Sunday 1 December 2019

Small Mammal Surveying in Bisham Woods

Bisham Woods, near Maidenhead, I’ve been discovering, is a highly varied collection of woods, from Goulding’s Wood in the south through Park Wood, Inkydown Wood up to Fultness Wood and Quarry Wood in the north. Turns out, the variety isn’t just confined to the names.
Over the course of 2019 we’ve conducted four trapping surveys and one nut hunt, at various places across the range. The woods are owned by the Woodland Trust who are interested in updating their records of what they have here, so these mammal surveys have been part of a larger survey being conducted into the whole range of flora and fauna which has ranged from “forest bugs” (a type of shield bug) to roe deer, with buzzards and a variety of woodpeckers along the way.
The southern end of the woodland has a large variety of trees, good understory, fallen trees, and other great hiding places for our small furry friends. The northern end is very much a beech wood with patches of brambles and the odd holy bush here and there but very little cover.
Human usage also seems markedly different. Quarry Wood has a bewildering array of footpaths with, ironically, the official Public Footpaths left almost unused, and nearly invisible in places! The southern end gets a share of human, and canine, visitors too, but much less, or at least it seems that way. Certainly fewer high-speed cyclists!

So, what did we find?
The four trapping events attempted to sample, approximately, a quarter of the woods each. Each event, we set 45 traps up in three locations across the section being surveyed. These had been decided on previously through recces of the area, looking for places with cover and food.
Between three and eight amazing volunteers from Wild Cookham, Wild Maidenhead and Berkshire Mammal Group, some with significant previous experience and others with none, dragged themselves along at ungodly hours of a Saturday morning to check and reset the Longworth traps, set out on the Friday evening; and then once again on the Saturday afternoon. Whatever the weather, and it was a bit damp underfoot on one or two occasions, or the slopes I had us clambering up and down.
On the very first event, in May in Park Wood, we were treated to a roe deer quite stubbornly standing her ground while we reset the traps. From her curious calls, and scratching at the ground, we concluded she had probably just given birth, so we made all haste to move on and not upset her further. I’ve also seen muntjac deer in this part of the woods previously, and their territorial marking spots were clearly present in several places.
A good collection of freshly excavated earth, especially in Goulding’s Wood, indicates a fairly healthy mole population, to go with the “Rocket Mice”. Apologies to those who now have that song ringing round their head, but the wood mice do seem to have bundles of energy and springs for legs; emerging from the traps like missiles! Unlike the rather more civilised, sedate, bank voles we’ve found. (Sorry, no pictures of them, my photography skills need to improve, but managed to get a couple of wood mice to pose nicely.)
Checking the traps in the morning and then again in the afternoon has produced a finding I had suspected, but not previously seen. Mornings are wood mice; afternoons are bank voles (roughly speaking).
The wood mice appeared to be slightly more nocturnal than the bank voles. Although we caught both species in the mornings and afternoons, the quantity varied consistently across all the trap sites, where we caught anything that is.
Quarry Wood proved surprising in this respect. The 45 traps we put out caught nothing! Well, apart from the odd slug! Even most of the footprint tunnels came back devoid of rodent evidence (and sadly no hedgehogs either). Slugs do like eating the paper though!
Apart from one site. A real curiosity, right at the southern end of Quarry Wood, bordering Fultness Wood, the footprint tunnels were crawling with rodent spoor, but the traps were untouched – even the slugs abandoned them!
Grey squirrels are pretty ubiquitous though. A typical walk through any part of the woods will have you almost tripping over them.
Our final event was a nut hunt in Inkydown Wood and Park Wood. Its not been a good year for the hazel trees in this area sadly and, whist we had a great crowd of twenty or so volunteers, we found very few nuts from this year. Plenty of older ones, but trying to identity, or frankly even find, teeth marks on an old, weathered, nut is an interesting challenge. All that said, we found plenty of, surprise surprise, squirrel-cracked nuts but also a number opened by rodents. It was hard to tell which though.
All-in-all, it’s been an interesting, educational, and useful year of surveying.

Many thanks are due to Reading University, for loaning the traps and tunnels, and the members of Wild Cookham, Wild Maidenhead and Berkshire Mammal Group, for their invaluable time and assistance.

Damian Carter
Surveys Officer, Berkshire Mammal Group