Hope Farm Bird Monitoring Results 2022/2023

Today’s blog by Duerden Cormack, Monitoring Assistant, gives us the latest results for their winter bird count at Hope Farm, Cambridge.

The winter of 2022/2023 has been cold but sunny and very dry with no significant rain on the farm until after our counts had finished in February. This created great conditions for surveying (frozen ground, good light, and little wind), but was much to the dismay of Sophie who has been trying to keep recently replanted trees in our agroforestry trial alive!

To monitor our wintering birds, a team of volunteers conducted surveys on one morning in each of December, January and February. We used a whole area count method, where the farm is divided up into different areas and each is covered by an individual surveyor. All birds using the farm were recorded and mapped which allowed the total number of birds of each species using the farm to be calculated from the collated field maps.

Corn Bunting photographed on our January 2023 winter count

This winter we had some record breaking counts and in total recorded 6574 birds of 52 species including 15 of the 16 possible Farmland Bird Index species. This represents a dramatic improvement on the original surveys conducted in the winter of 2000/2001 when the RSPB first took on ownership of Hope Farm. In that winter 1178 birds of 32 species were recorded over the three surveys including just 9 of the 16 possible Farmland Bird Index species (see table 1).

Table 1: Comparison of Hope Farm winter counts for Farmland Bird Index species.

Winter Bird Index

Using these counts we produce a Winter Bird Index for RSPB Hope Farm which gives a measure of the average change in the numbers of these 16 species. For 2022/2023 the Hope Farm Winter Bird Index reached 25.21 compared to the baseline of 1 in 2000/2001 (see Figure 1). This equates to an average increase of 1326%. This is our highest index yet and it is great to see a strong recovery after the dip between 2017/18 and 2020/21.

Highs of Corn Bunting

The highlight of our winter count, and a strong driver of the increase in our winter bird index, was a record count of Corn Buntings. Compared to the previous high of 22 recorded in February 2020, we recorded 128 in December 2022 with a single flock of 110 favouring Field 5. A section of this field, in poorer condition following on from an old trial, was too thick with grass weeds to justify putting it to harvest.

Instead, we took it out of production in May 2022 and put in a summer cover crop of radishes, linseed, mustard, and phacelia that was then left throughout the winter. In September 2022, following on from a harvest of winter wheat where the stubble was cut high, the rest of the field was direct drilled with a similar mix. Drilling these covers contributed to our Soils SFI standard payments at £40/ha across the whole farm.

Due to the droughty conditions, the second mix didn’t establish so well but what we ended up with was a stubble with various cover crops and height structures, with broadleaves – some of which had seeds – and a few volunteers and grass weeds too. As well as Corn Buntings, this field hosted many Skylarks (53), Linnets (93), and Grey Partridge (22), and because the cover crop kept the ground relatively warm and wet, was also favoured by Snipe (16).

In late December, however, hard frosts brought most of this vegetation down to the ground and the large Corn Bunting flock left us. This is typical of Corn Buntings which can roam widely in winter, moving on when food supplies are depleted.

RSPB Hope Farm Field 5 in December 2022

Winter bird seed mixes

Bird seed mixes and supplementary feeding then became essential to close the late winter “hungry gap”. The winter bird seed mixes, funded as AB9 options in our mid-tier stewardship (£640/ha in 2022, profit £332/ha), were drilled in May with Oakbank’s Corn Bunting Mix, Farmland Bird Mix, and King’s Crops Wild Songbird Seed and Basic Wild Bird Seed mixes.

These were drilled together to provide a wide variety of seeds (white millet, sunflowers, radishes, phacelia, gold of pleasure, triticale, spring barley, quinoa, and a bit of red clover) in the hope that they would be palatable to a wide range of farmland birds. Again, the droughty conditions meant that these mixes didn’t grow as well as we’d have liked.

This made supplementary feed all the more important. We provided this under the AB12 option in countryside stewardship, where we are funded to spread 0.5t seed for every 2ha of AB9 (payment £657/t, profit £116). We spread between 60 – 120kg of seed (a mixture of home-saved wheat, red or white millet, canary grass, and home-saved oilseed rape) twice a week in three areas, depending on need.

On the January and February counts, numbers of birds were highest in areas that had supplementary feed, bird seed mix, and adjacent hedgerow for shelter and cover from predators. It was great to see record high numbers of Linnet (733), and good counts of Yellowhammer, Skylark, and Grey Partridge. We even managed to hold on to some Corn Buntings throughout the winter (20 in January and 15 in February).

With birds starting to sing, and our first spring migrant Chiffchaffs and Blackcaps arriving on the farm, it will soon be time to start our summer monitoring. Hopefully the nature-friendly actions described above have left our wintering birds in good condition for a productive breeding season and fingers crossed some Corn Buntings stay to breed!

Continue reading

• Carbon and agroforestry at Hope Farm - new project underway
• Drivers of songbird territory numbers in hedgerows at RSPB Hope Farm
• National insect week: growing cover crops for insects

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