Plenty of wildlife to spot on a walk around Thremhall Park and the Stansted Airport lagoons
The Indie's Nature Notes columnist Jono Forgham covers your fortnightly look at nature around Bishop's Stortford...
For my latest Nature Notes wander I had planned to cover the Flitch Way from the start of the walk near the petrol station on the Takeley road, walk as far as Thremhall Park and spend time checking out the mixed habitat, before wandering back when the temperature was supposed to be at its highest as this would encourage the insects to be out and visible.
However, the road to Gaston Green was closed so a quick change of plan. I parked at Thremhall Park, registered my car on the tablet in the splendid café, where I enjoyed a coffee, and then picked up a footpath on to the Flitch Way opposite Kearsley Airways.
The sky was grey and threatening as I wandered along the old railway line and little was noted for quite a while. At a stand of hogweed, I stopped to check the flowerheads and here were a few Eristalis pertinax hoverflies nectaring. They were joined by a smaller hoverfly, certainly a melanstoma species and one that required closer examination. I pulled out my hand lens to inspect the compound eyes and noted a small amount of "dusting" between these, suggesting this insect was probably Melanstoma mellinum.
A good start to the day as I checked a buddleia that was in flower, but the low temperature and breezy conditions were not conducive for insects to be on the wing. A blackbird darted across the path whilst blue and great tits called from Hatfield Forest on my right.
I arrived at Stane Street Halt and enjoyed a snack on the bench here. A chaffinch sang from an adjacent garden and, way off in the distance, a juvenile common buzzard mewed. I decided to pop over to the Stansted Airport lagoons to see if there were any migratory birds passing through and feeding ready for the journey south. I was not to be disappointed.
I took the path down to the lane, under the bridge and turned right along the old Takeley road to the last building, Primo, a bathroom and tile business. Here, a footpath takes the wanderer into a field and then, soon after, over a footbridge. This path forks and I took the left-hand one, pushing through overgrown vegetation that encroached over the path. I emerged at the lagoons and could immediately see I was going to get loads of bird species.
Canada geese were at least 60 strong with several greylags consorting with the armada of Canadas. I fired off some photos, but by now the light was really poor as I adjusted the settings on the camera to permit more light through. Still these were grey and grainy, but the best I could do.
I sat in the long grass by the largest lagoon and scanned the whole area. Gadwall and mallards were the main wildfowl with several tufted duck. A family of mute swans sailed serenely on the other side until the geese encroached and then both adult swans raised their wing feathers to increase their size, put their head down into their chest and swam rapidly towards the geese. The swans swam so fast they created a bow wave and soon the geese had retreated. The male swan (cob) stayed in situ whilst the female (pen) returned to the five cygnets whereupon they carried on feeding. The cob struck an aggressive pose and no goose dared venture close. He certainly was the king of the lagoon.
In the far corner was plenty of exposed mud. Little egrets waded in the shallows and a common sandpiper probed the mud and picked off insects from the surface. More photos with which I was not happy.
Flying rapidly over the surface were plenty of sand martins along with a few house martins, recognisable by their white rump, as well as the occasional swallow. The light was far too grey for flight shots, but I tried nevertheless. A grey heron flew overhead and a kestrel hovered over the grass verge.
The grassy areas around the lagoons were in full flower. Wild carrot, knapweed, ragwort and thistles dominated along with several vetch species. I encountered a briar rose pushing through the taller plants and noted a strange, ragged red flower growing upon it. This is known as Robin's pin cushion and is created by a gall wasp species (Diplolepsis rosae). Basically, the wasp lays an egg near a bud and the rose reacts to the chemicals and forms a gall around the egg, into which the wasp larva crawls and lives and feeds. The chemicals also make the rose bud produce the ragged petals that further protect the wasp larva from predation. Remarkably, there is a smaller wasp species that lays its eggs on the wasp larva so that grub feeds upon the larger larva. A parasite parasitising a parasite!
I carried on around the lagoons. A few butterflies, mainly gatekeepers and meadow browns, were on the wing, nectaring upon ragwort. I tried a few macro shots before heading back to the Flitch Way. I stopped once again upon the bench for my picnic. An autumnal party of long-tailed tits flicked by as, halfway through my sausage roll, it began to rain. Just that type of drizzle that is very good at getting you very wet quickly. No waterproofs, so I just shuffled along the bench a tad and took shelter under a large oak. My crisps became sodden, but everything was fine. Good to be out after a few days on the laptop. My trusty hat of many years did its job and kept my head dry.
With my damp picnic completed, I returned to Thremhall Park and headed off to check the ponds for dragonflies. A brown hawker darted over the surface and an emperor dragonfly patrolled his territory but little else, save for a flash of a reed bunting diving for cover.
I decided to cut my losses and returned home to download more than 250 photos – all bar eight were of little value for this article. I checked the forecast for the Tuesday and mid-afternoon looked best, so the following day I returned to the lagoons in far better light and much drier conditions.
What a change! Gone were all the geese and sand martins, but now three little egrets were wading in the shallows. The light now offered pleasing shots, complete with reflections. Little grebes dived for small fish and a family of coots ferried across the smallest lagoon, their juveniles no more than 48 hours old.
My attention now turned to the flowers: more gatekeepers and meadow brown butterflies but also a common blue that remained whilst I took a few macro shots. Nearby, common blue damselflies weaved their way through the tall stems of the wild carrot. A Bombus terrestris bumblebee (buff-tailed bumblebee) had fallen asleep which made for a decent photo.
A little further along, a latticed heath macro moth roosted near ragwort as more damselflies became evident. A chiffchaff called from the bushes and a party of gulls moved in over the water. Three juvenile lesser black-backed and three first-winter black-headed gulls. They appeared to pick food from the surface before heading off towards the airport.
As I was heading back to the footpath I heard a light and high "pri pri pri" call. This is the flight call of a little ringed plover. I caught a glimpse of a pair low over the water before they landed on the mud. I wandered back for a photo, but these were flighty birds and saw me and were off to the far end of the large lagoon. They will have been on migration from, possibly, a coastal site or local gravel pit and will have stopped for sustenance before the long flight to sub-Saharan Africa.
I now had a reasonable set of photos, so returned to the car parked near the Green Man pub. Back home, I was a lot happier with these photos and now had enough to include here.
Both Thremhall Park and the lagoons are worth checking out. The café at Thremhall is open until 2.30pm, serving a range of snacks, lunches and drinks. As I said earlier, just enter your car registration into the tablet on the wall in the café and feel free to wander around the woods and ponds.
From now until mid-October, the airport lagoons have the potential to attract many migrant species, particularly waders and small hedgerow birds. In previous years I have recorded bar-tailed and black-tailed godwits, avocets, greenshanks and dunlin as well as stonechats, whinchats and, on one occasion each, ring ouzel and stone curlew. Consequently, it is a habitat I shall be checking regularly, and definitely during and after any strong easterly breezes we may have this autumn. Anything may turn up in such favourable conditions.
After discovering all the species that I did find, I was grateful for the road closure to Gaston Green.