Clyde Valley Waders - Developing new approaches to wader conservation on farmland

Guest blog by Dan Brown, Senior Conservation Advisor, RSPB Scotland

The sharp declines in breeding wader populations continue despite almost 2 decades of agri-environment schemes.

The first five years of my career were spent helping to “target” the schemes - coordinating surveys between farms, volunteers, agricultural agents and those that hold the purse strings - to ensure agri-environment funding and management flowed to the farms with the birds. But with continuing declines, an ever-increasing list of questions were being asked by ourselves and the agricultural partners we are working with.

Do all the management options benefit the birds? If so, is enough land managed under agri-environment? What impact are badgers and other predators having? How many nests are lost to farming operations? What aspects of farming systems are intrinsically good for the birds?

Finding answers

With these questions in mind, in 2018 RSPB staff and volunteers started monitoring nests with the support of the farmers. We scan fields weekly from roadsides and enter when we spot incubating birds. Once located, nests have small temperature recording devices hidden under the lining - allowing us to see what time nests fail or hatch. We also use trail cameras and these offer a snapshot of what predators take nests, how livestock interact with incubating birds, and how nesting birds respond to farming operations.

By the end of 2022 we had monitored around 450 nests across 30 farms. Over the same period, the local SAC office organised 3 wader-focussed meetings per year. This provided the basis to meet regularly, share data and discuss issues with farmers - helping develop consensus. And this knowledge sharing led to the development of some management trials.

Management trials

We found that the most popular agri-environment option for waders in Scotland does not benefit the birds in terms of hatching success. When compared to conventional/ normal pastures, pastures grazed under 'Wader grazed grassland' have similarly low levels of hatching success. (Some important caveats exist – most of the farms in the area graze these fields at the 1 livestock/ hectare sub-option - as opposed to the 6 week livestock exclusion option. It could be that on any farms operating a 6 week stock exclusion in other parts of Scotland, hatching success is higher…)

We also monitored nests managed under 'Wader and wildlife mown grassland' - the agri-environment option for hay and silage fields. Nests fared much better with around 50% hatching. Nests on arable land also fared much better - at nearly 40%.

Total nest survival between 2018 and 2022 across a selection of farm habitats and management regimes.

There are a few factors that might account for this difference between habitats and management regimes.

Importance of livestock

We note that farmyard manure – which is spread on silage fields but typically not spread on agri-environment pastures – appears attractive for nesting. It could help camouflage nests and build soil organic matter, thus benefitting invertebrate prey. Some of our trials have therefore encouraged the early spreading of straw-y dung, to see if it can attract birds. Other studies have explored the important role liming can play on increasing earthworm densities - so there is probably something there too.

However, perhaps the overwhelming factor explaining why nests on agri-environment silage do much better than nests on nearby pastures is the lack of livestock during the peak nesting period. We have found that nests on habitats without livestock do twice as well as nests in habitats with livestock. Our results are remarkably similar to a study that looked at lapwing hatching success at coastal marshes in relation to livestock.

Our trail camera footage offers some explanations. Livestock are often curious of incubating birds and clutches. They can move eggs and accidentally trample them. We suspect they sometimes chew them but contrary to other studies we have little evidence to suggest they actually eat them. But perhaps more important is the frequent disturbance they cause. In response, alarm calling and swooping from birds probably alerts nearby predators, and creates windows of opportunity for them to swoop in while incubating birds are off the nest.
Any discussion around the negative impacts of livestock during nesting is within the context of the beneficial impacts of livestock farming systems for waders.

Livestock systems are massively important for waders, supporting most of the UK breeding populations. Overall, waders are hugely reliant on livestock grazing systems. Hence, we are working together through the Clyde Valley Wader Initiative to trial changes that can work for both the birds and the farmers. One such trial has been looking at brassica management for lapwing.

Image: Lapwing chick hiding in one of the trial brassica plots (c) Ed Tooth

We found many nests on brassica stubbles in 2022 and through nest marking and experienced contractors, the nests did well despite being converted to grass and arable silage in late April and early May.

But nest marking is onerous and cannot be undertaken at scale. So several farmers at this point took matters into their own hands and established brassica crops in the summer of 2022 and agreed to leave the stubbles in the spring. On some farms, these were the first crops grown in decades.

Fantastic results

The result in 2023 was stunning, with lapwing hatching success just shy of 80% across 6 plots - night and day compared to what we had recorded previously. Poached brassica stubbles probably create ideal conditions for camouflage and coupled with minimal disturbance this may explain the high rates of hatching success. As the regen in the stubble grew, a pair of curlews laid a replacement clutch in one of the trial plots, and it also hatched. It was also noteworthy how often curlews were foraging in the plots. Diversification of upland farming landscape through bringing back crops looks like a winner for lots of upland biodiversity.

We are repeating the trial this year. Participating farms have already got their crops in the ground and are free to graze it when and how they wish. It is early days but there doesn’t appear to be a need for any particular brassica crop (i.e. kale, rape, fodder neeps) and both cattle or sheep can graze it down – we have observed high hatching success under most brassica management regimes.

Image: Lapwing nest in brassica stubble (c) Dan Brown

Future plans 

If similar results occur in 2024, then the partnership will advocate for a new agri-environment option to support this management. Many farms will be open to integrating 4-5 ha brassica plots into their system and recognise the business benefits. The challenge arises from the reduced spring grazing available by leaving the plot fallow, and any future option would need to compensate farmers for this. (The slightly delayed establishment of the follow-on grass sward or 2nd year brassica crop has not emerged as a potential issue).

Of course, boosting hatching success needs to go alongside sustainable levels of chick survival. Our future plans include better monitoring of the chicks. We have learned that broods will spend the first couple of weeks in the regenerating stubble, before moving to adjacent grazed pastures with wet features. Keeping track of broods within taller areas of cover is challenging, but something we hope to spend more time undertaking in the future.

We also urgently need to trial new approaches to pasture management to improve hatching success on this key habitat. Based on our observations and data so far, our best guess is such management would likely involve spreading some dung and then keeping livestock out of trial fields for several weeks. It might also be useful to trial deterrents to keep birds away from laying their first clutches in fields that will have lots of livestock introduced in April. There are also some ideas around rotating the management of pastures to avoid nests in the same places year on year (i.e. easy for predators).

Working in partnership 

There is a long way to go yet. But through working together in partnership and designing management trials together, we hope to develop more effective agri-environment options for the future.

In recent years the monitoring work conducted in the Clyde Valley Wader Initiative has been supported by the Biodiversity Challenge Fund and Working for Waders, whilst the brassica trial plots have been supported by NatureScot. The farmer meetings have been supported by the Rural Innovation Support Service.