Breeding Bird Survey 2008

As a participant in the Breeding Bird Survey I received a copy of the analysed data for 2008 in the post this week.  It makes fascinating reading - as always.  I'll pick out a few of the highlights, but first some history.

The UK, but particularly England, has been well off for information on trends in breeding bird numbers for decades.  The BTO's Common Birds Census was set up in the early 1960s after a couple of hard winters and worries over the impacts of agriculture on birds, and did a fantastic job in compiling information on common birds.  The data were collected by volunteers who visited a self-chosen site early in the morning on several days through the spring and summer.  All bird were mapped and then experts at the BTO would pore over the maps and assess the number of territories of all species. Then you stitch all the results together across the country and you have a picture of trends in numbers.

The CBC was set up in the early 1960s after a couple of hard winters knocked bird populations down, and in response to concerns about the impacts of agriculture.  The data were collected by volunteers who visited self-selected sites on about half a dozen early mornings through spring and summer.  Then BTO experts pored over the maps and assessed the number of territories for that site and year.  And then all the data were stitched together to come up with a picture for the country as a whole.

The CBC was a great scheme when it was set up, a world leader, but after three decades it was showing its age.  Its main drawbacks were that it was very time-demanding on volunteers and staff alike, most sites were in south-east England, the habitat coverage was restricted to woods and farmland, and there were worries about how representative the sites were of the countryside as a whole.  That sounds like a long list of problems but each was a niggle rather than a deal-breaker and so it took a lot of thought before the decision was made to start a new scheme - the Breeding Bird Survey.

The RSPB never had any formal involvement in the CBC but we played an important part in the birth of the BBS. As major users of the data we felt that the time had come to revamp the recording scheme and invested our time and money in the development of the BTO/JNCC/RSPB Breeding Bird Survey.  The RSPB remains a major funder of the scheme which now is based on two volunteer visits to over 3,200 randomly chosen 1km squares across the whole of the UK.  Although breaking with the past was hard, after planning it carefully, we've never looked back.

In the current report I find pages 8 and 9 fascinating - and they give information about the scheme rather than about the birds!  There was a dip in the otherwise strong growth in coverage in 2008 (probably because of the start of the BTO/SOC/BWI Atlas fieldwork) but the geographic spread of sites covered is incredibly impressive and now means that regional results can be compiled in a way that would not have been possible with the CBC. 

My eye always tends to look to the trends of farmland birds - for 2007-2008 I was surprised to see a mixed picture of mostly small increases and decreases. I would have expected that the first year without set-aside would have seen a drop in overall numbers but perhaps the substantial drop in 2007 meant that a further immediate fall was unlikely. 

The big movers, up or down, in the BBS stakes since its inception in 1995 are Canada and greylag geese (both doubled in numbers), red kite (quadrupled!), ring-necked parakeet (7-fold increase!), great-spotted woodpecker (doubled), stonechat (trebled) and yellow wagtail (almost halved), wood warbler, willow tit and turtle dove (all more than halved). 

There is a story behind each of these big changes, and I may come back to some in future, but the one that caught my eye was stonechat - largely because I don't live in a part of the country that has breeding stonechats and so have little personal experience of the trends over time.  The stonechat is increasing in numbers in Scotland, Wales and England.  Is this another species benefitting from climate change?  Certainly stonechats are much commoner in farmland in France and Spain than they are in this country.  But to have more stonechats on our coastal heathlands and along the moorland edge is a great prospect.  These chirpy little birds, with their sharp 'chack!' calls, are delightful.  Let's not forget that some species are doing OK whilst we fight to get a better deal for those which aren't.

If you'd like to participate in the BBS then please do contact the BTO - your efforts will be greatly appreciated by the RSPB and BTO and will be used by us and the governments of the UK to form part of the picture of the state of the UK's birds.  And many thanks to Kate Risely who is the BBS National Organiser!