Mary Colwell, Mike Smart (Curlew Action), Rebecca Pringle (Natural England) with Dutch hosts Henk-Jan Ottens (Montagu’s Harrier Foundation), Gerrit Gerritsen (Birdfriendly Dairy)
SUMMARY OF FINDINGS
- The Netherlands has long devoted attention to “meadow birds” (ground-nesting waders, notably Black-tailed Godwit, Lapwing, Redshank, Ruff, and Curlew). One of the current leaders of the long-term research is Prof. Theunis Piersma of the University of Groningen. We were welcomed to Friesland by Theunis, which was our first port of call; you can access the blog about the visit here.
- Curlews do nest in some Dutch nature reserves, but they can survive in intensively farmed landscapes if certain conditions are met, namely sensitive mowing/harvesting regimes, nest fencing, minimal disturbance and wider protection from predators.
- A system of paid coordinators and a network of skilled volunteers increases hatching success. Individual nests are fenced, the chicks radio tagged and then (in silage areas) collected at mowing times to protect them. However, the majority are still lost to agriculture and high levels of predation – 60% in the first week.
- In silage areas, farmers require compensation for lost crops to buy in fodder, or, they want to be given access to other areas to mow.
- Locally distributed agri-payments reflect the local need better than a top-down, one-size-fits-all model. For the UK, how to distribute funding to coordinators and volunteers would be a challenge, as is how to set the level of payments.
- Curlews do better in arable fields than in silage, particularly if they have access to strips of long grass and insects.
- A number of chicks die from lack of insects in all areas. As the largest ground-nesting wader, Curlews may be more reliant on larger arthropod prey, such as grasshoppers and crickets, which are victims of intensive farming methods.
- Motivation and morale-boosting is important for volunteers as losses of birds continue to be high.
- Locally-led, culturally sensitive communication with farmers is vital.
- There is potential for ‘Meadow friendly’ or ‘Curlew friendly’ products like milk and cheese.
- Long-term studies like Gerrit Gerritsen’s project with Curlew in Overijssel, are vital to give a holistic picture of what is happening to populations in any one region.
- Producing conditions that allow fledging is still the limiting factor in Curlew recovery.
Arable field with indoor cattle shed + windmills. Mike Smart, Mary Colwell, Rebecca Pringle
There are few places less likely to support some of Europe’s most important populations of Curlews than the intensive landscape of the NE Netherlands. Most nest in areas that are vitally important for the dairy industry and for arable crops such as sugar beet, potatoes and maize. The land is dominated by vast, flat fields of monocultures interspersed with pockets of nature reserves. The soils of the area reflect the complexity of the landscape before land reclamation, namely marshland, peatland and heathland. Today, peat provides the richest agricultural soils. Curlews in the Netherlands, as across much of Europe, are subject to increasing pressures as the demands of modern farming clash with nature protection. Along with other ground-nesting birds such as Lapwing, Black-tailed Godwit, Short-eared Owl and Montagu’s Harrier, they are casualties of that on-going battle.
Location of north-eastern provinces of Friesland, Drenthe and Overijssel and density map of Curlew in the Netherlands
Freshly cut silage field with Storks foraging in the aftermath - Drenthe
The provinces we visited between 29th May to 2nd June 2023 were Friesland (few Curlews left), and the main Curlew areas of Drenthe and Overijssel (around 500 pairs between them). There are more nature reserves in Overijssel than in Drenthe (over 1000 hectares in Gerrit’s region alone), and large areas are not regularly monitored, such as the extensive marshy area of Weerribben-Wieden, a National Park in Overijssel, where numbers of Curlews appear healthy but recent figures are not known. The total Curlew population in the Netherlands is estimated to be between 3,800-4,800 pairs (based on a national survey in 2013-2015), ranking it as no 5 in the most important Curlew countries in Europe. This represents a reduction of around 50% over the last three decades. The present number may well be lower than this estimate as declines continue in most areas.
Weerribben-Wieden National Park
The following summarises our site visits in the provinces of Drenthe and Overijssel. Our hosts were Henk-Jan Ottens and colleagues Annemarie Loof and Albert Boer in Drenthe, and Gerrit Gerritsen in Overijssel.
DRENTHE AND GRASSLANDS
Our first site was a field near the village of Dwingeloo, a dairy farm that takes silage from permanent grassland. There are three nests in the farm’s fields (20 nests in the surrounding area) and each one is protected by an electric fence, erected by volunteers deployed by a paid coordinator and assisted by paid fieldworkers. The farmer is paid €100 euros per nest and is also paid to leave an unmown strip nearby to provide food and refuge for the chicks.
Uncut, fenced nesting site on left, strip of unmown grass on right
This is just one of the projects in the Drenthe province which have been working on Curlew for the last 5 years, and each area has the same system of paid coordinators and fieldworkers alongside volunteers. The scheme has a blended finance model, with funds coming from a combination of environmental organisations, individual donors and regional government. Albert Boers told us he applied for government funding every two years.
Curlew Action’s Mike Smart and Rebecca Pringle from Natural England with ecologist Henk-Jan (with aerial to locate radio-tagged chicks), and project leads Annemarie Loof and Albert Boers.
Volunteers are mainly retired people, but there are some young enthusiasts. Altogether, around 150 volunteers find around 100 nests each year and fence 60 of them. They start searching for returning birds from March onwards, sometimes using drones to find nests. Once located the nests are fenced before the first cut in early May. Results show that 75% of the fenced nests hatch chicks compared to 25% of the unfenced nests. After hatching the chicks are radio tagged and followed throughout the mowing season. As mowing is every 33 days, the chicks have to be collected for their safety and released for the weeks between mowing. After mowing the grass is very short, exposing the chicks to predation. After each cut of grass, the ground is injected or spread with slurry. However, despite the labour intensive help the fledging results are disappointing. Last year, in the region of Dwingeloo, of the 36 chicks radio tracked, only 1 fledged.
Henk-Jan Ottens measuring 2-week old chick.
The farm we visited still has a few extant young, the other nests in the surrounding area have failed, although there are some nests from second attempts that have not yet hatched. The oldest chicks are 30 days old, some 23 days and some 17 days. This year could be more promising than last, but as previous figures show, hatching success and fledging success are different things.
In the years before the teams put electric fences around the nests, they were marked with a stick to show the farmer where to avoid mowing, but losses were very high. The increase in hatched chicks has provided a psychological boost to the teams, which has been very important in keeping motivation. The psychology of working in Curlew conservation came up time and again, how to keep hope in the future when faced with constant decline. Seeing chicks is very important for people working in the field day in and day out, at least there is the potential for survival
The Drenthe project shows that despite fencing and tagging, the majority of chicks are still lost to mowing and predation. Increasing the mowing interval to 45 days helps, but it is still not enough to reach sustainable levels of one chick fledged per pair every other year. The volunteers try to find nests as close to the first egg being laid as possible and then encourage farmers to take the first cut just before the nest hatches. If this is successful, the following cut could be just after fledging but is dependent on the growth of grass and by-in from farmers.
Outside of mowing casualties the major predators are Fox, Stone Marten, Carrion Crow, Racoon Dog and Buzzard. 1000s of foxes are shot each year by hunters in Drenthe as part of farming practice to protect lambs, but shooting is also a cultural activity.
It was a highlight of the trip to join Henk-Jan and fieldworker Annemarie Loof in tracking tagged chicks to be measured and weighed. I had the privilege of releasing them with Annemarie. Please see an interview here describing her experience of being a fieldworker in Drenthe.
Annemarie Loof and Mary Colwell with 3-week old chicks.
DRENTHE AND ARABLE
Curlew nest in the middle of a maize crop.
Sugar beet, maize, potatoes, winter-wheat, zero-grazing sheds for cattle and windmills define the arable area of Drenthe. Some of the fields are over 1.5 kilometres long. Yet it is in the middle of this agri-industrial landscape that Curlews are most successful, more so than in the grasslands or nature reserves. Curlews don’t seek aesthetics, they need space, peace, protection and food. These huge fields provide more of a winning formula than other places. Predators find it hard to locate the nests (many of which are fenced), there is little disturbance from people or machinery, and drainage ditches provide good places to feed and hide. Henk-Jan thinks the productivity of the nests in arable areas maybe close to sustainable.
Fenced curlew nest near ditch in a large maise field.
This situation is somewhat similar to that in the Brecklands where Harry Ewing studied Curlews for his PhD at the University of East Anglia. Harry found that Curlews are more successful in hatching chicks if they nest in arable fields which have longer grass nearby. However, predation still limits fledging rates in the Brecks. See here for an excellent summary of Harry’s work from Wader Tales blog by Graham Appleton.
A mystery raised by Henk-Jan was the movement of Curlew down from their traditional habitat on heathland to intensive farmland around 30 years ago. What prompted a move away from their long-standing breeding grounds to seemingly inhospitable agricultural fields? He postulates it was increasing levels of predation in the heathlands, making farmland more attractive. This may be related to the arrival of the Red Fox in the area around that time, more on that later.
Windmills and arable crops.
Although this land isn’t heavily developed for housing, there are other pressures on ground-nesting birds that are not related to agriculture. There is high demand for sites for wind turbines resulting in extremely high prices for land; a farmer can be paid €75,000 per turbine, and it is hard to see how any agri-scheme can compete with that. See here for a paper on the effects on windfarms on Curlew and other waders.
OVERIJSSEL AND CURLEWS
Intensive silage field abuts nature reserve in Overijssel
In the province of Overijssel, Gerrit Gerritsen took us on a tour of his study area (400 square kilometres) where he has been monitoring Curlews since 1986 and ringing them since 2000. He also advises farmers and volunteers on agricultural policy and protection of nests and chicks. When Gerrit started his project there were around 440 pairs of nesting Curlew in the core of his area of 90 km2, today there are 100.
Annual adult Curlew survival is high, most return to breed, it is chick survival and fledging that is proving to be the limiting factor, as it is in Drenthe. Since 2013, a proportion of nests were protected using electric fences, which doubled hatching success, but Curlews are still not at sustainable levels. Gerrit tries to persuade farmers not to mow fields with a Curlew nest before June 15th, not only to protect eggs but also to give time for any chicks that have already hatched to grow to a sufficient size to run or fly.
In order to do this, farmers say they want to be given:
- Another field which they can mow early for cattle fodder.
- A higher payment from the government to compensate for late mowing so they can buy in the silage they have lost.
Working with famers
In particular areas, relations with farmers can be difficult due to the local, strong Calvinist ethic. Calvinism is a fundamental form of Protestantism which encourages efficient use of God-given resources and encourages hard work as a sign of godliness. Leaving land for nature is not traditionally part of Calvinist culture and negotiations on mowing regimes and leaving areas uncut for birds have proved difficult. As a result, in these particular communities, just 10% of the area is managed well for ground-nesting birds.
Pray and Work’ embossed into a traditional Calvinist farmhouse roof near Hasselt
Gerrit was spurred on to begin a ringing project as large numbers of waders were shot over France in the winter, and it was important to find out where the Overijssel Curlews were spending the non-breeding season. He has since discovered that around 50% go to the UK and the same number to France, with only a few to other places. Despite the moratorium on shooting Curlew, illegal hunting seems to continue in France. For example, three satellite-tagged birds were shot in the first weekend of the 2022 autumn hunting season. He has also discovered that as the climate is warming, an increasing number of birds are choosing to stay in the Netherlands rather than migrate.
Another consequence of ringing is the discovery that most fledged birds come back to breed within 5 km of where they were hatched. This has proved to be a morale-boosting finding for local volunteers who relate to and bond with their local birds.
Rabies and Foxes
The change in farming practices from late mowing and small-scale, mixed farms to today’s intensive model is certainly responsible in part, but in a marked difference to Drenthe, Gerrit thinks predation by foxes is major problem. From the 1970s onwards, an anti-rabies programme began across Europe, and Germany was officially rabies free by 2007. It is thought Foxes crossed from Germany into the Netherlands as the Fox population recovered and expanded westwards. There were few if any Foxes in the wet lowlands of the region before the eradication of rabies. Gerrit found his first predated Curlew (decapitated), still on a nest, which appears to have been killed by a Fox in 1995, and discussions with local hunters confirmed the increasing presence of Fox across the region. Could this explain the movement of Curlew from heathland to farmland at the same time? Other predators such as Buzzard, have also increased as persecution has declined, and the landscape became more suitable for them. It is too complex to discuss in detail here, but the basic message is there has been a recovery of predator species over the last few decades and a consequent decrease in ground-nesting birds.
Pictured below is an organic gouda. The dairy factory is in the heart of the Curlew area. It was launched in 2008 as part of the Nederland-Gruttoland (Godwit land) project and is now sold all over the country (see here). The farmers who produce the milk are recognised (by BirdLife standards) as being bird-friendly and receive a higher milk price on top of any agri-environment schemes, which can amount to tens of thousands of euros depending on the amount of milk used in the bird-friendly products and the percentage of land managed for birds on the farm. When setting up the scheme the farmers said they preferred this direct and quick form of payment from the dairy factory rather than through the bureaucracy-heavy AES schemes. In practice they receive both.
Gerrit Gerritsen with an organic gouda made from milk on a farm that manages land for Curlew
Overijssel is a traditional, religious part of the Netherlands, which is developing and intensifying whilst retaining its past culture. The key to success is to find ways to engage positively with this heritage to make birds like Curlew integral to the development of this intensively managed region.
With resources, organisation and people-power it is possible to substantially increase the hatching success of nests in both silage and arable settings. The premise is that more chicks will fledge simply because of the increased numbers. Is this level of intervention sustainable and affordable over a large area and over a long time frame? However, even with increased hatching success the fledging rate, particularly in silage fields, is substantially below that needed for a stable population. Agri payments can go some way to encouraging farmers to cut late to reduce mowing pressure, but predation is still a major issue. The new ELM scheme gives an opportunity for more investment in curlew but this needs to be designed to give farmers flexibility and to promote cooperation at a local landscape level.
Predator control is more socially acceptable in the Netherlands than in the UK, but even so predation is at unmanageable levels in many areas. Could predator management be affordable at the level of intensity and over the required time-frame required to make a meaningful difference? Would society accept it?
The only long-term solution is to re-frame the way we manage land. The agricultural and sporting sectors, as well as centres of human population, must work together to make conditions better for ground-nesting birds like Curlew. Tackling the high numbers of predators through reducing food availability and sites for denning/nesting, rather than through active control could be a shared vision, but will require education and outreach. For example, the USA has reduced problems with Black Bears by using bear-proof rubbish bins and being strict on littering. Until this societal level of change happens, we are left with expensive, targeted measures to keep the population of Curlew viable.
In 2021, Mary contributed to a paper in British Birds (Douglas, D.J.T. et al. (2021) Recovering the Eurasian Curlew in the UK and Ireland: progress since 2015 and looking ahead. British Birds, v.114, p.341-350.) It was an update on the 2015 paper that identified Curlew as the most pressing bird priority in the UK. The conclusion to that paper remains, and both our trips to the Netherlands and Finland support it….
“We are only at the beginning of Curlew recovery in the UK and Ireland. One thing that the Curlew does have on its side is the weight of public affection and a desire to secure its future. If we all work together, we might just have a chance of doing so.”
Mary, Mike and Rebecca would like to thank everyone for their generous hospitality and for taking time to show them around, provide information and arrange access to sites.