This ten-year study measured changes in the abundance of farmland birds on land managed under bird-focused lower- and higher-tier agri-environment schemes, as well as land no bird-friendly farming initiatives.

Under the higher-tier scheme, an average of 11% of the farm was devoted to bird-friendly measures, whereas <4% was managed under the lower-tier schemes. The authors specifically studied bird-friendly measures that provide seed-rich habitat for winter foraging, insect-rich habitat for feeding chicks, and nesting habitat for ground nesting species such as Lapwing. Higher-tier farms also received bespoke one-to-one management advice prior to the start of their agreements.

The results showed that when approximately 10% of a farm was devoted to bird-friendly farming practices under the higher-tier scheme, this benefitted over half of the farmland bird species in two of the three study regions. Although lower-tier provision generally failed to increase bird numbers, it helped to sustain populations of some species, which continued to decline in the absence of agri-environment support elsewhere.

The second part of the study asked what proportion of the farmed landscape would need to be placed into higher-tier agreements to recover farmland birds by 10% over ten years. The answer was similar in the two regions – 26% in the pastoral West Midlands and 31% in arable East Anglia.

https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.14338