Saturday 12 May 2012

BBS - Carrying out the survey

There was a frost in rural North Wiltshire last night, but as I got up and made my way to my BBS square the sky was clear, the sun was shining and it was starting to warm up. This was to be my early visit, one of two visits to be made this season. I made two habitat and reconnaissance visits over the last bank holiday to set things up, but this was to be the survey proper.

My survey square is OS 1km grid square ST9880 2 miles north east of Christian Malford and maybe 5 miles north east of Chippenham. To the north it is bordered by the M4 motorway and to the south by the Great Western Railway and the remnants of the Wilts and Berks canal. The majority of the square is covered in arable fields and grassland, some of which is grazed by sheep. There is also one road, a smattering of residential and farm buildings, wooded hedgerows and a small stream.

Put simply, the aim of the survey is to record all species of birds and mammals seen or heard in the randomly allocated square. This is done by walking steadily along two 1km transect lines, split into five 200m sections, whilst recording species in four different range bands. Ideally the transect lines should be exactly 1km long, running exactly north/south or east/west and at 500m apart. In practice this is rarely achievable and so my transects followed the best path possible.

Walking my chosen transects took, in total, 88 minutes. I started at 06:58 and finished at 08:20. My records comprised of 25 bird species, including whitethroat, buzzard and green woodpecker, 6 rabbits, 2 roe deer and some unidentified bird or mammal pellets. They were likely to be barn/tawny owl or buzzard, but they did seem awfully large. Strangely I didn't take a picture at the time as I was so engrossed with carrying out the survey. More the fool me, there's a lesson to be learnt there.

I have planed my second visit, weather permitting, for June 16th.

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