February can be a good time to catch up with Lesser Spotted Woodpeckers, if you are lucky enough still to be able to find them in your area. The spring call is distinctive and it is so much easier to see the bird when there are no leaves on the trees. The species is associated with open woodland – especially open oak woods and orchards. Dead trees and decaying branches provide soft timber in which to build nests and search for food.
Lesser Spotted Woodpeckers have been disappearing for years. In the period of the BTO’s Common Birds Census we lost 60% between 1968 and 1999. More have been lost since but, sadly, the BTO/JNCC/RSPB Breeding Bird Survey cannot give us a figure; the species is just too scarce now. Reports came in from only 33 of the 3239 squares surveyed by BBS volunteers in 2010.
Bird Atlas 2007-11 provided a great opportunity to produce an up-to-date picture of the distributions of every British species. 70% of the tetrads (2km by 2km squares) of Great Britain were visited during the project, which amounts to 50 times the area visited by BBS volunteers, and we are eagerly awaiting the finalisation of the validated maps.
To whet the appetite, Simon Gillings and Dawn Balmer have produced current versions for Lesser Spotted Woodpecker.
There is still validation work to be done in several parts of the country so these maps are for illustrative purposes only.
Presented below are the winter map for 1981-84 and the provisional winter map for 2007-11, which clearly show major changes in just twenty-five years.
Breeding Season - A history lesson
For the breeding season, the Atlas Team has a complicated story to try to get across, because there are three sets of data to combine within one picture. How can they show the changes across the period of the three surveys – 1968-72, 1988-91 and 2008-11 – and the current distribution? The map below, for Lesser Spotted Woodpecker, provides an early insight.
The solid salmon colour shows the areas in which Lesser Spotted Woodpeckers were found in all three surveys, while the lighter salmon colour indicates where it was found in the first and third periods but not in the middle one.
Soild triangles show recent changes, with black downwards-pointing ones indicating that the species was found in the ten-kilometre square in 1988-91 but not this time around. By contrast, orange upwards triangles indicate where it was found for the first time in the 2008-11 survey. Sadly there are very few of these orange triangles for Lesser Spotted Woodpecker.
Open triangles remind us of previously-known changes. Black downwards-pointing ones indicate that the species was found in the ten-kilometre square in 1968-72 but not in the other two periods. Orange upward-pointing triangles show squares in which birds were first found in 1998-91 and where they are still present.
In tabular form
|Light salmon||Present||Not detected||Present|
|Solid up triangle||Not detected||Not detected||Present|
|Open up triangle||Not detected||Present||Present|
|Solid down triangle||Present||Present||Not detected|
|Open down triangle||Present||Not detected||Not detected|
The Atlas Working Group is delighted that Simon Gillings has been able to sort out a way to show so much information in one map. As many people will have seen in the latest Atlas Newsletter (PDF, 5.35 MB), typically there will be up to seven maps for each double-page spread for a resident species. As well as this historical change map for the breeding season, there will be up-to-date winter and breeding season distributions, a winter change map and maps of relative abundance and/or changes in relative abundance.
The colours used in the map are being developed for the book; when shown on a computer screen they may not appear as they will on paper. We are considering how to develop the best versions for internet use.
For our most widely distributed species, the Breeding Bird Survey gives us a picture of annual fluctuations in numbers and hints about longer-term changes in distribution. Having coverage for 3239 one-kilometre squares is great but even 5000 survey squares would be insuffcient to monitor changes in number for Lesser Spotted Woodpecker.
Bird Atlas projects are scheduled for every twenty years but birdwatchers can help to check what happens between now and 2027 by submitting their bird records to BirdTrack. See the Lesser Spotted Woodpecker records sent in so far for 2012.