and docile creatures, they continued to feed as I took a set of photos.

On my way back I clocked mallow and bittersweet, both in full flower. Bittersweet is related to the potato and has very similar flowers, showing bright purple and yellow. Later in the year it will show bright red berries.

Not much was added to the day list as I took a wander along the side of the railway track back to Sworder’s Field. A lone herring gull headed towards the town as I checked the flowerbed by the swings where several bee species were busy nectaring.

I had covered about four miles there and back and noted many places for a picnic break as benches are placed regularly along the river and within Bat Willow, so well worth a saunter along to see what you can discover.

I arrived back at the car park and headed to Wetherspoons for a post-wander pint where, by coincidence, there was a beer called Dancing Dragonfly, which seemed to be an appropriate conclusion to a successful walk. An enjoyable beer.