Over the past year FWAG SouthWest have been working on an innovative project in partnership with Suntory Beverage and Food GB&I, the makers of Ribena, to undertake monitoring of birds on several of their blackcurrant farms. 

FWAG, and particularly Senior Farm Environment Adviser Rebecca Mills, have a long history working with many of these farms, developing a programme of actions to achieve environmental good practice alongside fruit production. More recently, this has supported the development of an initiative focussed on key farmland habitats and species protection including hedgerows, grass buffers, green headlands, farmland birds, pollen and nectar sources and mature trees. 

Now, this monitoring project is looking to build on the success of work carried out over the past 5 years by gathering quantitative data on key bird species and working to support and promote their presence on blackcurrant farms. 

There are of course several methods and approaches to surveying birds on farm and each has their merits. But for the purposes of this project, where the aim has been to develop a baseline of species present on the farm across the year, we have turned to more novel technologies. 

The process

Small bioacoustic recorders were deployed within different habitats. The advantage of these is that they can be left out for several weeks in all weathers and as a result help to record a thorough snapshot of bird song from that location. They can be configured to record at different times of the day, for example around the early morning dawn chorus and around sunset, and at a frequency that is likely to pick up species if they are present, but does not result in thousands of sound files to then analyse. They take three AA batteries and are attached to a hedge, tree or fence post. The difficult part is remembering to take coordinates of where you left them! 

The files are then downloaded off the memory card and we use a piece of sound analysis software to process the files and turn them into one full length sound file. Then, the exciting bit. This file is analysed using a classifier called BirdNet which scans the recording and matches any bird song it detects to a known species. This means that analysing several hours of recordings can take less than an hour. A confidence level can be set so that you know the recorder is only picking up species it is highly likely were there and minimises the risk of returning false positives. We also manually check and confirm any dubious detections in addition to a random sub-sample to help maintain accuracy in the process.

   

 Above left, Oliver Edmonds checking the recorder and above right, a recorder in place.

The software produces a full species list for that recording and then you can start to tease apart any differences between habitats or times of year. This is a more economical way to capture a good baseline of bird species over large areas of farmland, and across a full year, than more traditional survey methods. These other methods of course are still very important, particularly if wanting more detailed abundance data on bird populations or bird behaviours e.g. are birds breeding at a particular location? And surveys such as the Big Farmland Bird Count serve as useful comparisons and help to add to the richness of data collected on farm. 

But this project on the blackcurrant farms has really helped to demonstrate the merits of the use of bioacoustic recorders as we have been able to capture a larger species list than previously recorded. This has included the presence of quieter and more elusive species including those which are more unusual. The project has also detected 15 threatened UK red list bird species. 

Particularly notable species that were detected are hawfinch, firecrest, yellowhammer, tree pipit, mistle thrush and spotted flycatcher. It is encouraging to see that key farmland birds such as linnet and skylark are being recorded alongside dunnock and bullfinch, the latter which may be being supported by the sympathetic hedgerow management advocated under the scheme.  A good diversity of species was also detected in and around the cropped areas. 

Having this knowledge of what birds may be present on the farm can help inform decisions around farm and habitat management and any interventions that may be needed to support target species. Birds are useful indicators of habitat and ecosystem health and changes in species over time can be picked up quickly through this sort of monitoring. 

Going forward, the bird survey baseline can be compared against future monitoring to see if the habitats are still supporting these species and whether actions such as those delivered through the Ribena growers Farm Stewardship initiative with Suntory GB&I continue to support rich bird assemblages.