I am a bit of a sucker for surveys which combine my two hobbies of walking and bird identification. So when the River Thame Conservation Trust contacted me about a bird survey in the Thame catchment, I signed up. The purpose is to understand the freshwater habitats and species of the catchment and to monitor changes in them.
I have been given a tetrad (two-kilometre square) on the edge of the study area some distance from the River Thame. It is in the Wormsley valley near Stokenchurch (SU79H, with the grid reference SU7294 in the bottom left-hand corner). I covered this tetrad for the British Trust for Ornithology (BTO) bird atlas in 2009-10, and was particularly thrilled to see a crossbill here in February 2010. So I hoped to do so again.
The survey methodology is similar to that of the bird atlas. You walk through your tetrad for two or three hours, four times in the year, taking in a range of habitats and recording everything you see or hear. We are asked to start about half an hour after dawn. You then record the findings on the BTO’s birdtrack.
So I set off at about 8.30am last Saturday from Cowleaze Wood car-park, about a mile north of Christmas Common in Oxfordshire. Masses of chaffinches flew up from the ground into the beech trees, very difficult to count. I heard a nuthatch and jay and immediately saw three red kites.
The Vale of Oxford was a pale mist beyond the Chiltern escarpment.
I had to leave my tetrad briefly so stopped the clock. I got back into it on the bridleway approaching Lower Vicar’s Farm in the bottom of the Wormsley Valley. Redwings flew across the track, feeding on the copious berries. There were lots more kites but I didn’t want to double count so I was a bit cautious about the numbers, recording 14.
The pond at the farm is a bit stagnant, and it looked like a sparrowhawk had been there.
The bridleway is a dead end at the Buckinghamshire boundary beyond Lower Vicar’s. It is ridiculous that there is no definitive path along the bottom of the valley, and something to be investigated before 2026 when the map is closed to applications based on historical evidence (though I am pretty certain this has been tried before unsuccessfully).
I climbed up the hill on the footpath through an old maize crop where I saw 25 linnets. Some of them perched on the wires.
The view was lovely.
Then it was into the woods again, at first through young birch, then more mature trees, and then conifers. Cowleaze is owned by the Forestry Commission with public access. There were a lot of tits in the conifers, and I saw marsh, coal, blue and great tits, and heard goldcrests. It’s hard work looking up into the tops of the trees to identify birds.
I spent a bit of time near where I had seen the crossbill seven years ago, crazy really but you never know!
It is a shame that the adjoining mature beechwood has no public access, it looks so inviting.
I had some time left over and so I walked on access land on the other side of the Christmas Common road, looking across to Bald Hill. This was a completely different habitat. I saw more redwings here.
My total was 25 species. When I entered my 81 chaffinches (probably an underestimate) on the BTO website it challenged me in red letters, saying ‘unusually high bird-count’. I find that odd, but I confirmed it.