The Winter Random Sqaure Survery (WRSS) as established in 1975 as a means to record the status of common species which are otherwise overlooked by our monthly recording system.

The WRSS is conducted in the last weekend of November and February, with results combined to produce the survey counts for that winter. Observers are allocated a 1km square at random from each of the 12 100km squares of the BOS survey area. Each observer is asked to record each species seen and estimate the total number of each species over a period of 2-3 hours. In most years we are able to field multiple observers per 100km square, thus increasing coverage.

Squares are not re-surveyed until all surveyable squares have been surveyed. Squares are omitted where there is limited or restricted access. To date we have conducted 2 complete surveys, from 1975-2000 (1120 squares, 93%) and 2000-2016 (658 squares, 55%).

The results from the first 3 years (1976-1978) are averaged to produce an index for each species, one for abundance and one for distribution. From that time onwards, a 3-year rolling index is calculated, which shows the relative abundance and distribution change for each species.

This enables the BOS to analyse species trends over a 40 year period. In general the trends match national findings, but there are significant differences which allows the BOS to better understand species which are fairing better or worse within our survey area. We use this information to adjust the conservation targets on our reserves and when providing guidance to local planning.

The results of the survey can be read in our book Birds of the Heart of England.

We need your help to find Swifts and their traditional nest sites in Anglican churches.  50 years ago most of our local parish churches had nesting Swifts.  Chris Mason brings us up-to-date  . . . Read more ...

(Please note the earlier time to maximise daylight.)

We will visit Compton Verney, CV35 9HZ, on the B4086 between Wellesbourne and Kineton. Read more ...

A survey where observers are each given a randomly selected 1km square and record species and numbers for a minimum period of 2 hours between 9am and noon. Read more ...


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