Distribution Maps

Based on the data submitted in the first two years of surveys, we have prepared maps of the species richness of tetrads and the distributions of individual wintering and breeding species. These provide a guide to progress so far and gaps in the distributions for which we seek more information. Our thanks to all the people who have contributed to developing our distribution mapping resources, particularly Marek Walford, Nigel Wardell, Mike Taylor, John Swallow and Jason Righelato. The maps provided here are ©Birds of Berkshire Atlas Group.

Species Richness

Records have been submitted via the BTO for 382 of the 394 Berkshire tetrads. Timed visits have been made to two thirds of the tetrads, though in the time available not all species occupying the tetrad are recorded and roving records are a crucial supplement to the data.

Wintering Species

In Berkshire overall, 146 species were recorded as wintering during 2007/8 and/or 2008/9. Not surprisingly, the most watched areas prove to be the most species rich, with the record being held currently by SU97J (90 species), which includes the Jubilee River and Slough sewage farm, with SU67F in the Theale area, running up (83 species). Further records for the less watched areas would be expected to bring most tetrads up to at least 40 species in the winter.

Breeding species

In all, 182 species were recorded during the first two summer seasons of the Atlas programme. Of these some indication of breeding was noted for 138 species and 111 species were confirmed as breeders.

Confirmed Breeding Species 2008/9

However, the numbers of species confirmed as breeding in individual tetrads is, on average so far, very low, with the great majority of tetrads recording well below 25 species. We need to focus on breeding evidence for the next two breeding seasons to get an accurate picture of the birds breeding across the County: see the notes on increasing breeding status. For comparison, twenty years ago the Birds of Berkshire Atlas surveys found 120 "confirmed" breeding species across Berkshire. For individual tetrads, the median number of species with any evidence of breeding was 58, 30 of which were confirmed.

Renton Righelato - 18 March 2010