Field Event Reports

20 May: A visit to Warburg BBOWT Nature Reserve

There were good daylight views of a Badger.

A group of eight members arrived at the BBOWT Warburg Reserve at 2 pm, Sunday 20th May having negotiated two miles of the twisty, bumpy and single-lane road taking us into the wilds of the Chilterns through Bix Bottom. While the small car park was full, the Site Warden, Giles Alder, had anticipated this and kindly guided us into an area behind the Site Office. We were greeted by our host Nick Hards and an associate Roger Golding, both members of the British Pteridological Society. Nick introduced us to the targets of the day and kindly gave us all a map of the Reserve, a leaflet on 'The Private Life of Ferns' and an identification pamphlet 'What's that Fern'. The planning that Nick had done for this visit became even clearer when it was apparent that he had made three research trips to the Reserve so our visit was very focussed.

Our first stop was just a few yards from the car park where Nick showed us small specimens of Wall-rue and Rusty-back Fern tucked in the crevices of a dry-stone wall. Nick pointed out that it was becoming less easy to find 'Wall Ferns', as for example in Oxford the need for 'tidiness' meant many had been cleaned off walls.

We then turned into a track that led immediately into the woods. All the woods on our visit were dominated by Beech, occasional Oak and small stands of Ash (the latter often looking somewhat 'sick' - possibly Ash Dieback?). In the initial stages of the walk the understorey was dominated by Bracken, with patches of Woodruff, odoriferous Ramsons and scatterings of Herb Robert and Yellow Archangel. On our first stop the fern flora was dominated by clusters of the Male Fern, where we also found Broad Buckler-fern and Golden-scaled Male-fern.

Worth mentioning at this point (without going into the copious detail conveyed) that at every stop Nick explained the intricacies of species identification, their morphology, reproduction and ecology. At one stop it was explained that the Dryopteris affinis aggregate contains four or more species in Britain and Ireland depending on which schema is followed. One system defines affinis, borreri, cambrensis and pseudodisjuncta as species. Previously these were defined as either subspecies or morphotypes of affinis. They are further subdivisions! A key reason that Roger had joined the walk was that he is an expert on this Dryopteris affinis aggregate (known as 'scaly male-ferns') and he often ventured into the masses of Golden-scaled Male-fern looking for other species in the aggregate.

On our next stop we discovered the Narrow Buckler-fern and Lady Fern, as well as other previously seen species. We now walked higher up into the woods, where there were patches of now-over Bluebells and green swathes of Dog's Mercury. A number of specimens of the fungus Daldinia concentrica (King Alfred's Cakes/Cramp Balls) were found on the track. The hunt was on to find Borrer's Scaly Male-fern (Dryopteris borreri) one of the 'affinis agg', which Nick had discovered previously, but despite a search none were found. Our final find in the woods was the Hard Shield Fern. We then left the lower woods crossed the dry grassland zones (where some Early Purple Orchids were seen by some) to find our last two main targets. The first, a number of Bird's Nest Orchids were discovered poking their colourless heads out of the woodland leaf litter - a first for a number of attendees. The second target needed quite a hunt in a damp, lush meadow above the woods. Finally hiding deep in the sward there were the single simple oval leaves of Adders Tongue Ferns, a couple with the stalked spore-bearing spikes. Nick told us this was a very primitive fern (even by fern standards) and had the highest number of chromosomes of any plant.

So the day was done. Well not quite! A shout went up 'Badger' and there on the edge of the wood was a young Badger poking its head through the netting. Everyone froze. The Badger tested the air, entered the grassland, snuffled through the dense foliage (often disappearing from view) and finally joined four of our group beside the ferns. It then sniffed the boots of our host Nick, before, in no rush, ambled back to the woods, where it took off at speed.

The group then stumbled back down hill in a happy mood to the car park. The final bonus came in the wildflower garden at the rear of the centre where two orchids were shown to us by Giles: some slightly over Common Bladderwort and diminutive Fly Orchids in full flower. These capped a pleasant three-hour walk on a fine day, with expert and dedicated leaders. Few birds were seen, rather heard the cronking calls of Raven, the 'kick kick' of a Great Spotted Woodpecker and repetitive 'zip-zap' of several Chiffchaffs. Thanks were conveyed to Nick and Roger for hosting the trip and to Giles for making the visit possible. Three cars then left for the challenging road from Bix Bottom.

Graham Bateman

Ferns Identified:
Wall-rue (Asplenium ruta-muraria)
Rusty-back Fern (Asplenium ceterach)
Bracken (Pteridium aquilinum)
Male Fern (Dryopteris filix-mas)
Broad Buckler-fern (Dryopteris dilatata)
Golden-scaled Male-fern (Dryopteris affinis agg)
Narrow Buckler-fern (Dryopteris carthusiana)
Lady Fern (Athyrium filix-femina)
Hard Shield Fern (Polystichum aculeatum)
Adder's Tongue (Ophioglossum vulgatum)
Orchids Identified:
Birds Nest Orchid (Neottia nidus-avis)
Common Twayblade (Listera ovata)
Bee Orchid (Ophrys apipfera)
Early Purple Orchid (Orchis mascula)
Fly Orchid (Ophrys insectifera)
Attendees:
Michael Bloom, Chris and Bridget Biggs, Sally Gillard, Jackie Hudson, Ursula White, Graham Bateman, John Killick.

APPENDIX

List of plant species recorded and notes provided by John Killick:
This is my list requested for ANS.

It is what I noted down on 20 May, mainly noting things I had seen newly in flower. It is incomplete, omitting all trees and some of the ferns, is a tiny fraction of what is in the Warburg reserve, and restricted to the route I took (including some grassy areas not traversed by the main group).

The numbers in the first column are those of the Biological Records Centre but I do not have all of these.

John Killick

John Killick

46 Ajuga reptans Bugle
75 Allium ursinum Ramsons
192 Asplenium ruta-muraria Wall-rue
211 Athyrium filix-femina Lady-fern
256 Briza media Quaking-grass
323 Campanula trachelium Nettle-leaved Bellflower
  Carex divulsa ?ssp leersii Leers' Sedge
  Dryopteris affinis agg Scaly Male-fern
  Dryopteris carthusiana Narrow Buckler-fern
661 Dryopteris dilatata Broad Buckler-fern
665 Dryopteris filix-mas Male-fern
764.1 Euphorbia amygdaloides amygd. Wood Spurge
838 Fragaria vesca Wild Strawberry
183 Galium odoratum Woodruff
687 Hyacinthoides nonscripta Bluebell
/862.2 Lamiastrum galeobdolon montanm Yellow Archangel
1130 Leontodon hispidus Rough Hawkbit
1173 Listera ovata Common Twayblade
1191 Lotus corniculatus Common Bird's-foot-trefoil
1202 Luzula campestris Field Wood-rush
1222 Lysimachia nummularia Creeping-Jenny
1263 Melica uniflora Wood Melick
1296 Milium effusum Wood Millet
1305 Moehringia trinervia Three-nerved Sandwort
1382 Ophrys apifera Bee Orchid
1596 Potentilla sterilis Barren Strawberry
1619 Pteridium aquilinum Bracken
1678 Rhinanthus minor Yellow-rattle
1729 Rubus idaeus Raspberry
1599 Sanguisorba minor minor Salad Burnet
1818 Sanicula europaea Sanicle
2168 Veronica chamaedrys Germander Speedwell
2172 Veronica montana Wood Speedwell

John Killick