The BTO Bird Atlas is on the go.
In 2007-8 I did two tetrads, TG22A and TG 42V.
In 2008-9 I’m doing TG02S
Those are the grid squares. Each survey requires a two hour walk recording all the birds you see, visiting all the main habitats in the 2x2km square. This is called a timed tetrad visit, or TTV. The winter survey requires a visit Nov-end Dec, then again in Jan- Feb. The spring survey, again two visits, is April – mid May and May to end July.
Results are being shown on line as they come in – http://www.bto.org.uk/birdatlas/