The British Trust for Ornithology (BTO) is carrying out a national wintering and breeding bird atlas during 2007-2011 covering the whole of Britain and Ireland. To coincide with the national Atlas the KOS is organising a county-wide Tetrad Atlas which is very similar to the BTO Atlas except that it is being carried out at a tetrad (2 x 2 km square) level, so is more detailed than the BTO Atlas.

This section of the KOS website has two main purposes – firstly, to show results and coverage for the current Atlas so far at a species and tetrad level and, secondly, to provide a permanent on-line archive of this Atlas and also previous county bird atlases. This will be the first time that maps for the current and previous county-wide bird distribution surveys have been available together and on-line.

Previous county atlases have been carried out as follows:

Breeding Season

1967-73 with results and maps published in the Birds of Kent (D W Taylor, D L Davenport and J J M Flegg 1981)

1988-94 with results and maps published in the 1996 Kent Bird Report (A C B Henderson and T N Hodge 1998)

Winter Season

1977/78-1979/80 with the results and maps published by the KOS as a stand alone Winter Bird Survey Report (N Tardival 1984)

Fourth Winter Season Starts

The final year of the four year BTO Bird Atlas begins on November 1st 2010. This new section of the KOS website is a substantial addition to the website, and as well as providing a permanent archive of this and previous atlases, it is hoped it will also act as a spur to more KOS members to contribute to the Atlas. There is still a lot of additional coverage needed if the Atlas is going to accurately map the numbers and distribution of birds in the county.

One issue yet to be resolved is the timescale for the current KOS tetrad atlas. Whilst the BTO Atlas is a fixed four year length, the KOS does have the option to extend tetrad level coverage for a further year or more. Previous county breeding atlases were both extended to cover a seven year period to ensure full coverage, but it is very unlikely that we will wish to do that for the current Atlas. The ideal would be to finish it within the same four year period as the BTO Atlas; whether this is possible depends entirely on the willingness of KOS members to help fill in gaps in coverage during the next 12 months.

If you are able to help but haven’t yet taken part in the Atlas I would be pleased if you could give me (Tim Hodge) a call on 01843 836259 and I can suggest the best ways in which you could help, and discuss what you need to do to be able to access the BTO Atlas website and enter your results.


Atlas Maps Added to KOS Website

To compile the Atlas section of the KOS website has involved pulling together various different survey datasets at relatively short notice, and there are likely to be some queries arising from this exercise. It is still a work in progress.

In particular, please note that the 1977/78-1979/80 Winter Bird Survey data has never before been computerised, so we have had to start from scratch in doing so. This exercise has not yet been completed, so only some maps are currently available. Further maps will be posted in due course to complete this part of the website, but it is likely to be several months before all maps for the previous Winter Bird Survey are on line.

Please also note that the maps giving the results for the two previous breeding bird survey results aggregate all probable and confirmed breeding records into confirmed breeding, as per the practice used in the 1988-94 breeding bird survey maps. It is considered that at a tetrad level this provides a more accurate picture of the status of breeding birds in the county. However, in the current Atlas the data so far being displayed in the maps uses four categories instead of two (Confirmed breeding, Probable breeding, Possible breeding and Other, which relates to migrants, flyovers and records of species entered into the system but without a breeding code). Thus the current map presentation reflects the data as entered into the BTO Atlas survey. It is likely that, for comparison purposes at a county level, the practice of combining probable and confirmed breeding will continue, but that this will be dealt with at a later stage.

If you do have any queries, please do not hesitate to contact me.