Saving the cirl bunting from extinction in the UK

Author: Lynne Roberts

A desperate situation

The cirl bunting is the UK’s rarest farmland bird. Having once been widespread in southern England and Wales, the UK population of cirl buntings suffered a dramatic decline from a peak in the 1930s. In 1989, a national survey recorded just 118 pairs, mostly in the south of Devon.

Urgent action was desperately needed to prevent the extinction of the cirl bunting in the UK as a breeding bird.

By 1989 the cirl bunting population had contracted to a small area in south Devon (pink area). Male cirl bunting (left); female cirl bunting (right). Images: Andy Hay – rspb-images.com

The rapid changes in farming practices in the second half of the last century particularly impacted the cirl bunting, which is an extremely sedentary species. Cirl buntings need all their year-round feeding and nesting requirements close together, since they only move around 2 km between breeding and wintering areas and are thus heavily reliant on diverse mixed-farming systems providing a mosaic of habitats.

The decline in traditional mixed-farming practices led to the loss of closely situated invertebrate-rich grasslands and overwinter stubbles rich in arable plants – both key foraging habitats for the species.

How the needs of cirl buntings can be delivered

The habitat needs of cirl buntings can be met through implementing elements of Farm Wildlife’s six key  actions, which outlines how key farmland habitats and practices can be managed to help wildlife thrive. They benefit particularly from the following elements of the Farm Wildlife approach:

Action for cirl buntings

In the early 1990s, the Cirl Bunting Project (a joint project run by the RSPB and Natural England) was set up with the aim of saving the cirl bunting from extinction in the UK.

This could only be achieved through working with farmers and landowners to improve and increase the area of suitable habitat in the birds’ remaining range in South Devon.

Cirl buntings had clung on here because there was still mixed farming and research initiated in the late 1980s highlighted how important spring barley left as stubble was for winter feeding. As a result, a bespoke option (spring barley left as winter stubble) aimed at cirl buntings was made available within the original Countryside Stewardship scheme.

Over-wintered stubble is an important food source for cirl buntings and other farmland birds. Image: Cath Jeffs

Many willing and enthusiastic farmers and landowners became involved in managing the land more sympathetically to support the needs of the cirl bunting and, importantly, continued or started to grow spring barley. They also carried out other beneficial work, such as providing dense hedgerows with scruffy edges, pockets of scrub and rough grassland, using further agri-environmental scheme options to help support these activities.

‘RSPB first encouraged us to farm in a way that might encourage the cirl buntings and other birds. We are now organic and since 1990 when we entered the Countryside Stewardship Scheme we have seen a dramatic improvement in habitat and species – the cirl has certainly benefited. Going forward I hope that farmers will use less pesticides and we find more ways of feeding the growing population in a wildlife friendly way.’

Geoff Sayers, Noss Mayo

Success!

The Cirl Bunting Project has been a great success and is one of the UK’s best farmland species recovery stories.

By 2009, The National Cirl Bunting Survey (RSPB/Natural England) recorded 862 territories, with some range expansion, and in 2016 a milestone of over 1,000 pairs was reached – an amazing result that was way beyond expectations at the start of the project when the aim was to stop them being lost as a breeding species from the UK.

By 2016 an impressive increase in the range of the cirl bunting population had been achieved
Cirl bunting population increase between 1989 and 2016

Monitoring has shown that the population increase has been achieved by habitat management delivered by farmers mainly through agri-environment schemes.

‘We have loved being part of this success story. Very satisfying, and we will look forward to getting more cirl buntings on our land and further afield – hopefully!’

Sue Hadow, Blackawton, Totnes

Wider benefits

The arable management implemented to benefit the cirl bunting is also contributing to the conservation of threatened arable plants. During farm site visits, Cirl Bunting Project staff noted species such as Broad-fruited corn salad, Weasel’s snout and Field woundwort and some of the cirl bunting farms were found to have assemblages of arable plants which are of national importance.

The broad-leaved weeds most beneficial to birds are generally not the highly competitive ones. Their presence within a crop is dependent on low-input cultivation, and less productive soils are ideal for this type of management. Over-wintered stubble will allow some arable plants to set seed and will supplement the spilt grain as winter food for seed-eating birds such as finches, yellowhammers and corn buntings.

Arable plant seedlings in a spring barley crop. Image: Lynne Roberts

Lessons from the project

The project showed that the changes the farmers implemented in south Devon created the right habitat mosaic for cirl buntings and other wildlife to thrive. Initially, the focus centred on the cirl bunting’s remaining haunts, but as the project developed it moved on to creating stepping-stones of habitat to draw birds into new areas. This helped the species to spread and has given the once fragmented population more security.

Although farmers were creating habitat at a farm level, they were working as part of a landscape-scale project, which is why it has been so successful. Each farmer contributed a piece of the jigsaw vital to safeguarding the species.

As the people at the heart of the project, the farmers and landowners needed the right support to manage the land sympathetically for wildlife. They required agri-environment schemes which could be practically integrated into their farming systems, with advice and help on the ground to implement scheme options and ensure that the benefits could be sustained.

The legacy of nearly 30 years of the Cirl Bunting Project

The legacy of the Cirl Bunting Project is the continued survival of the cirl bunting in the UK, but the project has also shown that well-supported and practical agri-environment schemes, alongside engaged farmers, are vital to ensuring that wildlife and viable farming can co-exist.

Cirl buntings remain on the IUCN Red List and are classed as ‘Vulnerable’. If support for the right changes to farming practices is not there and agriculture intensifies again in the area, or the right balance of mixed-farming habitats is not maintained, cirl buntings and the other wildlife that has benefitted could be in trouble once more.

‘I feel very privileged to have been part of the cirl bunting project from the outset, and have hosted several people hoping to spot a cirl bunting. I will carry on the conservation work on my farm as long as I can.’

Edward Baker, South Allington

Further information on the cirl bunting story

Find out more about cirl buntings here.

More information on the Cirl Bunting Project can be found here and on the Cirl Bunting Action Hub, which is funded by Action for Birds in England, a conservation partnership between Natural England and the RSPB, with further support from the Rare Breeding Birds Panel (RBBP).

If you would like further information on how your farm could be part of the Cirl Bunting Project in South Devon, please contact Cath Jeffs (cath.jeffs@rspb.org.uk).

New research: What limits bumblebee populations on farmland?

Authors: Dr Tom Timberlake and Prof Jane Memmott 

A new study by Tom Timberlake and colleagues at the University of Bristol shows how important late summer flowers and rural gardens can be for supporting bumblebees on UK farmland.

Does this offer an opportunity to devise more targeted agri-environment schemes for pollinators?

Pollen and nectar are the main source of food for bees, including the charismatic and agriculturally important bumblebee. It is no surprise then that declining flower densities – particularly on farmland – are considered one of the most important drivers of pollinator decline. Agri-environment schemes which incentivise the planting of wildflower strips and the expansion of semi-natural flowering habitats such as hedgerows and field margins are an important tool for reversing pollinator declines, but are they really the most efficient way of supporting pollinators?

Image 1: For bumblebees like this one (Bombus terrestris), it’s not just about how much food is available, it’s also when that food is available through the year. A dandelion flowering in early spring for example, would be more valuable to a bumblebee than an equivalent flower in mid-summer.
Image: T. Timberlake

Whilst agri-environment schemes have successfully increased the overall numbers of flowers on farmland, they tend to overlook the timing of when these flowers are available to pollinators. Different plants flower at different times and most of the plants in agri-environment schemes flower in late spring and early summer which often isn’t the period of greatest need for pollinators. Pollinators need a continuous supply of food throughout their flight season, and for species with long flight seasons such as bumblebees, this means from late February, right through until October. ‘Hunger gaps’ of even one week could limit the number of pollinators surviving through the year.

Hunger gaps

To support pollinators in the most effective and cost-efficient way, it makes sense to find out when these hunger gaps occur and then devise targeted management or planting schemes to plug these gaps. A previous study by our team did just this and showed that nectar supplies on farmland were most limited in early spring (March) and late summer.

To check what effect these ‘hunger gaps’ were having on bumblebee populations, we carried out a study on 12 farms around the west of England. We captured, recorded and released hundreds of bumblebees and then measured all sorts of features of the farms to find out which aspects of the farm were most important in determining bumblebee density.

To our surprise, the supply of nectar in late summer (September) was by far the most important factor driving bumblebee density on these farms – more so even than the amount of natural habitat. Late summer is a very important stage in the lifecycle of bumblebees – it is when new queens are produced and must pile on the pounds before their winter hibernation. A rich supply of flowers is therefore crucial, but with fewer and fewer hay meadows, cover crops and weedy areas to provide this late summer nectar on farmland, bumblebees are struggling.

Image 2: Low nectar supplies in late summer coincide with an important stage in the colony lifecycle, limiting colony density the following year. How might we change the shape of this curve to reduce the September bottleneck?

How to plug the gap

So what can we do to plug this late-summer hunger gap on farmland and support bumblebees? On our farms at least, ivy was the most important plant for providing nectar during this sparse time, so managing your hedgerows and woodland edges to promote this amazing plant is a good first step. Leaving some rough weedy corners for late flowering species like thistles, knapweed, scabious and dandelions can also contribute to plugging the gap.

We found that Environmental Stewardship Scheme pollen and nectar mixes were really effective at increasing overall nectar supplies but were far more effective when mown early, or in multiple phases, to extend flowering into the late summer.

Finally, if you want to give those hungry queen bumblebees a real treat in the run-up to autumn, a tasty cover crop of late-flowering red clover would do just the trick. A single hectare of this crop could provide around 1 kilogram of raw nectar sugar each day and completely close the late summer gap.

There was one final surprise in our results… Small patches of garden were having a significant influence on the density of bumblebees. Farms with more gardens had more bumblebee colonies.

Gardens have a far denser and more diverse supply of flowers than farmland and are often managed to keep things flowering throughout the whole year. These little floral oases seem to be throwing bumblebees a lifeline during periods when farmland offers very little.

Image 3: Species which flower in September such as dandelions, red clover, ivy and thistles (clockwise from top left) are likely to be disproportionately important to bumblebees and other pollinators. Including these and other late-flowering species in conservation schemes will help fill the late summer hunger gap.
Images: T. Timberlake & Wikimedia Commons

How much and when

The take home message is that it’s not just about how much food we provide for pollinators, it’s also about when that food is available through the year.

Providing more flowers in the early spring and late summer when bumblebees are at their hungriest is a great way to support these important creatures.

Image 4: Some examples of low quality (left) and high quality (right) farmland habitats for pollinators. The more diverse and flower-rich high quality habitats tend to provide a more consistent supply of nectar through the year, helping to fill those important hunger gaps.
Image: Nick Tew

This article is the summary of a University of Bristol-led research paper published by Thomas Timberlake, Jane Memmott, Ian Vaughan and Mathilde Baude in the Journal of Applied Ecology. The work was funded by the Natural Environment Research Council (NERC) with additional support from the NERC Biomolecular Analysis Facility.

Case Study: Managing Farmland for Grey Long-eared Bats

Author: Craig Dunton, Grey long-eared bat Project Officer, Bat Conservation Trust

Species: Grey Long-eared bat:

© Craig Dunton/www.bats.org.uk

 

Why is farmland important for this species?

With as few as 1000 individuals In the UK, the grey long-eared bat is one of our rarest mammals. Their distribution is restricted to the southern coast (Devon, Dorset, Somerset, Hampshire, Isle of Wight and Sussex) and there are only 9 known maternity colonies; meaning that this species is on the brink of extinction in this country. Currently, work is being carried out to conserve this species as part of 'Back from the Brink' – a Heritage Lottery funded conservation project aiming to save 20 species from extinction. https://naturebftb.co.uk/

Farmland is vitally important to all bat species. 70% of land in the UK is used for agriculture, so for very mobile species that utilise the whole landscape, farming practices can have significant impacts on bat populations. Some bat species are more resilient than others, but for those that have very low populations, are particularly sensitive to light and disturbance, and have very specific habitat requirements, there are significant threats to their survival.

Like all bats, the grey long-eared bat needs some key elements throughout its range in order to survive and thrive.

Roosts: Bats utilise a wide variety of structures to roost in, as their requirements change throughout the year. Roosts are needed for different activities – hibernation roosts, maternity roosts, night feeding roosts (for some bats) – these are all needed at different times of the year, and different bat species choose different structures for different activities.

Many bats hibernate underground, using caves, mines, cellars and tunnels that have a cool and constant temperature that bats need to hibernate. Many farms have these types of features, so it is important to be aware of their importance for bats. Some bats roost in a variety of different tree features; cracks, splits, woodpecker holes, loose bark – so it is important to retain trees that have ‘interesting’ features.

Grey long-eared bats are mostly associated with man-made roosts – usually the roof spaces of large, traditional, stone buildings with slate roofs. There are some records of them using caves and rock crevices, but no records of them using bat boxes in England.

Many buildings on farms can provide important roosts for grey long-eared bats, particularly large stone buildings with slate roofs and large, open roof voids. These can provide vital maternity roosts, temporary day and night roosts and opportunities for hibernation. As all bat species are protected, if you are planning to carry out any work that might impact bats or their roosts, the National Bat Helpline will point you in the right direction, please email enquiries@bats.org.uk

Foraging sites: As with roosts, different species of bats have different types of habitats that they favour for foraging. All UK bat species are insectivores, and depending on their size, flight habits and other physical adaptations, different species need different insect prey and therefore different habitats for foraging in. Greater horseshoe bats are large bats and so favour large prey, particularly around the maternity period. Cockchafers and dung beetles are their food of choice. Daubenton’s bats are often seen foraging over water, trawling insects from the surface of the water with their specially adapted, large hairy feet.

© Craig Dunton/www.bats.org.uk

Grey long-eared bats have a close association with unimproved lowland grassland and riparian (wet) habitats such as meadows and marshes.

Managing permanent pasture more extensively with very low or no inputs will benefit grey long-eared bat populations, offering more opportunities for invertebrates including the moths and craneflies that grey long-eared bats favour. Managing land to maintain or increase species diversity (more flowering plants) as well as structural diversity (a range in sward height), will give insects food and shelter resources. If possible, consider transitioning land back to hay meadow management as opposed to silage production, as this allows insects and plants to complete life cycles and thrive.

In terms of cultivated land, increase pollen and nectar plots and wildflower margins, and manage by cutting or grazing to maintain plant diversity. These areas alongside trees and tall hedgerows have proven benefits for some bat species. Minimise pesticide use and consider crops that contain lots of flowering plants such as herbal leys.  Within arable land, conservation headlands or low input cereals can be beneficial if management results in increased invertebrate numbers. These are all ways of increasing foraging opportunities on less productive areas of land for grey long-eared (and other) bats.

Farming organically has many advantages, including huge benefits to biodiversity, natural resource protection and reducing greenhouse gas emissions. Following organic principles should be considered if aiming to encourage bats and other biodiversity.

Connectivity: For so much of our wildlife, good habitat connectivity is critically important. Linear features in the landscape such as hedgerows, watercourses and ditches, enable different species to flow freely through the landscape, enabling opportunities for feeding, interacting and breeding. For bats, good connectivity is vital, as many bats use linear features to navigate through the landscape, using their echolocation to move from roosting sites to foraging sites. When these features are well managed, they can also provide foraging opportunities as well as providing obvious features to allow free movement. Extensive hedgerow management (2-3 year cutting cycle) allows hedgerow plants to flower and fruit, providing vital resources for insects. Buffer strips along streams and rivers not only provides increased opportunities for foraging, but can also protect watercourses from nutrient and pesticide run off, protecting aquatic flora and fauna.

For more information on land management for grey long-eared bats contact Craig Dunton (Grey long-eared bat project officer) on cdunton@bats.org.uk