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.


Construction work on HS2 Phase One is due to commence in 2018, with completion scheduled for 2026. HS2 crosses the BOS area from Brackley to Southam via Chipping Warden. Read more ...

Birding the Steppes and Mountains of Central Asia - Alan Peters

Kazakhstan is a vast country which borders Russia, China, Uzbekistan, the Kyrgyz Republic and Turkmenistan. Mainly steppe, it is sparsely populated, the main settlements being concentrated in the south eastern corner of the republic where the plains give way to the Altai and Tien Shan Mountains. Read more ...

A survey of breeding birds, conducted using 3 visits over 3 months to a random 1km square. Read more ...

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