Posted: Tuesday 8th May 2018 by Twheatear
Adding to knowledge, both local and national...
This is the time of year when nearly three thousand people, all across the UK, go for a short early-morning walk, concentrating very hard. They/we are doing the fieldwork for the BTO's Breeding Bird Survey (BBS), which has been recording the state of our bird populations since 1994.
Each surveyor walks a prescribed route of 1 or 2 kilometres through an Ordnance Survey grid square, recording every individual bird they see or - the majority - hear. No doubt there are surveyors who can do that instinctively, but I suspect I'm in the majority in finding the required concentration pretty hard. My own 45 minute route through typical Marches countryside involves identifying and recording over 150 individual birds. By repeating the walk twice - typically in May and June - an estimate of the total number of adult birds available for breeding can be obtained.
All the data from the surveys are collected and analysed by the BTO. Their annual reports discuss national and regional trends. Many studies of individual species or habitats are also based on the survey data. In the past couple of years these have included papers on curlew, climate change, upland farmland and agri-enviroment schemes.
This is the third year I've done the survey and it's remarkable how quickly you get to know the area and the birds that live there. After its calls drowned out everything else in 2017, I was worried not to have recorded “my” green woodpecker this year, but there it was at the bottom of the ant-hill field. A flock of goldfinches is always in the same clump of trees, house sparrows and goldcrests have their regular places too. Sadly the lesser spotted woodpecker I recorded on my very first survey visit hasn’t been a regular. And, as usual, there were a couple of near-misses: the bullfinch just outside the square and the willow warbler that started singing on my way back to the car. Better luck next month!