Birds of arable land caught in a downward spiral
Older wildflower strips with a variety of structures such as shrubs, brambles and dry stems from the previous year offer cover and perches for many bird species. © Jérôme Duplain
In the past century, birds that breed on arable land have severely declined. The downward spiral continues despite federal programmes to protect biodiversity in agricultural areas, indicating that measures urgently need to be adjusted. Several successful projects point the way.
Arable fields account for one quarter of the total area of farmland and provide important habitats for breeding birds. Eight species are considered typical of this habitat in Switzerland: Grey Partridge, Common Quail, Northern Lapwing, Eurasian Skylark, Western Yellow Wagtail, Common Stonechat, Common Whitethroat and Corn Bunting. They all breed on arable land, building their nests among the crops or in adjacent areas of uncultivated land such as fallow land or neglected slopes. While several other species can also be observed on arable land, they generally nest in different habitats.
An alarming situation
In the second half of the 20th century, the populations of birds on arable land collapsed across Europe, and Switzerland was no exception. The characteristic species still present today are concentrated in the vast fields of the western Plateau, the Ajoie JU and the Klettgau SH, although certain species, Eurasian Skylark and Common Quail in particular, also occupy meadows and pastures in the Jura and the Alps.
Since 1993–1996, the situation has continued to worsen for these eight species, as the distribution change maps illustrate, especially in the central and eastern parts of the Plateau, in the Pre-Alps and in the plains of the large Alpine valleys. Several regional surveys confirm this trend; the Common Stonechat is the only positive exception to the general pattern.

Distribution change since 1993–1996 of typical birds of arable land. The map combines the distribution change maps of all eight species.
Positive trends, associated with local conservation projects for farmland birds and their habitats, are apparent in very few areas, some examples being the Champagne genevoise, Grosses Moos BE/FR and the Klettgau.

Distribution in 2013–2016 of typical birds of arable land. The map combines all records per kilometre square of the following eight species: Grey Partridge, Common Quail, Northern Lapwing, Eurasian Skylark, Western Yellow Wagtail, Common Stonechat, Common Whitethroat and Corn Bunting.
Arable land under pressure
All birds of arable land are heavily dependent on agriculture in the plains and its methods of cultivation. Exploitation is generally intensive, subject to processes of rationalisation and industrialisation and the widespread use of pesticides. More environmentally friendly forms of production such as organic farming or low-intensity cereal production (labelled «extenso» in Switzerland) are only applied on 20 % of lowland arable land, which has in turn lost 210 km2 of its area since 1997 (–5 %), largely to building development.
To compensate for the negative impact of intensive production on biodiversity, the federal government supports the designation of biodiversity promotion areas (BPA) and has published a list of target species in farmland. Among the five different types of BPA in arable land, wildflower strips, rotational fallows and field margins are particularly effective in the conservation of several target species and are considered high-quality habitats. Birds benefit enormously from wildflower strips, especially older strips that offer a rich variety of structures. At present, however, high-quality BPA only account for 0.8 % of arable land. That is an extremely small figure compared to 8 % of high-quality BPA in meadows and pastures. It goes without saying that high-quality BPA are much too rare in arable land to stop the decline of birds in this habitat.
Achievable objectives
Birds of arable land desperately need more suitable habitat. The successful projects near Geneva, in the Grosses Moos and in the Klettgau demonstrate that at least 3 % of area in arable land must be set aside for high-quality BPA, mainly in the form of wildflower strips and field margins. This would mean tripling the current area of BPA. At the landscape level, including the surrounding area that is not cultivated, at least 10–14 % of high-quality habitat is required to effectively promote threatened farmland species. The successful projects demonstrate that these objectives are both achievable and profitable for farmers. Such projects urgently need to receive federal support. At the same time, low-intensity farming practices need to be developed.
The fate of field birds and biodiversity in arable land is directly dependent on our agricultural policy decisions. We need to make sure these decisions are focussed on reconciling agricultural productivity with the protection of biodiversity.
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