Today’s blog by Derek Gruar, RSPB’s Senior Research Assistant, gives us the latest results for the Winter Bird Index at Hope Farm, Cambridge.
The winter of 2019/20 has been characterised by the mild, wet and often stormy weather. Here at RSPB Hope Farm we have had plenty of rain and the waterlogged soil has prevented establishment of much of our winter cropping a situation many farmers are facing across the country. We were interested if these conditions would affect the number of birds on the farm.
To monitor the wintering bird populations our intrepid team of surveyors braved extremely muddy conditions on the fields. With surveys conducted on one morning in each of December, January and February they recorded all the birds using Hope Farm. I then post-survey interpret all our field maps to calculate a figure for the total number of birds for each species observed on the farm for that mornings survey.
Goldfinch, yellowhammer, linnet, reed bunting and chaffinch feeding flock (c) Derek Gruar
This winter we had an impressive number of birds on our three surveys with a total of 6962 individuals of 54 species observed. This compares more than favourably to the original surveys carried out when RSPB first took ownership of Hope Farm 20 years ago. In that first winter (2000/01) only 1178 birds of 32 species were recorded over the three surveys.
We recorded all 16 of the UK Farmland Bird Index Species on at least one survey compared to just 7 on the original surveys. Table 1 (below) gives a comparison of the 2019/20 and 2000/01 totals for Index species.
Table 1: Comparison of Hope Farm winter counts for Farm Index Species.
Using these counts we produce a Winter Farm Bird Index for RSPB Hope Farm, this gives a measure of the average change in the numbers of these 16 species. For 2019/20 the Hope Farm Winter Bird Index is now 13.87 (Figure 1) compared to the baseline of 1 in 2000/01. This equates to an average increase of 1287% in the wintering numbers across this suite of species. At times the place does seem to be alive with birds.
The index graph shows an upward trend of more birds using the farm in each winter. Birds are attracted to Hope Farm because we provide winter food in sown plots of seeding plants left for the birds, our hedgerows that are cut on a 3-year staggered rotation provide dense cover and increased volume of berries for food and within our fields we have over-winter cover crops between harvest and sowing of spring crops as this green cover over the winter improves soil quality and prevents soil erosion compared to leaving the field fallow. The biodiversity benefits of these cover crops are currently being investigated at Hope Farm.
Figure 1: Hope Farm Winter Bird Index 2019/20.
Other highlights of these surveys included record counts for the red-listed (over 50% national population decline in 40 years) farmland seed-eaters Linnet (440) and Corn Bunting (22) and after a winter away we were delighted by the return of a small number of Tree Sparrows attracted to an area of unharvested Millet crop. Waders were also very evident this winter with Snipe, Woodcock, Lapwing and Golden Plover all seen and a fly-over Teal was a new species for the farm and added to the adage that it has indeed been “Nice weather for ducks”.
With many birds now starting to sing, our summer monitoring will begin in late-March/early-April and we await how the soggy winter has affected our breeding bird numbers next summer.
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