Spring wildlife spotted in autumn on circular nature walk from Wickham Hall in Bishop's Stortford to Farnham on Hertfordshire/Essex border
The Indie's Nature Notes columnist Jono Forgham covers your fortnightly look at nature around Bishop's Stortford...
A quick glance at last week's weather forecast informed me that the Monday would be the best day for a local walk and so it proved. By midday the temperature was hovering around an unseasonably warm 17C with good sunshine.
I parked at Wickham Hall and enjoyed a pre-wander coffee at Rosey Lea before setting off along tracks that would take me to Farnham Lane. I was most expectant about coming across something unusual and so it proved, eventually!
I began by checking the hedgerows along the track east of Wickham Hall where there is a considerable amount of wych elm, along with a few stands of English elm. These hedgerow plants do well for several years, but when they reach around 30ft tall they are struck by Dutch elm disease and die very quickly.
There are basically two theories as to why this happens when the tree reaches a certain height. One is that the beetle flies at 30ft and so encounters the tree by chance, whilst the second, and for me, more plausible, is that the tree at this age has reached a stage where the wood is to the liking of the beetle.
A quick search through local hedgerows will show plenty of elm species as well as dead trunks of trees that have succumbed to the disease. Several insects rely on elms as the food plant for their larvae, in particular the white-letter hairstreak butterfly which is solely reliant upon elm. Wherever there is a good quantity of this tree then it is probable that the butterfly will be found during its peak flight time of around the last fortnight of June.
Another insect that has other food plants to utilise is the micro moth Epinotia abbreviana. In high summer, swarms of these small moths can be knocked from elms. Today, just some leaf mines left by a variety of caterpillars munching their way around the soft leaf tissue between the upper and lower epidermis.
Another spectacular leaf mine I encountered was upon a large burdock leaf, a wavy pattern of white showing where the grub of the Phytomyza lappae fly had fed. On one leaf there were many tracks left by numerous grubs.
I headed on, passing the site for the new school, and eventually arrived at Farnham Lane by Oak House. Here, plenty of birds calling from the trees but none willing to pose for a photo. I heard goldfinches in number, several linnets, great tits, blue tits and a wren all searching for insects that should now have finished their season.
The warm weather of late October has confused nature, with many signs of things acting as if it is spring. This was certainly the case with flowering plants. Yarrow and hogweed were all in flower along most of the verges I checked, as were dandelions, dogwood, chamomile daisy and field scabious. Even bramble was having a flush of flowering. However, the biggest surprise was coming across a small stand of Alliaria petiolata (garlic mustard), which is an early-spring flower and vital for orange-tip butterflies as they lay their eggs upon the leaves.
All in all, somewhat concerning and it is clear we require colder temperatures and some good, hard frosts. None seem to be on the horizon as we continue to have warm southerlies at present.
I wandered up the lane towards Farnham. A blackthorn was groaning with sloe berries while, overhead, came the familiar "chack chack" call of fieldfares that will have recently arrived from Scandinavia to overwinter here. The first I have heard this autumn.
High and very far away a bird of prey circled, so out with the binoculars. As is so often the case, the bird immediately dipped behind some distant large oaks but soon reappeared. A large peregrine falcon that went into a stoop before rising on the thermals and heading off to the north. Superb bird to see locally. This is a species that is increasing its range and I expect to see them more often over the forthcoming years. I fired off some photos which confirmed the ID, but too distant for inclusion here.
A large bracket fungi pushed its way from a dead tree stump out into the verge as I wandered past the lane to Walnut Tree Cottages, but I continued uphill to the farm where I picked up the lane to Upwick Green. This is high country for the area, affording good views over the fields. Bullfinches called from deep vegetation – a shy bird, not prone to sitting out in the open. A female flew along the hedge, her white rump and back tail showing well in flight. This hedge also had flowering dogwood emerging and, upon one flower, an Anthomyia species of fly was nectaring.
House sparrows called from a garden and several popped up for a photo before I returned to checking the hedges and the verges. Long chains of red berries of bittersweet wound their way through field maple branches, adding a splash of red. Rosehips and hawthorn berries added more red hues, as did the fading dogwood leaves. Another flower came into view, meadowsweet, and, again, one that should have finished flowering in early September.
I continued under the power lines that march north/south in two parallel lines and soon came to the farm track that leads back to Bloodhound's Wood and Wickham Hall. A party of long-tailed tits flitted along the top of a hedge and a magnificent male yellowhammer caught the sun for a photo.
Overhead, the unmistakable "cronk cronk" call of a raven. Like the peregrine, this large corvid species is increasing in number around the town with several pairs having bred successfully in some of our woods, including Hatfield Forest. I recorded two juveniles with parents not far from Tesco in September. Hertfordshire ornithologists would have been very excited to see these two species here just eight years ago, the raven in particular having been extinct in the county between 1846 and when it bred again in 2006. Nowadays, I see or hear one frequently around Little Hadham. As with the peregrine, the bird was too far off for a worthwhile photo.
I approached the large barn adjacent to Bloodhound's Wood and upon one of the pylons was a throng of starlings. They appeared to be feeding in the lucerne crop before returning, somewhat raucously, to the pylon. A pied wagtail called from the roof of the barn as a female kestrel hovered over the field. In the distance, black-headed gulls and a red kite. Indeed, good bird country around Wickham Hall.
I sat upon an old and rusty piece of farm machinery for my picnic. A great spotted woodpecker called from the wood opposite, as did a pair of nuthatches. As I munched, I noted a stand of ivy, still in flower, which was attracting four hornets. More were seen patrolling the path, so I suspect a nest nearby.
Once finished, I packed up and headed along the wide track back to Rosey Lea for another coffee, but not before checking the flower heads of Achillea millefolium and hogweed. Several small insects here as well as a few late Apis mellifera, the western honeybee.
As I approached the barns and grain silos several pied wagtails called, with one posing wonderfully for a portrait with a fine blue, cloudless sky as a backdrop. Great way to finish such a pleasant wander with so much recorded, even though some of it I shouldn't have been observing.
Before my coffee, I checked a few hazel leaves for more leaf-mining moths and came across the distinctive gallery mine of the tiny micro moth caterpillar Stigmella microtheriella. When studied closely, you can note that the larvae starts as a tiny caterpillar, but as it eats its way around the leaf it puts on weight and the track it cuts becomes considerably wider, before the larvae emerge from the leaf to pupate in leaf litter. Fascinating to observe.
Over coffee I looked back at my notes to see what had been recorded and, with the high temperature, I was slightly surprised not to have encountered a butterfly or dragonfly. But with such a fine array of wildlife witnessed, I mustn't grumble.