ELLENBROEK F BUYS J & OOSTERVELD E (1998) Nature-oriented management of set-aside land: new opportunities with rotational set-aside. LIMOSA 71 (3): 95-108.

In The Netherlands, much of the research on birds in agricultural habitats has been carried out on meadow birds in grassland areas. Until now, arable land has been given little attention. Like in grassland, the changes in farming practice on arable land must have had serious impact on breeding bird communities. Strongly negative population trends of some relatively well surveyed farmland birds like Grey Partridge and Corn Bunting confirm this expectation.
      After an absence of a few decades, set-aside land has returned in 1988 as part of the Dutch agricultural 1andscape. Since 1992, arable farmers wanting to qualify for income support from the European Union have to set-aside part of their land. Experiences in other European countries indicate that specific management regimes for set-aside fields may increase the natural value of arable farming areas. So far, little experience has been gained in The Netherlands, in particular with rotational set-aside. Therefore, the Centre for Agriculture and Environment initiated a field study on the effects of nature-oriented management of set-aside land on (breeding) birds, along with other fauna and flora.
      Between 1993 and 1995, the number of breeding birds was surveyed on 124 plots (141 ha) situated in various parts of the country. Territories of 25 species were recorded, the majority however occurred only in low numbers. Of eight species rather high numbers were recorded (Tab. 4). They reached densities of 0.8 - 2.8 territories per 10 ha. Skylark and Yellow Wagtail were most abundant. The density of seven species was at least twice as high as in the best reference areas of cropped land. Only Mallard did not show a higher density. The density of all species together was at least three times higher than in the reference areas. There were no significant differences concerning the vegetation type of the set-aside land and the time of soil preparation. Field margins yielded higher densities than entire fields. In the south-western province of Zeeland more species and higher numbers were recorded than in the northern and the south-eastern part of the country.
      The relatively high numbers of at least seven species of breeding birds indicate the suitability of set-aside land as breeding site and/or feeding area. This can be explained by the absence of serious disturbance after soil preparation. Moreover, the use of pesticides was very low. This resulted in the development of a relatively rich vegetation and a high density of insects and other invertebrates. Species like Skylark, Yellow Wagtail, Meadow Pipit and Grey Partridge took benefit from this food source.
      The effect of set-aside land, especially small fields, on birds is dependent on the surrounding landscape. To obtain good results, the management regime of set-aside land should meet the demands of local populations of farmland birds, taking the restraints of the surrounding landscape into account. When these local conditions are met, properly managed set-aside land can be beneficial to threatened birds in the Netherlands, like Grey Partridge, Barn Owl, Yellowhammer and Corn Bunting. Incentives to encourage nature-oriented management of setaside land are therefore desirable and useful.

[free pdf] [dutch summary]