2022 Summer Monitoring blog from Hope Farm

Duerden Cormack, Monitoring Assistant at RSPB Hope Farm, reflects on the key findings of the core monitoring of breeding birds, butterflies, and bumblebees carried out at Hope Farm during the summer months of 2022.

Reed Bunting at Hope Farm. Image (c) D Cormack

As was the case across much of the country, 2022 at RSPB Hope Farm was characterised by heatwaves and drought. Our local weather station recorded just 183.4mm of precipitation between January and July. To put that into perspective, only three years have experienced lower rainfall in the same period since monitoring began in 1961. On top of this, the average highest temperature between April and July (the crop growing season) was the highest since monitoring began. As well as the challenges this weather posed to growing food and turning a profit – most dramatically a wildfire that spread from a neighbouring farm – there were concerns that these extreme conditions might negatively affect wildlife. In this blog we will focus on our findings from the core monitoring of breeding birds, butterflies, and bumblebees. To find out more about our cropping and farm management, click here for an account of the 2022 growing season.

Birds

To monitor breeding birds at Hope Farm we use the BTO’s Common Bird Census methodology.  In 2022 this entailed 20 dawn starts between March and July to cover the entire 180ha farm 10 times. The behaviour and location of breeding species are recorded on visit maps which can then be collated into individual maps for each species at the end of the season. This allows us to analyse the maps using the BTO CBC guidelines to calculate how many territories were held on the farm by each species.
In total 527 territories of 41 species were recorded in 2022 including 15 of the 17 Hope Farm Breeding Bird Index species. When the RSPB took on ownership of Hope Farm in 2000, 301 territories of 35 species were recorded including just 10 of the 17 index species (Table 1).

Table 1. Territory numbers of Hope Farm Breeding Bird Index species 

Using these counts we produce a Breeding Bird Index for RSPB Hope Farm which gives a measure of the average change in the number of territories held by these 17 species. For 2022/2023 the Hope Farm Breeding Bird Index reached 2.49 compared to the baseline of 1 in 2000/2001 (Figure 1).

Figure 1.The Hope Farm Breeding Bird Index

A pair of Corn Buntings held territory on the farm and an additional pair were present just outside our boundary. This is a good result for an infrequent farm breeder and after the record count in winter 2022/2023 we are keeping our fingers crossed for a productive year for this species (Hope Farm winter monitoring results). Lapwings held territory for the sixth consecutive year with three pairs present. In contrast to previous years when they have made use of a Lapwing plot, they appeared to favour Field 10 which had been direct drilled with Spring Barley and has several wide flower margin strips running through it as part of an ASSIST trial.

Overall, the emerging trend is one of stable equilibrium. Nature-friendly farming has increased Hope Farm’s Breeding Bird Index by an average of 177% around which the index now fluctuates. Such fluctuations have many drivers including regional weather patterns, climate change, local and regional habitat modifications, as well as competition and predation. However, consistent recovery in the Breeding Bird Index after small dips suggests that populations are resilient and carrying capacity is now far beyond the level it was at when we took over the farm.

Butterflies

Three UK Butterfly Monitoring Scheme transects were surveyed for the 21st year at Hope Farm. Surveys were conducted weekly from 14th April (when minimum weather requirements were met) to 23rd September and all data was submitted to Butterfly Conservation for their national monitoring efforts. In total, 4506 butterflies of 25 species were recorded including records numbers of Gatekeeper, an increase in Common Blue, an encouraging sign after last year's dip (summer monitoring blog 2021), and a sighting of the uncommon migrant Clouded Yellow.

The Hope Farm Butterfly Index now sits at 3.35 compared to the baseline of 1 in 2001 – equivalent to a 398% average increase (Figure 2). Despite the drought and heatwave there has been a modest recovery following a dip in the index in 2021 and the trend of long-term growth continues. It is likely that nature friendly farming actions such as floristically enhanced field margins alleviate some of the negative effects of poor weather conditions, however, there is no escaping climate change, and it will be interesting to see how butterfly populations at Hope Farm respond as the region becomes hotter and drier.

Figure 2. The Hope Farm Butterfly Index 2001-2021

Marbled White on Knapweed. Image (c) G Bray

Bees

To monitor bees at RSPB Hope Farm we use Bumblebee Conservation’s BeeWalk methodology and aim to walk our transect once a month between March and October. Unfortunately, in 2022, we lost contact with our control farm – used to compare our results to – and fewer surveys than normal were completed. Although Figure 3 could suggest a decline in bumblebee numbers, it is likely that this is an artefact of low sampling effort and isn’t necessarily reflective of bumblebee abundance on the farm. In 2023 we hope to carry out a full season of surveys to better understand how bees are responding to nature friendly farming management actions.

Figure 3.

Conclusion

Despite the tough conditions, the wildlife covered by our core monitoring efforts seemed to fare well. As is true of climate change effects at larger scale, there are likely to be some winners and some losers and the effects of 2022’s extreme weather may not become apparent until following years. (This is where long-term monitoring is really valuable). Summer monitoring for 2023 is already well under way here at Hope Farm. Yellowhammers, Reed Buntings, and Skylarks are singing, and summer migrants are starting to return. You can follow our progress through @FarmWildlifeUK or #RSPBHopeFarm on Twitter.

Acknowledgements

Thank you very much to all the volunteers who gave their time to help out on the farm in 2022. Special thanks go to Rod Newbery who covered butterfly monitoring transects when Derek had Covid, broke his toe, and went on holiday (not all at the same time!).

Yellowhammer at Hope Farm. Image: (c) D Cormack