This presents the results of the 2016 survey in the same way as the 2006 survey, ie red squares where there are no sparrows, green where there are some, with the squares being 300m each side. In 2006 we did not have the advantage of the WGUS survey protocol, so we only took negative results from residents, not by surveying. In 2016 I was more confident of reporting null results from mobile surveys by surveying in the breeding season using the WGUS protocol. The increase in red squares reflects the change in methodology, rather than that something terrible has happened to the town's sparrows in the intervening decade. I made the assumption that if I didn't hear sparrows in the breeding season, they weren't there, so I distributed null results at 100m intervals along the corresponding part of the GPS tracks to feed into the mapping software.
The surveyed zone is split up into squares of an even size. Rather than the 2km x 2km tetrads normally used, which are a bit large in scale for the town and for the range of house sparrows, we have chosen to use smaller squares of 300m x 300m. The presence of sparrows observed in a square is shown by a green outline. A negative report for an area is shown by a red outline, unless there are positive reports of sparrows in the same square. Areas with no squares are unsurveyed.
the figure below shows the results of the 2006 survey on the same initial scale.
The sparrows in the hedge along the Grange Farm cycle path to Martlesham are still there, I did not log these in 2016.