For the last nine years I have surveyed breeding populations of farmland birds on a square kilometre of green belt on the southern fringe of Cambridge, to assess the levels of the biodiversity of an area close to the city.
Over the nine years I have in total recorded 91 bird species. These include 17 of the 18 farmland bird indicator species for the Sustainable Development Strategy, of which 14 have bred, and 18 red list species of high conservation concern, of which 10 have bred. My most recent survey of the area – which you can download below – showed exceptional numbers of grey partridge in the autumn (right) and corn bunting (above), as well as good numbers of skylark (below left), linnet, yellowhammer (below centre) and yellow wagtail (below right). Grey partridge declined by 92% between 1970 and 2013 and corn bunting by 89% while yellow wagtail declined by 67%, skylark by 59%, yellowhammer by 56% and linnet by 55%.
In 2020 the area supported a grey partridge population of at least 15 spring pairs/km2 and 92 birds/km2 in autumn. The arable farms typical of Cambridgeshire support between 0 and 5 pairs/km2 and 0–20 birds/km2 in the autumn.
Corn buntings also did particularly well in 2020, with 10 pairs. This is an important population – there are just 11,000 birds in the UK and its recent extinction in Ireland risks being repeated in large parts of Britain if its breeding sites are not protected.
In addition, the site supports thriving populations of water voles – in Hobsons Brook and the ditch that runs alongside the cycle path – and at least 20 brown hare.
In 2020 I also surveyed butterfly populations in the area and recorded brimstone, brown argos (below left), comma, common blue, Essex skipper, gatekeeper, green-veined white, holly blue, large skipper, large white, meadow brown, orange tip, painted lady, peacock, red admiral, ringlet, small copper (below centre), small heath (below right), small tortoiseshell, small white and speckled wood.
You can download a copy of my report for 2020 here:
My report for 2019 is here:
My report for 2018 is here:
My report for 2017 is here:
My reports for 2016 are here:
My reports for 2015 are here: