Monday, 21 March 2011

Which are the most important breeding species in Lincs: Insights from BBS

The Breeding Bird Survey (BBS) is an annual survey which monitors changes in bird populations from year to year and trends over longer periods. It started in 1994 and took over from the Common Bird Census. Its big virtue is that it is based on randomly selected 1 km squares across all counties of the UK. It therefore provides a more accurate estimate of populations. The BBS is used for important conservation purposes such as determining red, amber or green conservation status. In 2009 volunteers surveyed a total of 3,243 squares across the UK of which 51 were in Lincolnshire.

All the data is available to anyone who wants to access it by country, region or county at this link:

There are 2 sets of data: first the number of squares each species has been recorded in, by year in each geographic area, second, the total numbers of each species counted by year in each geographic area. You can copy and paste the data into excel and analyse it as you wish.
So I've been messing about with the data to answer the question above. From the conservation point of view; which are the relatively most important species of conservation concern in Lincolnshire compared to the rest of the UK? I took the data and computed the rate of occurrence for all species I believe have bred or probably bred in Lincolnshire in the last 10 years and expressed that as a percentage of the rate of occurrence across the UK as a whole. Species occurring at a rate of 50%greater than the rest of the UK were designated as important in Lincolnshire. The conservation status (red or amber) of each species was noted from the RSPB Birds of Conservation Concern 2010 Report (available on their website).

Birds of conservation concern status is determined by the rate of fall of populations as measured by BBS and the atlas from the early 70s to 2009. So some relatively abundant birds like Skylark and House Sparrow are red because they are much less abundant than they used to be because of pressures arising from our industrial civilisation. Here is the list of species generated from this analysis.

The general UK trend of population change is also shown. It is possible that if we had a larger sample of BBS squares in Lincolnshire there could well be more rarer species on the list.
But the point is these birds are the jewels in our crown and we can make a better contribution to the overall UK conservation of these species by our efforts in Lincolnshire.
How can we do that. First by making sure that we record these species as confirmed breeders in as many squares as possible in the final season of the breeding atlas. Second by contributing to BBS and helping monitor annual changes in the populations of these birds. Third by supporting and lobbying for measures that contribute to the breeding success of these species through schemes like habitat management on Lincolnshire nature reserves and in the wider countryside, and the provision of nest boxes for those species which use them.
If you'd like take part in BBS which is primarily conducted in April and May have a look at and the more atlas roving records you can submit that confirm breeding for the above species, where they've not been confirmed so far, the better.
Look out for more posts about these individual species over the next few months.

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