Lots of wildlife to spot on a four-hour walk around Bat Willow Hurst Country Park in Bishop’s Stortford
Nature Notes columnist Jono Forgham covers your fortnightly look at nature around Bishop’s Stortford…
Having done my two previous articles from the River Stort, I thought a different habitat would be refreshing and selected to have a good study of all the wildlife at Bat Willow Hurst Country Park. This is to be found on the road to Farnham just a few hundred yards along from the roundabout at the end of Rye Street with the car park on the right before the A120 bridge.
I arrived early on bank holiday Monday and had a good wander around, checking the bird species. Plenty were in good voice with chiffchaff, whitethroat, blackcap and two willow warblers noted as I headed to the first of the two balancing pools that hold water. Nothing here apart from three swallows that were dropping down to drink whilst remaining upon the wing.
I then moved to the smaller pool. This is a really good site for a selection of dragonflies and damselflies in high summer. I checked the sedge and reeds for any of these odonata species but only discovered the exuvia of damselflies. This is the case from which the insect emerges having spent up to three years in the pool as a nymph. When they are ready to emerge, they crawl up pondside vegetation and break open the case to appear as fully functioning damselflies. They then fly to nearby trees to rest and let their wings stiffen. I searched the stand of what I think are purple sycamores. Certainly a member of the acer family, but no damselflies were visible.
However, it was now warming up a little and insects were appearing so I decided to use my macro lens to try to get photos of the smaller species in the park. Always a tricky decision as it means my camera can only photograph things from a maximum of a metre away, so no bird photography at this time.
I took the perimeter path all the way around, checking the upper sides of leaves as well as the blossom on apple, guelder rose and hawthorn. Not a huge amount about, but enough to keep me busy. Fly species were apparent and I managed to get close-up shots of a Tachina fera fly. This is a smart yellow and black insect that posed well. Another fly species was nearby, a Lucilia sericata, one of the greenbottle species, this one showing a smart metallic green thorax and abdomen.
On the other side of the path was a good stand of nettles. I do like nettles when out insect hunting and rarely do I fail to find good stuff. Plenty of Pisaura mirabilis spiders, the nursery web spider. These arachnids sit on top of leaves with their first two sets of legs outstretched and together. This makes them look like a six-legged insect and so hoverflies and other insects land close by. The problem with trying to get a good photo of them is that they have great eyesight and drop off the leaf if they see you approaching. Also, trying to get near enough for a photo often means knocking the plant and, again, they scuttle for cover. Eventually, I managed a reasonable shot.
I headed off again and encountered swarms of crane flies, or daddy longlegs as they are often referred to. These were the species Tipula vernalis, showing amazing green compound eyes.
Overhead, starlings were shuttling between nests and local trees. On their return journey their beaks were crammed full with caterpillars and insects, obviously having far more success than myself at finding these.
A spindle tree was just into leaf and at the end of the branches were webs containing a mass of writhing caterpillars. These were the larvae of the micro moth Yponomeuta cagnagella or spindle ermine moth. They can remove almost all the leaves from the tree which does not appear to harm the tree as leaves reappear once the cats have pupated.
I continued my search, encountering many black aphids and two species of ladybird. Firstly, the common seven-spot ladybird and then invasive species the harlequin ladybird. The latter comes in a variety of patterns and the two I came across were very different, one being black with two red spots whilst the other was red with many black spots.
My attention was now drawn to ground level as I searched for more spiders. Plenty of plants here with ground ivy, germander speedwell and small flowering geraniums in abundance. Spiders scurried for cover in front of my footfall so I decided to sit and wait to see what came along. Right next to me was a black ant nest. A click beetle species, Athos bicolor, had stumbled into the soil pile and was swiftly attacked by the ants, bitten and killed before being dragged off into the underground nest.
Also by my side was the plant Alliaria petiolata, the garlic mustard. I checked this for eggs of the orange-tip butterfly, but none were apparent. A large stand of common comfrey was also here, its mauve flowers hanging like a set of church bells.
The sun appeared so I was now casting a shadow which makes insect photography even more tricky - if your shadow falls on the creature, they are off. Also, insects do not like carbon dioxide, so exhaling whilst close up moves them on also. If you ever come across me looking breathless with a camera it is because I have been holding my breath whilst trying for a photo of a fly or similar! I approached a roosting red admiral butterfly, but my shadow disturbed it whilst a small copper butterfly saw my approach and was gone. I did catch up with the red admiral a little later.
Much more was becoming obvious as the temperature increased. Fly species sunned themselves upon leaves and I caught up with several species, including an Exorista lavarum and the similar Sturmia bella, before a flitting micro moth caught my eye. It settled near me and I shot off a stream of photos. A small insect with a wingspan of 15mm and with antennae that are over twice the length of the body. It also has a name considerably longer than itself; Nematopogon swammerdamella, one of the longhorn micros.
By now I had enough photos of insects and plants, so reverted to my large lens and checked the whole habitat once again for birds. A grey wagtail was feeding by the smaller balancing pool whilst a pied wagtail posed nicely for a photo. A blue tit popped into view and a singing whitethroat showed briefly. These birds have a very obvious song, a scratchy warble of notes, usually delivered from deep in a bramble patch, but occasionally sung from the top of the bush.
On my final circuit I got chatting to a cyclist who recognised my hat from the photo at the top of these pages. We watched as the swallows continued to drink and more starlings darted overhead with even more insects. Where were they finding so many?
One final check gave me a great view of Bombus terrestris, the buff-tailed bumblebee. This one had obviously been nectaring and was rather damp, so it had hooked itself onto a leaf to dry out, making photos relatively easy.
After a wonderful four hours of nature watching I headed back to the car and returned home to check the moths in the garden trap. Glad I did as, perched inside, there was a splendid poplar hawk moth, one of the larger British moths with a wingspan of up to 8cm. An impressive creature.
I highly recommend a trip to this fairly new country park that seems to improve with each year and is now the go-to place for dragonflies in the town. Sadly my trip was just too early in the year, but I shall be returning frequently to catch sight of these really colourful and fascinating insects.
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