The first two years of atlas surveying are indicating distribution changes from twenty years ago, some of which reflect known national trends, others perhaps not anticipated. The tentative conclusions here are based on records that have not yet been validated and on two years' only - things may change with two more seasons' data! More records are needed, especially confirmation of breeding, to strengthen the data and underpin future conservation work.
The indications are that Berkshire may have lost Wood Warbler, Tree Sparrow and Hawfinch as breeding species and Willow Tit and Snipe are almost gone. Breeding evidence for any of these species would be welcomed.
On the other hand, Little Egret, Red Kite, Herring and Lesser Black-backed Gulls, Peregrine and Dartford Warbler have started breeding in Berkshire since 1989.
A number of farmland species have declined in their distribution, disappearing from much of the lower land: Grey Partridge, Turtle Dove, Corn Bunting, Yellow Wagtail and to a lesser extent, Yellowhammer (disappearing in the east) and Reed Bunting. There is some indication that Reed Bunting and Yellow Wagtail are becoming more abundant on the Downs, but more breeding data are needed to confirm this.
The national declines in several woodland species are reflected in the Berkshire data: Lesser Spotted Woodpecker, Spotted Flycatcher, Marsh Tit (disappearing in the east of the County).
Other species which may be declining that we are keen for more breeding information on are: Teal, Redshank, House Martin, Tree Pipit (have they really disappeared from SU57?), Nightingale, Grasshopper Warbler, Garden Warbler, Lesser Whitethroat, Lesser Redpoll. Willow Warbler is nationally declining in the south of its range - there are widespread records of singing birds in Berkshire, making it a common "possible" breeder, but stronger evidence of breeding in few tetrads: can we firm up on breeding evidence for this species?
On the positive side, in addition to the new breeders listed above, there appear to be as many species whose ranges are expanding in Berkshire as there are declining species: Egyptian Goose, Shelduck, Gadwall, Mandarin, Cormorant, Buzzard, Hobby, Stone Curlew, Curlew, Black-headed Gull, Common Tern, Ring-necked Parakeet, Woodlark, Stonechat, Cetti's Warbler, Firecrest.
The provisional distribution maps are at www.berksoc.org.uk/atlas/maps/atlas.html. Please help us build a full and accurate atlas by submitting your evidence of breeding for any species, but especially those listed here, via the BTO's Atlas or Birdtrack pages.
Renton Righelato, Birds of Berkshire Atlas Group, March 2010