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These two Atlases have now been published:

NWalesBirds_Frontcover for web.gif

Have a look at the results of all the BTO national Atlases: Mapstore

The areas covered by the BTO representatives in North Wales (based on a map on the BTO website (


DA  Dave Anning

AB  Anne Brenchley

GG  Geoff Gibbs

IH  Ian Hawkins

MaO  Mel ab Owain

Local, or regional, atlases usually use the 'tetrad' as the recording unit. A tetrad is a square, 2 km x 2 km. The map, below, shows the tetrad SJ26N, which means that its western boundary is the easting 24 and the bottom boundary is northing 66 within the 100 km square SJ, so the tetrad includes the 1 km squares: SJ2466, SJ2467, SJ2566 and SJ2567.


Within each 10 km square there are 25 tetrads.

The CBRG and COS welcome receiving breeding season records with breeding codes, as used in the Atlas fieldwork, and listed below:

Possible breeding

01 H - Observed in suitable Habitat

02 S - Singing male

Probable breeding

03 P- Pair in suitable nesting habitat

04 T - Permanent Territory (defended for at least one week)

05 D - Courtship and Display

06 N - Visiting a probable Nest site

07 A - Agitated behaviour

08 I - Brood patch of Incubating bird (from bird in the hand)

09 B - Nest Building or excavating a nest hole

Confirmed breeding

10 DD - Distraction Display or injury feigning

11 UN - Used Nest or eggshells found from this season

12 FL- Recently FLedged young or downy young

13 ON - Adults entering or leaving nest site in circumstances indicating Occupied Nest

14 FF- Adult carrying Faecal sac or Food for young

15 NE - Nest containing Eggs

16 NY - Nest with Young seen or heard


Please enter these codes in the 'Activity' column in the spreadsheet or the relevant extra details form in BirdTrack.

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