The largest contiguous ancient woodland block in East Anglia, Hockley Woods sit astride the ‘southern Essex Alps’, a ridge of London Clay capped with sands and gravels, and have become a traditional fixture for Naturetrek day walks at this time of year, searching especially for one of our rarest butterflies, the Heath Fritillary. This year, I spent a couple of hours the previous day there with friends and this blog is an amalgam of the two days.

I am always worried by this trip. Given the butterflies have a short flying season of only three weeks or so, and that they can start as early as mid-May and as late as mid-June, there is no date that can guarantee sightings. Having said that I have never failed, but this year’s warm, droughty spring has brought things on a little early, so the fritillaries were numerous, but perhaps a little past their peak emergence date.

A very hot and humid spell meant that insects in general were more flighty than sometimes, but the number of insects was very noticeable. From the constant hum of Honeybees visiting Bramble flowers to the mini-swarms of flittering, feeding and flirting wood sprites, bioabundance was a joy to witness, especially given the relative dearth of insect life over the past couple of summers. Nature can bounce back quickly when conditions are right!

One reason why this site is so important for Heath Fritillary is the abundance of its larval food plant Common Cow-wheat in the coppices and rides. But apart from this, there were relatively few other plants in flower, the spring flush having now faded. Hedge Woundwort, Bush Vetch, Slender St. John’s-wort and Wood Avens were just a few of the relatively sparse flowers used to demonstrate some of the more distinctive plant families.

Thank goodness for the Bramble! Lining every ride-side and filling every gap in the leaf canopy, Bramble flowers were bursting forth and feeding all manner of insects, with bumblebees and Honeybees, and hoverfly and longhorn-beetle mimics of the stingers:

There was also a scattering of Common Figworts, with their beautiful if sombre flowers, and most showing signs of the associated Figwort Weevil – adults, spherical cocoons, slug-like larvae, and the grazed leaves.

Large Wood Ants’ nests are a real feature of the wood: it is unwise to stand too still for too long! The ants are everywhere, heaving, hauling and searching, as well as tending and milking the blackfly colonies on many a dock shoot. And one of the specialities of this wood, Four-spotted Leaf-beetle, a myrmicophilous species, inhabiting the ants’ nests, and known in Essex only from one other wood apart from the Hockley complex.

Oak (two species, plus hybrids), Hornbeam and Sweet Chestnut form the bulk of the woodland cover, but there are plenty of other species, some characteristic of spring-lines (Wild Cherry and Aspen), others very much restricted to ancient woodland site (Wild Service-tree, Woodland Hawthorn). And some with their own specialist leaf-feeders and gall-causers.

Deeper in the shade of the trees, birds were singing, especially Stock Doves, Blackcaps, Wrens, Chiffchaffs and Robins, calling Treecreepers, Nuthatches and Buzzards, and noisy bands of fledgling Great, Blue and Long-tailed Tits. Following spring drought, there were few fungi in evidence, but blue-stained wood infected by Chlorociboria aeruginascens was still to be found.

At the other end of the light/shade spectrum, a walk along the woodland edge produced singing Skylarks over the arable fields. Ox-eye Daisies were flowering and Salsify fruiting in the field margins, here a trues sense of place looking down from the lofty heights, over Southend, and across the Thames to the North Downs.

A selection of other insects from the walks included the bugs Closterotomus trivialis (a relative newcomer to the UK, first found only 15 years ago), Bracken Planthopper (despite the abundance of its foodplant, only four other recorded sites in south Essex), Common Damsel-bug and Red-legged Shield-bug.

And much more!

Despite us being in the depths of the ‘June Gap’, there were a few other butterflies around, including small numbers of Holly Blue, Speckled Wood, Red Admiral, Painted Lady, Comma, Small Tortoiseshell and Meadow Brown…

… but it was the fantastic fritillaries that stole the show: the primary reason for our visit and the main memory we shall take away from it. Hats off to Rochford District Council for striking such a good balance between human recreation and nature!