From the Society of Biology’s Science Policy weekly news update:

Key results

• The unsmoothed farmland bird population index for England, covering 19 species, decreased by 5 per cent between 2008 and 2009. The index is now at its lowest recorded value, at 53 per cent lower than its 1966 starting value.
• Twelve species (almost two-thirds of those included in the index) declined between 2008 and 2009 – Kestrel, Lapwing, Grey Partridge, Skylark, Starling, Greenfinch, Tree Sparrow, Yellow Wagtail, Linnet, Wood Pigeon, Corn Bunting and Rook. This decline was significant for the first six species listed. For many species, the decline between 2008 and 2009 is a continuation of downward trends evident over at least the last four or five years.
• Seven species increased between 2008 and 2009 – Goldfinch, Jackdaw, Reed Bunting, Stock Dove, Turtle Dove, Whitethroat and Yellowhammer. Most of these, for example Goldfinch and Jackdaw, have shown long-term upward trends.

Bird populations are considered to be a good indicator of the broad state of wildlife because birds occupy a wide range of habitats, they tend to be near or at the top of food chains and there is considerable long-term data on changes in bird populations which helps with the interpretation of shorter term fluctuations.

Further information.